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2022-06-30
0.0539
0.0316
2024-06-30
2024-09-30
0.1889
0.2670
-0.0214
0.2226
0.3832
0.1291
-0.2159
0.1606
0.1907
0.0274
2020-12-31
2020-03-31
0.3136
0.1313
-0.1396
0.2616
0.0280
0.2949
-0.1112
0.1086
0.0344
0.0291
2020-03-31
2020-12-31
0.0062
0.3031
-0.0823
0.3157
0.3150
0.1655
-0.2949
0.2267
0.0747
0.1482
2020-06-30
2022-06-30
0.0088
0.2965
-0.1270
0.3146
0.2645
0.0993
-0.2870
0.1277
-0.0076
0.2288
2020-06-30
2022-06-30
-0.0288
0.2911
-0.1800
0.3024
0.3164
0.0868
-0.2851
0.1512
0.0211
0.1774
2020-06-30
2020-03-31
-0.0240
0.2953
-0.1750
0.3075
0.3247
0.0939
-0.2828
0.0241
0.1805
0.1520
2020-06-30
2020-03-31
-0.0460
0.3217
-0.2448
0.3381
0.2868
0.1087
-0.3514
0.1442
0.0055
0.1498
2020-03-31
2020-06-30
0.0142
0.4168
-0.1773
0.2798
0.2723
-0.0769
-0.2611
0.0569
0.2605
0.0585
2020-03-31
2020-06-30
0.0149
0.4853
-0.2161
0.2789
0.4043
0.0297
-0.3333
0.0999
0.1040
0.2484
2020-06-30
2020-03-31
0.2475
0.1349
0.2818
2023-12-31
2023-09-30
0.0809
0.1368
0.4009
0.2034
0.3226
0.1523
-0.2812
-0.0533
-0.2357
0.2193
2020-03-31
2020-06-30
-0.3243
-0.2428
0.1034
0.2425
2024-09-30
2022-09-30
-0.1693
0.1341
0.0906
0.1609
2022-06-30
2023-12-31
N-1A
WILLIAM BLAIR FUNDS
2026-05-01
WILLIAM BLAIR GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0075
0.0075
0.0075
0.0025
0
0
0.0025
0.0016
0.0012
0.0125
0.0091
0.0087
0.0005
0.0120
0.0091
0.0087
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
122
392
682
1507
93
290
504
1120
89
278
482
1073
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 62% of the average value of its portfolio.
0.62
PRINCIPAL INVESTMENT STRATEGIES:
The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), of U.S. growth companies of all sizes that are expected to exhibit quality growth characteristics. The Fund invests primarily in equity securities issued by companies that typically have market capitalizations no smaller than the smallest capitalized company, and no larger than the largest capitalized company, included in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and growth prospects similar to companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index, but that may have market capitalizations outside the range of companies included in the index. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index is a widely recognized, unmanaged index that measures the performance of the 3,000 largest U.S. companies. The size of companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of the companies in the index. As of March 31, 2026, the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $4 million and $4.2 trillion. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Growth Index, the Fund’s performance benchmark, measures the performance of Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> companies with higher price‑to‑book ratios and higher forecasted growth values.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser evaluates the extent to which a company meets the quality growth criteria set forth below. All of the criteria are evaluated relative to the valuation of the security. The weight given to a particular investment criterion will depend upon the circumstances, and Fund holdings may not meet all of the following criteria: (a) the company should be, or should have the expectation of becoming, a significant provider in the primary markets it serves, (b) the company should have some distinctive attribute relative to present or potential competitors (for example, this may take the form of proprietary products or processes, a unique distribution system, an entrenched brand name or an especially strong financial position relative to its competition), (c) the company should participate in an industry expected to grow rapidly due to economic factors or technological change or should grow through market share gains in its industry and (d) the company should have a strong management team.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The S&P 500<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Growth Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The S&P 500® Index represents a broad measure of market performance, while the Russell 3000® Growth Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn25.68% (<span><span><span><span><span class="sec-hidden" style="-sec-ix-hidden:t_44_79393aab_e7a4_a8cb_1d31_29eae1b699df">2Q20</span></span></span></span></span>)Lowest QuarterlyReturn(21.42)% (<span class="sec-hidden" style="-sec-ix-hidden:t_44_16976a95_a5d1_1c88_1a14_95307509f84e">2Q22</span>)
Highest QuarterlyReturn
0.2568
Lowest QuarterlyReturn
-0.2142
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1019
0.0969
0.1394
0.0211
0.0515
0.0925
0.1166
0.0718
0.1028
0.1057
0.1002
0.1427
0.1788
0.1442
0.1482
0.1815
0.1459
0.1759
2019-05-02
2019-05-02
2019-05-02
0.1066
0.1008
0.1434
0.1788
0.1442
0.1543
0.1815
0.1459
0.1839
WILLIAM BLAIR LARGE CAP GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Large Cap Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0060
0.0060
0.0060
0.0025
0
0
0.0017
0.0015
0.0004
0.0102
0.0075
0.0064
0.0012
0.0010
0.0004
0.0090
0.0065
0.0060
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
92
313
552
1237
66
230
407
921
61
201
353
795
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result inhigher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 41% of the average value of its portfolio.
0.41
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in stocks of large capitalized (“large cap”) companies. The Fund invests primarily in a portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), of large cap U.S. growth companies that are expected to exhibit quality growth characteristics. For purposes of the Fund, the Adviser considers a company to be a large cap company if it has a market capitalization no smaller than the smallest capitalized company included in the Russell 1000® Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and growth prospects similar to large cap companies, but that may have market capitalizations below the market capitalization of the smallest member of the Russell 1000® Index.<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index is a widely recognized, unmanaged index that measures the performance of the 1,000 largest U.S. companies. The companies in the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index are considered representative of large cap companies. The size of companies in the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of the companies included in the index. As of March 31, 2026, the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $907 million and $4.2 trillion. The Russell 1000<span style="font-weight: bold;"><span style="font-style: italic;"><sup style="font-size: 75%; vertical-align: top;">®</sup></span></span> Growth Index, the Fund’s performance benchmark, measures the performance of those Russell 1000 companies with a greater-than-average growth orientation.</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser evaluates the extent to which a company meets the quality growth criteria set forth below. All of the criteria are evaluated relative to the valuation of the security. The weight given to a particular investment criterion will depend upon the circumstances, and Fund holdings may not meet all of the following criteria: (a) the company should be, or should have the expectation of becoming, a significant provider in the primary markets it serves, (b) the company should have some distinctive attribute relative to present or potential competitors (for example, this may take the form of proprietary products or processes, a unique distribution system, an entrenched brand name or an especially strong financial position relative to its competition), (c) the company should participate in an industry expected to grow rapidly due to economic factors or technological change or should grow through market share gains in its industry and (d) the company should have a strong management team.</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">THE FUND IS NON‑DIVERSIFIED UNDER THE INVESTMENT COMPANY ACT OF 1940, AS AMENDED, AND MAY INVEST A LARGER PERCENTAGE OF ITS ASSETS IN FEWER ISSUERS THAN DIVERSIFIED MUTUAL FUNDS.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Non‑Diversification Risk.</span> The Fund is non‑diversified, meaning that it is permitted to invest a larger percentage of its assets in fewer issuers than diversified mutual funds. Thus, the Fund may be more susceptible to adverse developments affecting any single issuer held in its portfolio and may be more susceptible to greater losses because of these developments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span><span style="font-weight: bold;"> </span>To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 1000® Index represents a broad measure of market performance, while the Russell 1000® Growth Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1-800-635-2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 1000® Index represents a broad measure of market performance, while the Russell 1000® Growth Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1-800-635-2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn25.58% (<span class="sec-hidden" style="-sec-ix-hidden:t_47_c679a5f0_dc56_d484_85a0_6c558dcad338">2Q20</span>)Lowest QuarterlyReturn(22.25)% (<span class="sec-hidden" style="-sec-ix-hidden:t_47_da7abc63_376e_9e8b_a56e_7439c28859e2">2Q22</span>)
Highest QuarterlyReturn
0.2558
Lowest QuarterlyReturn
-0.2225
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1136
0.1111
0.1596
0.0906
0.1005
0.1468
0.0832
0.0875
0.1317
0.1168
0.1140
0.1626
0.1737
0.1359
0.1459
0.1856
0.1532
0.1813
2019-05-02
2019-05-02
2019-05-02
0.1171
0.1145
0.1595
0.1737
0.1359
0.1508
0.1856
0.1532
0.1905
WILLIAM BLAIR MID CAP VALUE FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Mid Cap Value Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0070
0.0070
0
0
0.0855
0.0852
0.0925
0.0922
0.0850
0.0852
0.0075
0.0070
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
77
1924
3618
7261
72
1914
3605
7246
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 28% of the average value of its portfolio.
0.28
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of medium-capitalized (“mid cap”) companies. For purposes of the Fund, the Adviser considers a company to be a mid cap company if it has a market capitalization no smaller than the smallest capitalized company, and no larger than the largest capitalized company, included in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and value prospects similar to mid cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The Fund may invest in equity securities listed on a national securities exchange or traded in the over‑the‑counter markets. The Fund invests primarily in common stocks, but it may also invest in other types of equity securities, including real estate investment trusts (“REITs”) and American Depositary Receipts (“ADRs”). <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index measures the performance of the mid cap segment of the U.S. equity universe. The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index is a subset of the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. It includes approximately 800 of the smallest securities based on a combination of their market cap and current index membership. The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents approximately 22% of the total market capitalization of the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> companies as of March 31, 2026. The companies in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index are considered representative of mid cap companies. The size of companies in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of the companies included in the index. As of March 31, 2026, the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $907 million and $116.8 billion. The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Value Index, the Fund’s performance benchmark, measures the performance of those Russell Midcap companies with lower price‑to‑book ratios and lower forecasted growth values.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In selecting investments for the Fund, the Adviser typically looks to invest in companies with leading market share positions, shareholder oriented managements, and strong balance sheet and cash flow ratios. Usually, the shares of the companies the Adviser buys are selling at a price to earnings ratio below the average price to earnings ratio of the stocks that comprise the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. In addition, the companies selected by the Adviser usually have higher returns on equity and capital than the average company in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The Adviser screens the Fund’s universe of potential investments to identify potentially undervalued securities based on factors such as financial strength, earnings valuation, and earnings quality. The Adviser further narrows the list of potential investments through traditional fundamental security analysis, which may include interviews with company management and a review of the assessments and opinions of outside analysts and consultants. Securities are sold when the Adviser believes the shares have become relatively overvalued or it finds more attractive alternatives. The Adviser generally will not sell a security merely due to market appreciation outside the Fund’s target capitalization range if it believes the company has valuation upside potential.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Mid Cap Company Risk.</span> Stocks of mid cap companies involve greater risk than those of larger, more established companies. This is because mid cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Mid cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of mid cap companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">REIT Risk.</span> REITs are pooled investment vehicles that own, and usually operate, income-producing real estate. REITs are susceptible to the risks associated with direct ownership of real estate, such as the following: declines in property values; increases in property taxes, operating expenses, interest rates or competition; overbuilding; zoning changes; and losses from casualty or condemnation. REITs typically incur fees that are separate from those of the Fund. Accordingly, the Fund’s shareholders will indirectly bear a proportionate share of the REITs’ operating expenses, in addition to paying Fund expenses. REIT operating expenses are not reflected in the fee table and example in this Prospectus.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The Fund’s investments in ADRs are subject to foreign securities risk. ADRs are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and traded on U.S. exchanges. Although ADRs are alternatives to directly purchasing the underlying foreign securities in their national markets and currencies, they continue to be subject to many of the risks associated with investing directly in foreign securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the value investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span><span style="font-weight: bold;"> </span>Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Value Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell Midcap® Value Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the calendar years since the Fund commenced operations.
Highest QuarterlyReturn
Highest QuarterlyReturn10.92% (<span class="sec-hidden" style="-sec-ix-hidden: t_41_3de8376c_15e9_5379_c28a_28a023604cb6;">4Q23</span>)Lowest QuarterlyReturn(6.04)% (<span class="sec-hidden" style="-sec-ix-hidden: t_41_2a5c878a_b284_e8ec_d104_cd11aae5a062;">2Q24</span>)
0.1092
Lowest QuarterlyReturn
-0.0604
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class I shares and on a before-tax basis for Class R6 shares. After-tax returns for Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class I shares and on a before-tax basis for Class R6 shares. After-tax returns for Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
2022-03-16
2022-03-16
2022-03-16
2022-03-16
2022-03-16
2022-03-16
0.0733
0.0603
0.0697
0.0569
0.0460
0.0465
0.0739
0.0608
0.1715
0.1426
0.1105
0.0779
WILLIAM BLAIR SMALL‑MID CAP CORE FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Small‑Mid Cap Core Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0090
0.0090
0
0
0.0029
0.0014
0.0119
0.0104
0.0024
0.0014
0.0095
0.0090
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
97
354
631
1422
92
317
560
1258
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 81% of the average value of its portfolio.
0.81
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of small capitalized (“small cap”) and medium capitalized (“mid cap”) companies. The Fund invests in a diversified portfolio of equity securities, primarily common stocks, of small cap and mid cap U.S. companies that the Adviser deems to be of high quality but undervalued by the marketplace. For purposes of the Fund, the Adviser considers a company to be a small cap or a mid cap company if it has a market capitalization no larger than the largest capitalized company included in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics similar to small cap and mid cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index measures the performance of the 800 companies with the lowest market capitalizations in the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The size of companies in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of companies included in the index. As of March 31, 2026, the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $907 million and $116.8 billion. The Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Index, the Fund’s performance benchmark, measures the performance of the 2,500 smallest companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index with a weighted average market capitalization of approximately $11.6 billion, median capitalization of $1.5 billion and market capitalization of the largest company at $97.5 billion as of March 31, 2026.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser evaluates the extent to which a company meets the criteria set forth below. All of the criteria are evaluated relative to the valuation of the security. The weight given to a particular investment criterion will depend upon the circumstances, and Fund holdings may not meet all of the following criteria: (a) the company should be, or should have the expectation of becoming, a significant provider in the primary markets it serves; (b) the company should have some distinctive attribute relative to present or potential competitors (this may, for example, take the form of proprietary products or processes, a unique distribution system, an entrenched brand name or an especially strong financial position relative to its competition); and (c) the company should have a strong management team.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Mid Cap Company Risk.</span> Stocks of small and mid cap companies involve greater risk than those of larger, more established companies. This is because small and mid cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and mid cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and mid cap companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell 2500TM Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the calendar years since the Fund commenced operations.
Highest QuarterlyReturn
Highest QuarterlyReturn28.67% (<span class="sec-hidden" style="-sec-ix-hidden: t_47_a81ef922_5e05_ea20_c87d_79fa00557cfe;">4Q20</span>)Lowest QuarterlyReturn(26.97)% (<span class="sec-hidden" style="-sec-ix-hidden: t_47_e720c1a9_2679_aaff_4f55_133fe122d861;">1Q20</span>)
0.2867
Lowest QuarterlyReturn
-0.2697
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
2019-10-01
2019-10-01
2019-10-01
2019-10-01
2019-10-01
2019-10-01
0.0127
0.0617
0.0925
0.0057
0.0595
0.0906
0.0125
0.0483
0.0740
0.0133
0.0623
0.0930
0.1715
0.1315
0.1537
0.1191
0.0726
0.1033
WILLIAM BLAIR SMALL‑MID CAP GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Small‑Mid Cap Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0.0094
0.0025
0
0
0.0018
0.0018
0.0005
0.0137
0.0112
0.0099
0.0013
0.0013
0.0005
0.0124
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
126
421
738
1635
101
343
604
1352
96
310
542
1208
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 57% of the average value of its portfolio.</div>
0.57
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in stocks of small capitalized (“small cap”) and medium capitalized (“mid cap”) companies. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), of small cap and mid cap U.S. growth companies that are expected to exhibit quality growth characteristics. For purposes of the Fund, the Adviser considers a company to be a small cap or mid cap company if it has a market capitalization no larger than the largest capitalized company included in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and growth prospects similar to small cap and mid cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index.<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index measures the performance of the 800 companies with the lowest market capitalizations in the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The size of companies in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of companies included in the index. As of March 31, 2026, the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $907 million and $116.8 billion. The Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Growth Index, the Fund’s performance benchmark, measures the performance of those Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> companies with higher price‑to‑book ratios and higher forecasted growth values. The Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Index measures the performance of the 2,500 smallest companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index with a weighted average market capitalization of approximately $11.6 billion, median capitalization of $1.5 billion and market capitalization of the largest company at $97.5 billion as of March 31, 2026.</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser evaluates the extent to which a company meets the quality growth criteria set forth below. All of the criteria are evaluated relative to the valuation of the security. The weight given to a particular investment criterion will depend upon the circumstances, and Fund holdings may not meet all of the following criteria: (a) the company should be, or should have the expectation of becoming, a significant provider in the primary markets it serves, (b) the company should have some distinctive attribute relative to present or potential competitors (for example, this may take the form of proprietary products or processes, a unique distribution system, an entrenched brand name or an especially strong financial position relative to its competition), (c) the company should participate in an industry expected to grow rapidly due to economic factors or technological change or should grow through market share gains in its industry and (d) the company should have a strong management team.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Mid Cap Company Risk.</span> Stocks of small and mid cap companies involve greater risk than those of larger, more established companies. This is because small and mid cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and mid cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and mid cap companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Growth Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell 2500TM Growth Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn26.45% (<span class="sec-hidden" style="-sec-ix-hidden:t_44_6205084e_e222_835a_5cd5_2ea55e248506">2Q20</span>)Lowest QuarterlyReturn(21.07)% (<span class="sec-hidden" style="-sec-ix-hidden:t_44_72e7066f_0cb7_5b5a_85ec_a35065cd050b">2Q22</span>)
0.2645
Lowest QuarterlyReturn
-0.2107
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.0037
0.0180
0.0967
-0.0052
-0.0009
0.0799
0.0057
0.0116
0.0763
0.0062
0.0206
0.0995
0.1715
0.1315
0.1429
0.1031
0.0298
0.1055
2019-05-02
2019-05-02
2019-05-02
0.0069
0.0211
0.0720
0.1715
0.1315
0.1469
0.1031
0.0298
0.0897
WILLIAM BLAIR SMALL‑MID CAP VALUE FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Small‑Mid Cap Value Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0080
0.0080
0
0
0.0424
0.0419
0.0504
0.0499
0.0419
0.0419
0.0085
0.0080
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first two years. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
87
1136
2185
4803
82
1122
2162
4763
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result inhigher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 40% of the average value of its portfolio.
0.40
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of small capitalized (“small cap”) and medium capitalized (“mid cap”) companies. For purposes of the Fund, the Adviser considers a company to be a small cap or mid cap company if it has a market capitalization no larger than the largest capitalized company included in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and value prospects similar to small to mid cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The Fund may invest in equity securities listed on a national securities exchange or traded in the over‑the‑counter markets. The Fund invests primarily in common stocks, but it may also invest in other types of equity securities, including real estate investment trusts (“REITs”) and American Depositary Receipts (“ADRs”). <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index measures the performance of the 800 companies with the lowest market capitalizations in the Russell 1000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The size of companies in the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of companies included in the index. As of March 31, 2026, the Russell Midcap<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $907 million and $116.8 billion. The Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Value Index, the Fund’s performance benchmark, measures the performance of those Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM </sup>companies with lower price‑to‑book ratios and lower forecasted growth values.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In selecting investments for the Fund, the Adviser typically looks to invest in companies with leading market share positions, shareholder-oriented managements, and strong balance sheet and cash flow ratios. Usually, the shares of the companies the Adviser buys are selling at a price to earnings ratio below the average price to earnings ratio of the stocks that comprise the Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Value Index. In addition, the companies selected by the Adviser usually have higher returns on equity and capital than the average company in the Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Value Index. The Adviser screens the Fund’s universe of potential investments to identify potentially undervalued securities based on factors such as financial strength, earnings valuation and earnings quality. The Adviser further narrows the list of potential investments through traditional fundamental security analysis, which may include interviews with company management and a review of the assessments and opinions of outside analysts and consultants. Securities are sold when the Adviser believes the shares have become relatively overvalued or it finds more attractive alternatives. The Adviser generally will not sell a security merely due to market appreciation outside the Fund’s target capitalization range if it believes the company has valuation upside potential.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market</span><span style="font-weight: bold;"> </span><span style="font-weight: bold;">Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Mid Cap Company Risk.</span> Stocks of small and mid cap companies involve greater risk than those of larger, more established companies. This is because small and mid cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and mid cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and mid cap companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">REIT Risk.</span> REITs are pooled investment vehicles that own, and usually operate, income-producing real estate. REITs are susceptible to the risks associated with direct ownership of real estate, such as the following: declines in property values; increases in property taxes, operating expenses, interest rates or competition; overbuilding; zoning changes; and losses from casualty or condemnation. REITs typically incur fees that are separate from those of the Fund. Accordingly, the Fund’s shareholders will indirectly bear a proportionate share of the REITs’ operating expenses, in addition to paying Fund expenses. REIT operating expenses are not reflected in the fee table and example in this Prospectus.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The Fund’s investments in ADRs are subject to foreign securities risk. ADRs are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and traded on U.S. exchanges. Although ADRs are alternatives to directly purchasing the underlying foreign securities in their national markets and currencies, they continue to be subject to many of the risks associated with investing directly in foreign securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 2500<sup style="font-size: 75%; vertical-align: top;">TM</sup> Value Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell 2500TM Value Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of performance of the Fund’s Class I shares over the past calendar year.
Highest Quarterly<br/>Return7.89% (<span class="sec-hidden" style="-sec-ix-hidden: t_60_7cc57f91_dd56_65c0_bdc3_11166066785f;">3Q24</span>)Lowest Quarterly<br/>Return(6.07)% (<span class="sec-hidden" style="-sec-ix-hidden: t_60_38879bbd_c7a4_cdae_c5c4_8bbfd6b8a730;">2Q24</span>)
Highest QuarterlyReturn
0.0789
Lowest QuarterlyReturn
-0.0607
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
2023-08-17
2023-08-17
2023-08-17
2023-08-17
2023-08-17
2023-08-17
0.0316
0.0635
0.0280
0.0591
0.0213
0.0484
0.0321
0.0638
0.1715
0.2185
0.1273
0.1466
WILLIAM BLAIR SMALL CAP GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Small Cap Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0.0094
0.0025
0
0
0.0020
0.0018
0.0007
0.0139
0.0112
0.0101
0.0015
0.0013
0.0007
0.0124
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
126
425
746
1656
101
343
604
1352
96
315
551
1230
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 94% of the average value of its portfolio.
0.94
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in stocks of small capitalized (“small cap”) companies. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), of small cap U.S. growth companies that are expected to exhibit quality growth characteristics. The Fund’s investments in small cap companies may include a significant weighting to micro‑cap companies (which, for purposes of the Fund, are companies with market capitalizations of $1 billion or less at the time of the Fund’s investment). For purposes of the Fund, the Adviser considers a company to be a small cap company if it has a market capitalization no larger than the largest capitalized company included in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and growth prospects similar to small cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index is a widely recognized, unmanaged index of common stocks that measures the performance of the 2,000 smallest companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The companies in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index are considered representative of small cap companies. The size of companies in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of the companies included in the index. As of March 31, 2026, the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $4 million and $38.3 billion. The Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Growth Index, the Fund’s performance benchmark, measures the performance of those Russell 2000 companies with a greater-than-average growth orientation.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser evaluates the extent to which a company meets the quality growth criteria set forth below. All of the criteria are evaluated relative to the valuation of the security. The weight given to a particular investment criterion will depend upon the circumstances, and Fund holdings may not meet all of the following criteria: (a) the company should be, or should have the expectation of becoming, a significant provider in the primary markets it serves, (b) the company should have some distinctive attribute relative to present or potential competitors (for example, this may take the form of proprietary products or processes, a unique distribution system, an entrenched brand name or an especially strong financial position relative to its competition), (c) the company should participate in an industry expected to grow rapidly due to economic factors or technological change or should grow through market share gains in its industry and (d) the company should have a strong management team.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Micro‑Cap Company Risk.</span> Stocks of small and micro cap companies involve greater risk than those of larger, more established companies. This is because small and micro cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and micro cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and micro cap companies may be more volatile and less liquid than securities of large capitalized companies. For purposes of the Fund, micro cap companies are companies with market capitalizations of $1 billion or less at the time of the Fund’s investment.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Growth Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell 2000® Growth Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn29.72% (<span class="sec-hidden" style="-sec-ix-hidden: t_348_6f8ecf06_cd1a_3d34_23f3_e65eac6091b2;">4Q20</span>)Lowest Quarterly<br/>Return(25.08)% (<span class="sec-hidden" style="-sec-ix-hidden: t_348_ea40639b_5975_a612_9821_68f1e217c0d3;">1Q20</span>)
0.2972
Lowest QuarterlyReturn
-0.2508
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.0274
0.0468
0.1210
0.0026
0.0217
0.0944
0.0272
0.0314
0.0926
0.0301
0.0495
0.1238
0.1715
0.1315
0.1429
0.1301
0.0318
0.0957
2019-05-02
2019-05-02
2019-05-02
0.0305
0.0501
0.0940
0.1715
0.1315
0.1469
0.1301
0.0318
0.0823
WILLIAM BLAIR SMALL CAP VALUE FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Small Cap Value Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0075
0.0075
0.0075
0.0025
0
0
0.0016
0.0018
0.0005
0.0116
0.0093
0.0080
0.0001
0.0004
0.0115
0.0089
0.0080
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
117
367
637
1408
91
292
511
1139
82
255
444
990
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 37% of the average value of its portfolio.
0.37
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of small capitalized (“small cap”) companies. For purposes of the Fund, the Adviser considers a company to be a small cap company if it has a market capitalization no larger than the largest capitalized company included in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index at the time of the Fund’s investment. Securities of companies whose market capitalizations no longer meet this definition after purchase may continue to be held in the Fund. To a limited extent, the Fund may also purchase stocks of companies with business characteristics and value prospects similar to small cap companies, but that may have market capitalizations above the market capitalization of the largest member of the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The Fund may invest in equity securities listed on a national securities exchange or traded in the over‑the‑counter markets. The Fund invests primarily in common stocks, but it may also invest in other types of equity securities, including real estate investment trusts (“REITs”) and American Depositary Receipts (“ADRs”). <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index is a widely recognized, unmanaged index of common stocks that measures the performance of the 2,000 smallest companies in the Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The companies in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index are considered representative of small cap companies. The size of companies in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index may change with market conditions. In addition, changes to the composition of the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index can change the market capitalization range of the companies included in the index. As of March 31, 2026, the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index included securities issued by companies that ranged in size between $4 million and $38.3 billion. The Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Value Index, the Fund’s performance benchmark, measures the performance of those Russell 2000 companies with lower price‑to‑book ratios and lower forecasted growth values.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In selecting investments for the Fund, the Adviser typically looks to invest in companies with leading market share positions, shareholder oriented managements, and strong balance sheet and cash flow ratios. Usually, the shares of the companies the Adviser buys are selling at a price to earnings ratio below the average price to earnings ratio of the stocks that comprise the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. In addition, the companies selected by the Adviser usually have higher returns on equity and capital than the average company in the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index. The Adviser screens the Fund’s universe of potential investments to identify potentially undervalued securities based on factors such as financial strength, earnings valuation, and earnings quality. The Adviser further narrows the list of potential investments through traditional fundamental security analysis, which may include interviews with company management and a review of the assessments and opinions of outside analysts and consultants. Securities are sold when the Adviser believes the shares have become relatively overvalued or it finds more attractive alternatives. The Adviser generally will not sell a security merely due to market appreciation outside the Fund’s target capitalization range if it believes the company has valuation upside potential.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span><span style="font-weight: bold;"> </span>The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Micro Cap Company Risk.</span> Stocks of small and micro cap companies involve greater risk than those of larger, more established companies. This is because small and micro cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and micro cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and micro cap companies may be more volatile and less liquid than securities of large capitalized companies. For purposes of the Fund, micro cap companies are companies with market capitalizations of $500 million or less at the time of the Fund’s investment.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">REIT Risk.</span> REITs are pooled investment vehicles that own, and usually operate, income-producing real estate. REITs are susceptible to the risks associated with direct ownership of real estate, such as the following: declines in property values; increases in property taxes, operating expenses, interest rates or competition; overbuilding; zoning changes; and losses from casualty or condemnation. REITs typically incur fees that are separate from those of the Fund. Accordingly, the Fund’s shareholders will indirectly bear a proportionate share of the REITs’ operating expenses, in addition to paying Fund expenses. REIT operating expenses are not reflected in the fee table and example in this Prospectus.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The Fund’s investments in ADRs are subject to foreign securities risk. ADRs are certificates evidencing ownership of shares of a foreign issuer that are issued by depositary banks and traded on U.S. exchanges. Although ADRs are alternatives to directly purchasing the underlying foreign securities in their national markets and currencies, they continue to be subject to many of the risks associated with investing directly in foreign securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the value investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">additional index. The Russell 3000<sup style="font-size: 75%; vertical-align: top;">®</sup> Index represents a broad measure of market performance, while the Russell 2000<sup style="font-size: 75%; vertical-align: top;">®</sup> Value Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. On July 16, 2021, the Fund acquired the assets and assumed the liabilities of the ICM Small Company Portfolio (the “Predecessor Fund”), a series of The Advisors’ Inner Circle Fund, in a reorganization (the “Reorganization”). In the Reorganization, former shareholders of the Predecessor Fund received Class I shares of the Fund. The Predecessor Fund was advised by Investment Counselors of Maryland, LLC, which was acquired by the Adviser. The Predecessor Fund’s (Institutional Class shares) performance and financial history have been adopted by Class I shares of the Fund following the Reorganization and are being used going forward from the date of the Reorganization. The performance of Class I shares of the Fund therefore reflects the performance of the Predecessor Fund prior to the Reorganization. The performance of the Predecessor Fund has not been restated to reflect the annual operating expenses of Class I shares of the Fund, which were different than those of the Predecessor Fund. Because the Fund had different fees and expenses than the Predecessor Fund, the Predecessor Fund would therefore have had different performance results if it was subject to the Fund’s fees and expenses. The Fund’s past performance (including the performance of the Predecessor Fund), before and after taxes, is not necessarily an indication of how the Fund will perform in the future and does not guarantee future results. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.</div>
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and anadditional index. The Russell 3000® Index represents a broad measure of market performance, while the Russell 2000® Value Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and anadditional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn29.75% (<span><span><span><span><span><span><span><span><span><span><span><span class="sec-hidden" style="-sec-ix-hidden: t_428_74dba039_75db_84d8_c1e5_a67435134e51;">4Q20</span></span></span></span></span></span></span></span></span></span></span></span>)Lowest Quarterly<br/>Return(35.02)% (<span class="sec-hidden" style="-sec-ix-hidden: t_428_525dbc7e_42a7_4e7e_36a6_09638610d9ef;">1Q20</span>)
Highest QuarterlyReturn
0.2975
Lowest QuarterlyReturn
-0.3502
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class N and Class R6 shares. After‑tax returns for Class N and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class N and Class R6 shares. After‑tax returns for Class N and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.0291
0.0631
0.0846
0.0237
0.0467
0.0678
0.0212
0.0467
0.0648
0.1715
0.1315
0.1429
0.1259
0.0888
0.0927
2021-07-19
2021-07-19
2021-07-19
2021-07-19
0.0261
0.0273
0.0301
0.0309
0.1715
0.1134
0.1259
0.0572
WILLIAM BLAIR GLOBAL LEADERS FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Global Leaders Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0085
0.0085
0.0085
0.0025
0
0
0.0088
0.0087
0.0078
0.0198
0.0172
0.0163
0.0083
0.0082
0.0078
0.0115
0.0090
0.0085
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
117
541
991
2239
92
462
856
1962
87
438
813
1867
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 81% of the average value of its portfolio.
0.81
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its total assets in a portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by companies of all sizes worldwide that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development, ranging from large, well-established companies to smaller companies at earlier stages of development, that are leaders in their country, industry or globally in terms of products, services or execution. The use of the term “global” in the Fund’s name is meant to emphasize that the Adviser looks for investment opportunities on a worldwide basis and the investment strategy is not constrained by the countries or regions in which companies are located. The Fund’s investments are normally allocated among at least five different countries. The Fund may invest in emerging markets, which include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">THE FUND IS NON‑DIVERSIFIED UNDER THE INVESTMENT COMPANY ACT OF 1940, AS AMENDED, AND MAY INVEST A LARGER PERCENTAGE OF ITS ASSETS IN FEWER ISSUERS THAN DIVERSIFIED MUTUAL FUNDS.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large-capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Non‑Diversification Risk.</span> The Fund is non‑diversified, meaning that it is permitted to invest a larger percentage of its assets in fewer issuers than diversified mutual funds. Thus, the Fund may be more susceptible to adverse developments affecting any single issuer held in its portfolio and may be more susceptible to greater losses because of these developments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. On January 27, 2026, the Fund’s benchmark changed from the MSCI All Country World Investable Market Index (net) to the MSCI All Country World Index (net). The primary reason for this change is to compare the Fund to a benchmark that more closely reflects the market and portfolio composition focus the Fund uses in its investment strategy. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
On January 27, 2026, the Fund’s benchmark changed from the MSCI All Country World Investable Market Index (net) to the MSCI All Country World Index (net). The primary reason for this change is to compare the Fund to a benchmark that more closely reflects the market and portfolio composition focus the Fund uses in its investment strategy.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn24.59% (<span class="sec-hidden" style="-sec-ix-hidden: t_479_d5815365_db6c_3071_8f62_7fead8bf162d;">2Q20</span>)Lowest Quarterly<br/>Return(19.72)% (<span class="sec-hidden" style="-sec-ix-hidden: t_479_c4498708_6f2a_7c26_0125_547386f63151;">2Q22</span>)
0.2459
Lowest QuarterlyReturn
-0.1972
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1482
0.0446
0.0998
0.0189
-0.0045
0.0656
0.1769
0.0316
0.0780
0.1520
0.0474
0.1028
0.1523
0.0479
0.1034
0.2234
0.1119
0.1172
0.2206
0.1075
0.1145
WILLIAM BLAIR INTERNATIONAL LEADERS FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair International Leaders Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0085
0.0085
0.0085
0.0025
0
0
0.0017
0.0018
0.0006
0.0127
0.0103
0.0091
0.0012
0.0013
0.0006
0.0115
0.0090
0.0085
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
117
391
685
1523
92
315
556
1248
87
284
498
1114
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 91% of the average value of its portfolio.
0.91
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by companies of all sizes domiciled outside the U.S. that the Adviser believes have above-average growth, profitability and quality characteristics. Under normal market conditions, the Fund typically holds a limited number of securities (<span style="font-style: italic;">i.e.</span>, 40‑70 securities). The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development, that are leaders in their country, industry or globally in terms of products, services or execution. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time. Normally, the Fund’s investments will be divided among Continental Europe, the United Kingdom, Canada, Japan and the markets of the Pacific Basin. The Fund may invest the greater of 40% of its net assets or twice the emerging markets component of the MSCI All Country World ex USA Investable Market Index (“ACWI ex USA IMI”) (net) in emerging markets, which include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance. In addition, because the Fund may focus its investments in a limited number of securities, its performance may be more volatile than a fund that invests in a greater number of securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn21.43% (<span class="sec-hidden" style="-sec-ix-hidden:h_485_e50a4669_1495_490d_95e2_3c4ab948b529">2Q20</span>)Lowest QuarterlyReturn(19.24)% (<span><span class="sec-hidden" style="-sec-ix-hidden:t_518_38b46687_3ffe_91b7_b1c3_667898ff5821">2Q22</span></span>)
0.2143
Lowest QuarterlyReturn
-0.1924
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.2288
0.0151
0.0742
0.2072
0.0099
0.0696
0.1500
0.0115
0.0596
0.2317
0.0176
0.0769
0.2327
0.0181
0.0776
0.3196
0.0777
0.0837
WILLIAM BLAIR INTERNATIONAL GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair International Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0085
0.0085
0.0085
0.0025
0
0
0.0021
0.0018
0.0007
0.0131
0.0103
0.0092
0.0016
0.0013
0.0007
0.0115
0.0090
0.0085
The Management Fee has been restated to reflect a reduction to 0.85% of average daily net assets effective May 1, 2025.
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
117
399
703
1565
92
315
556
1248
87
286
502
1125
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 77% of the average value of its portfolio.
0.77
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its total assets in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by companies of all sizes domiciled outside the U.S. that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time. Normally, the Fund’s investments will be divided among Continental Europe, the United Kingdom, Canada, Japan and the markets of the Pacific Basin. The Fund may invest the greater of 35% of its net assets or twice the emerging markets component of the MSCI All Country World ex USA Investable Market Index (“ACWI ex USA IMI”) (net) in emerging markets, which include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1-800-635-2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1-800-635-2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn25.20% (<span class="sec-hidden" style="-sec-ix-hidden:h_534_5647d976_555d_4ac8_b3a0_dc804eabdcbe">2Q20</span>)Lowest QuarterlyReturn(19.91)% (<span class="sec-hidden" style="-sec-ix-hidden:h_537_0c8fb759_dd78_4e68_95ab_f949187ec550">1Q20</span>)
0.2520
Lowest QuarterlyReturn
-0.1991
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1774
0.0146
0.0661
0.1319
-0.0071
0.0515
0.1363
0.0096
0.0514
0.1801
0.0173
0.0691
0.3196
0.0777
0.0837
2019-05-02
2019-05-02
0.1807
0.0178
0.0743
0.3196
0.0777
0.0860
WILLIAM BLAIR INSTITUTIONAL INTERNATIONAL GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Institutional International Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0085
0
0.0006
0.0091
0.0006
0.0085
The Management Fee has been restated to reflect a reduction to 0.85% of average daily net assets effective May 1, 2025.
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
87
284
498
1114
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 79% of the average value of its portfolio.
0.79
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its total assets in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by companies of all sizes domiciled outside the U.S. that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time. Normally, the Fund’s investments will be divided among Continental Europe, the United Kingdom, Canada, Japan and the markets of the Pacific Basin. The Fund may invest the greater of 35% of its net assets or twice the emerging markets component of the MSCI All Country World ex USA Investable Market Index (“ACWI ex USA IMI”) (net) in emerging markets, which include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn25.41% (<span class="sec-hidden" style="-sec-ix-hidden: t_54_68d6e756_c697_8111_6fe9_db73dbe94fbe;">2Q20</span>)Lowest QuarterlyReturn(19.71)% (<span class="sec-hidden" style="-sec-ix-hidden: t_54_69e06451_f600_9fe9_30cb_8ccdd2e6a0f6;">1Q20</span>)
0.2541
Lowest QuarterlyReturn
-0.1971
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1805
0.0178
0.0703
0.1486
-0.0026
0.0524
0.1287
0.0120
0.0542
0.3196
0.0777
0.0837
WILLIAM BLAIR INTERNATIONAL SMALL CAP GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair International Small Cap Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0100
0.0100
0.0100
0.0025
0
0
0.0036
0.0034
0.0023
0.0161
0.0134
0.0123
0.0026
0.0024
0.0018
0.0135
0.0110
0.0105
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
137
483
852
1889
112
401
711
1592
107
373
658
1473
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 69% of the average value of its portfolio.
0.69
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in stocks of small capitalization (“small cap”) companies. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by foreign small cap companies that the Adviser believes have above-average growth, profitability and quality characteristics. For purposes of the Fund, William Blair Investment Management, LLC (the “Adviser”) considers a company to be a small cap company if it has a float adjusted market capitalization at the time of purchase no larger than the greater of $5 billion or the largest capitalized company included in the MSCI All Country World (“ACWI”) ex USA Small Cap Index (net). Securities of companies whose float adjusted market capitalizations no longer meet this definition of small cap company after purchase may continue to be held in the Fund. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time. Normally, the Fund’s investments will be divided among Continental Europe, the United Kingdom, Canada, Japan and the markets of the Pacific Basin. The Fund may invest the greater of 35% of its net assets or twice the emerging markets component of the MSCI ACWI ex USA Small Cap Index (net) in emerging markets, which include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. As of March 31, 2026, the MSCI ACWI ex USA Small Cap Index (net) included securities issued by companies that ranged in size between $41 million and $12.4 billion.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Micro Cap Company Risk.</span> Stocks of small and micro cap companies involve greater risk than those of larger, more established companies. This is because small and micro cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and micro cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and micro cap companies may be more volatile and less liquid than securities of large capitalized companies. For purposes of the Fund, micro cap are companies with market capitalizations of $500 million or less at the time of the Fund’s investment.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments).</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The MSCI All Country World ex USA Investable Market Index (“ACWI IMI”) represents a broad measure of market performance, while the MSCI ACWI ex USA Small Cap Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The MSCI All Country World ex USA Investable Market Index (“ACWI IMI”) represents a broad measure of market performance, while the MSCI ACWI ex USA Small Cap Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn29.29% (<span class="sec-hidden" style="-sec-ix-hidden: t_58_879c22c5_6b50_f820_5840_a55e2f195cc3;">2Q20</span>)Lowest QuarterlyReturn(25.05)% (<span class="sec-hidden" style="-sec-ix-hidden: t_58_6a92cd8b_e973_bd3e_80c2_de3a00c5387c;">1Q20</span>)
Highest QuarterlyReturn
0.2929
Lowest QuarterlyReturn
-0.2505
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1498
-0.0100
0.0454
0.1488
-0.0182
0.0352
0.0894
-0.0072
0.0348
0.1530
-0.0074
0.0483
0.1542
-0.0067
0.0492
0.3196
0.0777
0.0837
0.2926
0.0691
0.0813
WILLIAM BLAIR EMERGING MARKETS LEADERS FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Emerging Markets Leaders Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0.0094
0.0025
0
0
0.0035
0.0033
0.0024
0.0154
0.0127
0.0118
0.0030
0.0028
0.0024
0.0124
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
126
457
811
1809
101
375
670
1509
96
351
626
1410
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result inhigher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 79% of the average value of its portfolio.
0.79
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in emerging markets securities. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by emerging market companies of all sizes that the Adviser believes have above-average growth, profitability and quality characteristics. Under normal market conditions, the Fund typically holds a limited number of securities (<span style="font-style: italic;">i.e.</span>, 50‑80 securities). The Adviser seeks investment opportunities in companies at different stages of development, ranging from large, well-established companies to smaller companies at earlier stages of development, that are leaders in their country, industry or globally in terms of products, services or execution. Emerging market companies, for purposes of the Fund, are companies organized under the laws of an emerging market country or that have securities traded principally on an exchange or over‑the‑counter in an emerging market country. Currently, emerging markets include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of emerging market companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth at reasonable valuation levels will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms. The currencies of emerging market countries may experience a devaluation relative to the U.S. dollar, and continued devaluations may adversely affect the value of the Fund’s assets denominated in such currencies. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance. In addition, because the Fund may focus its investments in a limited number of securities, its performance may be more volatile than a fund that invests in a greater number of securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with that of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with that of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn26.29% (<span title="element: N0%, context: 10%"><span class="sec-hidden" style="-sec-ix-hidden:t_708_3833c38d_a029_5df7_e0b4_f443e82b37f6">2Q20</span></span>)Lowest QuarterlyReturn(24.36)% (<span title="element: N0%, context: 10%"><span class="sec-hidden" style="-sec-ix-hidden:t_708_135ac326_305e_bbe3_b22e_3f066fe84368">1Q20</span></span>)
0.2629
Lowest QuarterlyReturn
-0.2436
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class N shares and on a before‑tax basis for Class I and Class R6 shares. After‑tax returns for Class I and Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.2605
-0.0077
0.0635
0.2585
-0.0124
0.0582
0.1556
-0.0062
0.0504
0.2643
-0.0051
0.0664
0.2642
-0.0046
0.0668
0.3357
0.0420
0.0842
WILLIAM BLAIR EMERGING MARKETS GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Emerging Markets Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0.0094
0.0025
0
0
0.0024
0.0024
0.0011
0.0143
0.0118
0.0105
0.0019
0.0019
0.0011
0.0124
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
126
434
764
1697
101
356
631
1415
96
323
569
1273
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 84% of the average value of its portfolio.
0.84
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in emerging markets securities. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by emerging market companies of all sizes that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development. Emerging market companies, for purposes of the Fund, are companies organized under the laws of an emerging market country or that have securities traded principally on an exchange or over‑the‑counter in an emerging market country. Currently, emerging markets include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of emerging market companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms. The currencies of emerging market countries may experience a devaluation relative to the U.S. dollar, and continued devaluations may adversely affect the value of the Fund’s assets denominated in such currencies. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1-800-635-2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1-800-635-2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn30.41% (<span class="sec-hidden" style="-sec-ix-hidden: h_714_ef08d109_862f_4ea5_9d76_02476509dbb7;" title="element: N0%, context: 10%">2Q20</span>)Lowest QuarterlyReturn(20.85)% (<span class="sec-hidden" style="-sec-ix-hidden: h_717_e7c7f4c2_4c82_4ade_8658_b896860d2a19;" title="element: N0%, context: 10%">1Q20</span>)
0.3041
Lowest QuarterlyReturn
-0.2085
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares.After-tax returns for Class I and Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares.After-tax returns for Class I and Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.2484
0.0080
0.0824
0.2480
-0.0011
0.0720
0.1473
0.0059
0.0656
0.2518
0.0105
0.0852
0.2523
0.0111
0.0859
0.3138
0.0466
0.0837
WILLIAM BLAIR EMERGING MARKETS EX CHINA GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Emerging Markets ex China Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0
0
0.0092
0.0082
0.0186
0.0176
0.0087
0.0082
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
101
500
925
2109
96
474
877
2005
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 84% of the average value of its portfolio.
0.84
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in emerging markets securities, excluding companies with their principal office in the People’s Republic of China (“PRC”). (For the avoidance of doubt, the PRC shall include mainland China, Hong Kong and Macau but exclude Taiwan.) The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by emerging market companies (excluding companies with their principal office in the PRC) of all sizes that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development. Emerging market companies, for purposes of the Fund, are companies organized under the laws of an emerging market country or that have securities traded principally on an exchange or over‑the‑counter in an emerging market country. Currently, for purposes of the Fund, emerging markets include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time.In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of emerging market companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms. The currencies of emerging market countries may experience a devaluation relative to the U.S. dollar, and continued devaluations may adversely affect the value of the Fund’s assets denominated in such currencies. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span><span style="font-weight: bold;"> </span>Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span><span style="font-weight: bold;"> </span>To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the calendar years since the Fund commenced operations.
Highest QuarterlyReturn
Highest QuarterlyReturn13.97% (<span class="sec-hidden" style="-sec-ix-hidden:t_808_38eeb45a_c6ad_c303_d979_f602a8d4f7bb">4Q23</span>)Lowest QuarterlyReturn(3.56)% (<span class="sec-hidden" style="-sec-ix-hidden: t_784_a3122f1b_5a87_d19f_109f_9cb8078176f1;">3Q23</span>)
0.1397
Lowest QuarterlyReturn
-0.0356
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class I shares and on a before-tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown.<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.</div>
The table below shows returns on a before-tax and after-tax basis for Class I shares and on a before-tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
2022-07-29
2022-07-29
2022-07-29
2022-07-29
2022-07-29
0.2818
0.1688
0.2650
0.1637
0.1776
0.1335
0.2825
0.1696
0.3142
0.1541
WILLIAM BLAIR EMERGING MARKETS SMALL CAP GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Emerging Markets Small Cap Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0110
0.0110
0.0110
0.0025
0
0
0.0035
0.0033
0.0022
0.0170
0.0143
0.0132
0.0030
0.0028
0.0022
0.0140
0.0115
0.0110
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
143
506
895
1984
117
425
755
1689
112
397
702
1571
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 261% of the average value of its portfolio.
2.61
PRINCIPAL INVESTMENT STRATEGIES:
Under normal market conditions, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of emerging market small capitalization (“small cap”) companies. The Fund invests primarily in a diversified portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), issued by emerging market small cap companies that the Adviser believes have above average growth, profitability and quality characteristics. For purposes of the Fund, the Adviser considers a company to be a small cap company if it has a float adjusted market capitalization at the time of purchase no larger than the greater of $5 billion or the largest capitalized company included in the MSCI Emerging Markets Small Cap Index (net). Securities of companies whose float adjusted market capitalizations no longer meet this definition of small cap after purchase may continue to be held in the Fund. Emerging market companies, for purposes of the Fund, are companies organized under the laws of an emerging market country or that have securities traded principally on an exchange or over‑the‑counter in an emerging market country. Currently, emerging markets include every country in the world except the United States, Canada, Japan, Australia, New Zealand, Hong Kong, Singapore and most Western European countries. The Fund’s investments are normally allocated among at least six different countries and no more than 50% of the Fund’s equity holdings may be invested in securities of issuers in one country at any given time. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of emerging market companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus. Stock selection will take into account both local and global comparisons.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Adviser will vary the Fund’s sector and geographic diversification based upon the Adviser’s ongoing evaluation of economic, market and political trends throughout the world. In making decisions regarding country allocation, the Adviser will consider such factors as the conditions and growth potential of various economies and securities markets, currency exchange rates, technological developments in the various countries and other pertinent financial, social, national and political factors.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span> The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. equity securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span> The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a local currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a local currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms. The currencies of emerging market countries may experience a devaluation relative to the U.S. dollar, and continued devaluations may adversely affect the value of the Fund’s assets denominated in such currencies. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations. Many emerging market countries have experienced substantial rates of inflation for many years, and continued inflation may adversely affect the economies and securities markets of such countries.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span> To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Small and Micro Cap Company Risk.</span> Stocks of small and micro cap companies involve greater risk than those of larger, more established companies. This is because small and micro cap companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Small and micro cap companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of small and micro cap companies may be more volatile and less liquid than securities of large capitalized companies. For purposes of the Fund, micro cap companies are companies with market capitalizations of $500 million or less at the time of the Fund’s investment.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Portfolio Turnover Rate Risk.</span> Higher portfolio turnover rates involve correspondingly higher transaction costs, which are borne directly by the Fund. In addition, the Fund may realize significant short-term and long-term capital gains if portfolio turnover rate is high, which will result in taxable distributions to investors that may be greater than those made by other funds with lower portfolio turnover rates.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the growth investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The MSCI Emerging Markets Investable Markets Index (“IMI”) represents a broad measure of market performance, while the MSCI Emerging Markets Small Cap Index is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1-800-635-2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The MSCI Emerging Markets Investable Markets Index (“IMI”) represents a broad measure of market performance, while the MSCI Emerging Markets Small Cap Index is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1-800-635-2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class N shares performance has varied in each of the last ten calendar years.
Highest QuarterlyReturn
Highest QuarterlyReturn27.69% (<span><span class="sec-hidden" style="-sec-ix-hidden: t_843_e9e81869_a314_d628_3144_215adc7c9bba;">2Q20</span></span>)Lowest QuarterlyReturn(20.89)% (<span><span class="sec-hidden" style="-sec-ix-hidden: t_843_75417e45_7490_3e0d_9fb0_e7b18658e792;">1Q20</span></span>)
0.2769
Lowest QuarterlyReturn
-0.2089
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before-tax and after-tax basis for Class N shares and on a before-tax basis for Class I and Class R6 shares. After-tax returns for Class I and Class R6 shares will vary.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
0.1368
0.0441
0.0719
0.1125
0.0333
0.0638
0.0970
0.0333
0.0564
0.1394
0.0467
0.0747
0.1399
0.0473
0.0753
0.3138
0.0466
0.0837
0.1858
0.0843
0.0831
WILLIAM BLAIR CHINA GROWTH FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair China Growth Fund seeks long-term capital appreciation.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0094
0.0094
0
0
0.0760
0.0760
0.0854
0.0854
0.0755
0.0760
0.0099
0.0094
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
101
1815
3410
6929
96
1811
3407
6927
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 73% of the average value of its portfolio.
0.73
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in securities of companies with their principal office in the People’s Republic of China (“PRC”). For the avoidance of doubt, the PRC shall include mainland China, Hong Kong and Macau but exclude Taiwan. The Fund may pursue this objective through purchases of class A‑Shares of companies listed on the Shanghai and Shenzhen Stock Exchanges, H‑Shares listed in Hong Kong, American Depositary Receipts, Global Depositary Receipts and dual listed securities. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Fund invests primarily in a portfolio of equity securities, including common stocks and other forms of equity investments (e.g., securities convertible into common stocks), of companies of all sizes that the Adviser believes have above-average growth, profitability and quality characteristics. The Adviser seeks investment opportunities in companies at different stages of development ranging from large, well-established companies to smaller companies at earlier stages of development.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">In choosing investments, the Adviser performs fundamental company analysis and focuses on stock selection. The Adviser generally seeks equity securities, including common stocks, of Chinese companies that historically have had superior growth, profitability and quality relative to local markets and relative to companies within the same industry worldwide, and that are expected to continue such performance. Such companies generally will exhibit superior business fundamentals, including leadership in their field, quality products or services, distinctive marketing and distribution, pricing flexibility and revenue from products or services consumed on a steady, recurring basis. These business characteristics should be accompanied by management that is shareholder return-oriented and that uses conservative accounting policies. Companies with above-average returns on equity, strong balance sheets and consistent, above-average earnings growth will be the primary focus.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">As noted above, the Fund will invest in China A‑Shares. The Fund may do so through the Shanghai-Hong Kong and Shenzhen-Hong Kong Stock Connect Programs (“Stock Connect”). Stock Connect is a securities trading and clearing program between either the Shanghai Stock Exchange (“SSE”) or Shenzhen Stock Exchange (“SZSE”), and any of the Stock Exchange of Hong Kong Limited (“SEHK”), China Securities Depository or Clearing Corporation Limited (“ChinaClear”) and Hong Kong Securities Clearing Company Limited (“HKSCC”). Stock Connect is designed to permit mutual stock market access between mainland China and Hong Kong by allowing investors to trade and settle shares on each market via their local exchanges. Trading through Stock Connect is subject to daily quotas that limit the maximum daily net purchases on any particular day. Accordingly, the Fund’s direct investments in China A‑Shares may be limited by such daily quotas. Investments in China A‑Shares may also be made through the use of the Investment Manager’s Qualified Foreign Institutional Investor (“QFII”) license.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">THE FUND IS NON‑DIVERSIFIED UNDER THE INVESTMENT COMPANY ACT OF 1940, AS AMENDED, AND MAY INVEST A LARGER PERCENTAGE OF ITS ASSETS IN FEWER ISSUERS THAN DIVERSIFIED MUTUAL FUNDS.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Chinese Investment Risk.</span> Because the fund focuses its investments in China, the Fund’s performance is expected to be closely tied to social, political, and economic conditions in China and to be more volatile than the performance of more geographically diversified funds. Investing in Chinese investments involves a higher degree of risk and special considerations not typically associated with investing in other more established economies or</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">securities markets. The Fund’s investment exposure to China may subject the Fund, to a greater extent than if investments were made in developed countries, to the risks of adverse securities markets, exchange rates and social, political, regulatory, economic, or environmental events and natural disasters that may occur in the China region. The economy, industries, and securities and currency markets of China are particularly vulnerable to the region’s dependence on exports and international trade and increasing competition from Asia’s other low‑cost emerging economies. The imposition of tariffs or other trade barriers, trade restrictions, sanctions, or investment prohibitions by the U.S. or foreign governments on exports from China may also have an adverse impact on Chinese issuers. There is also a risk that the U.S. Government or other governments may sanction Chinese issuers or otherwise prohibit U.S. persons (such as the Fund) from investing in certain Chinese issuers, such prohibitions and sanctions may be permanent or may expand over time, which may negatively affect the liquidity and price of their securities. In addition, currency fluctuations, currency convertibility, interest rate fluctuations and higher rates of inflation as a result of internal social unrest or conflicts with other countries have had, and may continue to have, negative effects on the economies and securities markets of China. The government of the PRC exercises significant control over the economy in mainland China and may at any time alter or discontinue economic reforms. Hong Kong and Macau do not exercise the same level of control over their economies as does the PRC with respect to mainland China, but changes to their political and economic relationships with the PRC could adversely impact the Fund’s investments in Hong Kong and Macau.</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">Concerns regarding a trade war between China and the United States have triggered and may continue to trigger a significant reduction in international trade, supply chain diversification away from Chinese producers, the oversupply of certain manufactured goods, substantial price reductions of goods and possible failure of individual companies and/or large segments of China’s export industry, all of which may have a negative impact on the Fund’s investments. Events such as these and their consequences are difficult to predict and it is unclear whether further tariffs, trade restrictions, sanctions, or investment prohibitions may be imposed or other escalating actions may be taken in the future.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Investing Through Stock Connect Risk.</span> Investing in China A‑Shares through the Stock Connect program is subject to trading, clearance, settlement, and other procedures, which could pose risks to the Fund. Trading through Stock Connect is subject to market-wide trading volume and market cap quota limitations, each of which may restrict or preclude the Fund’s ability to invest in A‑Shares through Stock Connect. A primary feature of Stock Connect is the application of the home market’s laws and rules applicable to investors in A‑Shares. Therefore, the Fund’s investments in Stock Connect A‑Shares are generally subject to PRC securities regulations and listing rules, among other restrictions. Additionally, restrictions on the timing of permitted trading activity in A‑Shares, including the imposition of local holidays in either Hong Kong or mainland China and restrictions on purchasing and selling the same security on the same day, may subject the Fund to the risk of price fluctuations of China A‑Shares at times when the Fund is unable to add to or exit its position.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Equity Funds General Risk.</span><span style="font-weight: bold;"> </span>The value of equity securities the Fund holds might decrease in response to the activities of an individual company or in response to general market, business and economic conditions. If this occurs, the Fund’s share price may also decrease. In addition, there is the risk that individual securities may not perform as expected or a strategy used by the Adviser may fail to produce its intended result.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span> The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, less stringent or a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">mutual funds investing exclusively in U.S. securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span> Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. Local, regional or global events such as war, military conflict, geopolitical disputes, acts of terrorism, social unrest, tariffs and other restrictions on trade, sanctions, supply chain disruptions, increased government spending, natural disasters, the spread of infectious illness or other public health issues, or the threat or potential threat of one or more such events and developments could also significantly impact the Fund and its investments. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span><span style="font-weight: bold;"> </span>The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a non‑U.S. currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a non‑U.S. currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Focus Risk.</span> To the extent that the Fund focuses its investments in particular industries, asset classes or sectors of the economy, any market changes affecting companies in those industries, asset classes or sectors may impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span> Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Non‑Diversification Risk.</span> The Fund is non‑diversified, meaning that it is permitted to invest a larger percentage of its assets in fewer issuers than diversified mutual funds. Thus, the Fund may be more susceptible to adverse developments affecting any single issuer held in its portfolio and may be more susceptible to greater losses because of these developments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span> To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s</div><div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Smaller Company Risk.</span> Stocks of smaller companies involve greater risk than those of larger, more established companies. This is because smaller companies may be in earlier stages of development, may be dependent on a small number of products or services, may lack substantial capital reserves and/or do not have proven track records. Smaller companies may be traded in low volumes. This can increase volatility and increase the risk that the Fund will not be able to sell a security on short notice at a reasonable price. The securities of smaller companies may be more volatile and less liquid than securities of large capitalized companies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Style Risk.</span> Different investment styles (e.g., growth vs. value, quality bias, market capitalization focus) tend to shift in and out of favor depending on market conditions and investor sentiment, and at times when the investment style used by the Adviser for the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance that is generally representative of the market sectors or types of investments in which the Fund invests.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the calendar years since the Fund commenced operations.
Highest QuarterlyReturn13.32% (<span class="sec-hidden" style="-sec-ix-hidden:t_71_ade9abbe_534a_cff0_d25d_bb82d6e987fe">3Q24</span>)Lowest QuarterlyReturn(24.07)% (<span><span class="sec-hidden" style="-sec-ix-hidden:t_87_c314e3c3_4789_2ae9_28b0_5be2243168b3">3Q22</span></span>)
Highest QuarterlyReturn
0.1332
Lowest QuarterlyReturn
-0.2407
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary. After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
2021-08-27
2021-08-27
2021-08-27
2021-08-27
2021-08-27
0.2425
-0.0878
0.2400
-0.0891
0.1453
-0.0645
0.2421
-0.0881
0.2894
-0.0042
WILLIAM BLAIR EMERGING MARKETS DEBT FUND
SUMMARY
INVESTMENT OBJECTIVE:
The William Blair Emerging Markets Debt Fund seeks to provide attractive risk-adjusted returns relative to the Fund’s benchmark.
FEES AND EXPENSES:
This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Shareholder Fees (fees paid directly from your investment):
0
0
0
0
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
0.0065
0.0065
0
0
0.0053
0.0042
0.0118
0.0107
0.0048
0.0042
0.0070
0.0065
April 30, 2027
Example:
This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and the Fund’s operating expenses remain the same. The figures reflect the expense limitation for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
72
327
603
1389
66
299
549
1268
Portfolio Turnover:
The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 120% of the average value of its portfolio.
1.20
PRINCIPAL INVESTMENT STRATEGIES:
Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in debt instruments that are economically tied to emerging market countries, which may be represented by forwards or derivatives such as options, futures contracts or swap agreements. Emerging markets include every country in the world except countries included in the MSCI World Index. <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">Debt securities in which the Fund invests include fixed-rate and floating-rate bonds issued by various public (governmental) and private (corporate) issuers (including private placements and restricted securities). The Fund invests a significant portion of its assets in sovereign debt securities (debt securities issued or guaranteed by foreign sovereign governments or their agencies, authorities or political subdivisions or instrumentalities, and supranational agencies) and debt securities of quasi-sovereign issuers (entities owned by a sovereign government). The Fund may also invest in debt securities issued or guaranteed by foreign corporations and foreign financial institutions. The Fund may invest in debt securities of any credit rating, including investment grade securities, below investment grade securities (commonly referred to as “high yield” or “junk bonds”), and unrated securities. The Fund may invest up to a maximum of 10% of the Fund’s net assets in distressed or defaulted debt securities. The Fund may invest in securities of any maturity.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The majority of the Fund’s investments are generally made in securities of issuers based in South and Central America (including the Caribbean), Central Europe, Eastern Europe, Asia, Africa and the Middle East. More specifically, the Fund invests in countries where the Adviser is able to assess the specific political and economic risks and in countries that have undertaken certain economic reforms and reached certain growth objectives. Countries in which the Fund invests include frontier markets (emerging markets that are early in their development).</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Fund invests in assets denominated in the currencies of economically developed and politically stable countries that are members of the Organisation for Economic Co‑operation and Development (OECD), as well as in assets denominated in local currency. The Adviser may, but is not required to, hedge the currency risk associated with the Fund’s investments.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">As part of its investment strategy, the Fund may utilize derivatives, including futures and forward contracts, swaps (including credit default swaps and total return swaps), credit derivatives, and currency-related derivatives. Derivatives are primarily utilized to hedge interest rate duration risk and foreign exchange risk.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">Additionally, the Fund may maintain assets in cash, deposit, call or current accounts or invest in short-term instruments, such as money market funds, U.S. or other government securities, certificates of deposit, bankers’ acceptances or similar temporary investments, to meet the expense needs of the Fund and/or to fund withdrawals or for such other purposes as may be determined by the Adviser.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The Adviser measures the Fund’s performance against the JPMorgan Emerging Markets Bond Index (EMBI) Global Diversified, which is the Fund’s “benchmark” for purposes of its investment objective. The Fund is actively managed within its objective and is not constrained by a benchmark.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">THE FUND IS NON‑DIVERSIFIED UNDER THE INVESTMENT COMPANY ACT OF 1940, AS AMENDED, AND MAY INVEST A LARGER PERCENTAGE OF ITS ASSETS IN FEWER ISSUERS THAN DIVERSIFIED MUTUAL FUNDS.</div>
The Fund’s returns will vary, and you could lose money by investing in the Fund.
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Market Risk.</span> The value of the Fund’s investments may go up or down, sometimes rapidly or unpredictably. The value of an investment may decline due to factors affecting securities markets generally or particular industries represented in the securities markets. The value of an investment may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, recessions, inflation, rapid interest rate changes, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. The value of an investment may also decline due to factors that affect a particular industry or industries, such as labor shortages or increased production costs and competitive conditions within an industry. During a general downturn in the securities markets, multiple asset classes may decline in value simultaneously. Geopolitical and other events may also disrupt securities markets and adversely affect global economies and markets and thereby decrease the value of the Fund’s investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Credit Risk.</span> The value of the Fund’s fixed income securities is subject to the ability of the issuers of such securities to make interest payments or principal payment at maturity. The credit ratings of issuers could change and negatively affect the Fund’s share price or yield. The Fund’s net asset value and total return may be adversely affected by the inability of the issuers of the Fund’s securities to make interest payments or payment at maturity. The Fund’s investments in obligations issued or guaranteed by U.S. Government agencies or instrumentalities may not be backed by the full faith and credit of the United States and may differ in the degree of support provided by the U.S. Government.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Foreign Investment Risk.</span><span style="font-weight: bold;"> </span>The risks of foreign investments may include less publicly available information, less stringent investor protections and disclosure standards, less governmental regulation and supervision of foreign stock exchanges, brokers and issuers, share registration and custody, less stringent or a lack of uniform accounting, auditing and financial reporting standards, practices and requirements, the possibility of expropriation, seizure or nationalization, confiscatory taxation, limits on repatriation, adverse changes in investment or exchange control regulations, political instability, restrictions on the flow of international capital, imposition of foreign withholding or other taxes, fluctuating currencies, inflation, difficulty in obtaining and enforcing judgments against foreign entities or other adverse political, social or diplomatic developments that could affect the Fund’s investments. Foreign investments may be less liquid and their prices more volatile than the securities of U.S. companies. The Fund is expected to incur operating expenses that are higher than those of mutual funds investing exclusively in U.S. securities due to the higher custodial fees associated with foreign securities investments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Emerging Markets Risk.</span><span style="font-weight: bold;"> </span>Foreign investment risk is typically magnified in emerging markets, which are the less developed and developing nations. These risks are further magnified in frontier markets, which are among the smallest and least mature investment markets.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Sovereign and Quasi-Sovereign Default Risk.</span> The Fund invests in securities issued by or guaranteed by non‑U.S. sovereign governments (known as sovereign debt securities) and in securities issued by entities that are owned or guaranteed by non‑U.S. sovereign governments (known as quasi-sovereign debt securities). An issuer of sovereign or quasi-sovereign debt held by the Fund, or the governmental authorities that control the repayment of the debt, may be unable or unwilling to repay the principal or interest when due. This may result from political or social factors, the general economic environment of a country or levels of foreign debt or foreign currency exchange rates.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Interest Rate Risk.</span> Normally, the values of fixed income securities vary inversely with changes in prevailing interest rates. The value of the Fund’s fixed income securities tends to decrease when interest rates rise and tends to increase when interest rates fall. Securities with longer maturities or durations held by the Fund are generally more sensitive to interest rate changes. As such, securities with longer maturities or durations are usually more volatile than those with shorter maturities or durations. The negative impact on fixed income securities from</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">rising interest rates could be swift and significant and negatively impact the Fund’s net asset value. A rising interest rate environment may also result in periods of increased redemptions from fixed income funds and increased supply in the market due to selling activity to meet redemptions. If the Fund has to liquidate portfolio securities to meet redemptions in such an environment, it may have to do so at disadvantageous times and prices, which could negatively impact the Fund’s net asset value. Changing interest rates may result in heightened market volatility and may detract from Fund performance to the extent the Fund is exposed to such interest rates and/or volatility.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Aggressive Investment Technique Risk.</span><span style="font-weight: bold;"> </span>The Fund may use investment techniques and financial instruments that may be considered aggressive, including but not limited to the use of futures contracts, options on futures contracts, securities and indices, forward contracts, swap agreements and similar instruments. Such techniques may also include taking short positions or using other techniques that are intended to provide inverse exposure to a particular market or other asset class, as well as leverage, which can expose the Fund to potentially dramatic losses or gains. These techniques may expose the Fund to potentially dramatic losses in the value of certain of its portfolio holdings.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Counterparty and Contractual Default Risk.</span><span style="font-weight: bold;"> </span>The Fund’s investments in derivatives and other financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s failure or inability to perform its obligations or bankruptcy. The Fund may obtain no or limited recovery in a bankruptcy.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Credit Default Swap Risk.</span><span style="font-weight: bold;"> </span>Credit default swaps are subject to the credit risk of the underlying reference obligation and to counterparty credit risk. If the counterparty fails to meet its obligations, the Fund may lose money. Credit default swaps are also subject to the risk that the Adviser will not properly assess the risk of the underlying reference obligation. If the Fund is selling credit protection, there is a risk that a credit event will occur and that the Fund will have to pay the counterparty. If the Fund is buying credit protection, there is a risk that no credit event will occur and the Fund will receive no benefit for the premium paid. Credit default swaps may be difficult to value and may have the effect of leverage on the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Currency Risk.</span><span style="font-weight: bold;"> </span>The value of the Fund’s portfolio may be affected by changes in exchange rates or control regulations. Currency exchange rates may fluctuate significantly over short periods of time for a number of reasons, including changes in interest rates. If a non‑U.S. currency gains against the U.S. dollar, the value of the security increases in U.S. dollar terms. If a non‑U.S. currency declines against the U.S. dollar, the value of the security decreases in U.S. dollar terms.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Derivatives Risk.</span><span style="font-weight: bold;"> </span>Investing in derivatives, including futures and forward contracts, swaps, credit derivatives, and currency-related derivatives, involves investment techniques and risks different from those associated with ordinary mutual fund securities transactions and may involve increased transaction costs. The Fund’s investment in derivatives may rise or fall more rapidly in value than other investments and may reduce the Fund’s returns. Changes in the value of the derivative may not correlate perfectly, or at all, with the underlying asset, reference rate or index, and the Fund could lose more than the principal amount invested. Derivatives also may be subject to certain other risks such as leveraging risk, liquidity risk, interest rate risk, market risk, credit risk, counterparty risk, operational risk, legal risk, management risk and the risk of mispricing or improper valuation. Derivatives also may not behave as anticipated by the Fund, especially in abnormal market conditions. The use of derivatives may increase the volatility of the Fund’s net asset value. Derivatives may be leveraged such that a small investment in derivative instruments can have a significant impact on the Fund’s exposure to stock market values, interest rates, currency exchange rates or other investments. As a result, a relatively small price movement in a derivatives contract may cause an immediate and substantial loss or gain. It may be difficult or impossible for the Fund to purchase or sell certain derivatives in sufficient amounts to achieve the desired level of exposure, which may result in a loss or may be costly to the Fund. In addition, the possible lack of a liquid secondary market for certain derivatives and the resulting inability of the Fund to sell or otherwise close out a derivatives position could expose the Fund to losses and could make such derivatives more difficult for the Fund</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">to value accurately. Some derivatives are more sensitive to market price fluctuations and to interest rate changes than other investments. The Fund also could suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. The Fund also may be exposed to losses if the counterparty in the transaction does not fulfill its contractual obligation. In addition, derivatives traded over‑the‑counter (“OTC derivatives”) do not benefit from the protections provided by exchanges in the event that a counterparty is unable to fulfill its contractual obligation. Such OTC derivatives therefore involve greater counterparty and credit risk and may be more difficult to value than exchange-traded derivatives. When a derivative is used as a hedge against a position that the Fund holds, any loss generated by the derivative should generally be offset by gains on the hedged instrument, and vice versa. While hedging can reduce or eliminate losses, it also can reduce or eliminate gains. Hedges are sometimes subject to imperfect matching between the derivative and the hedged investment, and there can be no assurance that the Fund’s hedging transactions will be effective. Also, suitable derivative transactions may not be available in all circumstances. Derivatives are subject to fees and other costs which are not reflected in the Annual Fund Operating Expenses table.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">Derivatives are also subject to liquidity risk. Liquidity risk is the risk that a derivative instrument cannot be sold, closed out or replaced quickly at or very close to its fundamental value. Generally, exchange-traded derivatives are very liquid because the exchange clearinghouse is the counterparty of every contract. OTC derivatives are less liquid than exchange-traded derivatives since they often can be closed out only with the other party to the transaction. The Fund’s ability to sell or close out a position in an instrument prior to expiration or maturity depends on the existence of a liquid secondary market or, in the absence of such a market, the ability and willingness of the counterparty to enter into a transaction closing out the position. Therefore, there is no assurance that any derivatives position can be sold or closed out at a time and price that is favorable to the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Distressed Debt Risk</span><span style="font-weight: bold;"><span style="font-style: italic;">.</span></span> When the Fund invests in obligations of financially troubled companies (sometimes known as “distressed” securities), there exists the risk that the transaction involving such debt obligations will be unsuccessful, take considerable time or will result in a distribution of cash or a new security or obligation in exchange for the stressed and distressed debt obligations, the value of which may be less than the Fund’s purchase price of such debt obligations. Distressed securities may be subject to greater levels of market, credit, issuer and liquidity risks. Distressed companies may be engaged in restructurings or bankruptcy proceedings, which may cause the value of their securities to fluctuate rapidly or unpredictably. Distressed securities may also be illiquid and difficult to value accurately. Furthermore, if an anticipated transaction does not occur, the Fund may be required to sell its investment at a loss or hold its investment pending bankruptcy proceedings in the event the issuer files for bankruptcy.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Floating and Variable Rate Securities Risk.</span> For floating and variable rate securities, there may be a lag between an actual change in the underlying interest rate benchmark and the reset time for an interest payment of such a security, which could harm or benefit the Fund, depending on the interest rate environment or other circumstances. In a rising interest rate environment, for example, a floating or variable rate security that does not reset immediately would prevent the Fund from taking full advantage of rising interest rates in a timely manner. However, in a declining interest rate environment, the Fund may benefit from a lag due to a security’s interest rate payment not being immediately impacted by a decline in interest rates.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">Certain floating and variable rate securities have an interest rate floor feature, which prevents the interest rate payable by the security from dropping below a specified level as compared to a reference interest rate (the “reference rate”). Such a floor protects the Fund from losses resulting from a decrease in the reference rate below the specified level. However, if the reference rate is below the floor, there will be a lag between a rise in the reference rate and a rise in the interest rate payable by the security, and the Fund may not benefit from increasing interest rates for a significant amount of time.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Geographic Risk.</span><span style="font-weight: bold;"> </span>To the extent that the Fund invests a significant portion of its assets in any one country or geographic region, the Fund will be subject to greater risk of loss or volatility than if the Fund always maintained wide geographic diversity among the countries and geographic regions in which it invests. Investing in any one</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">country or geographic region makes the Fund more vulnerable to the risks of adverse securities markets, exchange rates and social, political, regulatory and economic events in that one country or geographic region.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Government and Regulatory Risk.</span><span style="font-weight: bold;"> </span>Future regulatory developments could impact the Fund’s ability to invest in certain derivatives. It is possible that government regulation of various types of derivative instruments, including futures, options and swap agreements, may limit or prevent the Fund from using such instruments as a part of its investment strategies, and could ultimately prevent the Fund from being able to achieve its investment objective. It is impossible to predict the effects of future legislation and regulation in this area, but the effects could be substantial and adverse. It is possible that legislative and regulatory activity could limit or restrict the ability of the Fund to use certain derivatives as a part of its investment strategies and could alter, perhaps to a material extent, the nature of an investment in the Fund or the ability of the Fund to continue to implement its investment strategies.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">High Yield Securities Risk.</span><span style="font-style: italic;"> </span>The Fund invests in instruments including junk bonds and instruments that may be issued by companies that are highly leveraged, less creditworthy or financially distressed. These investments are considered to be speculative and are subject to greater risk of loss, greater sensitivity to economic changes, valuation difficulties and potential illiquidity. Such investments are subject to additional risks including subordination to other creditors, no collateral or limited rights in collateral, lack of a regular trading market, extended settlement periods, liquidity risks, prepayment risks, and lack of publicly available information. Because some instruments may have a more limited secondary market, liquidity and valuation risk is more pronounced for the Fund than for funds that invest primarily in other types of fixed income instruments or equity securities.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Income Risk.</span><span style="font-weight: bold;"> </span>The income received by the Fund may decrease as a result of a decline in interest rates.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Leverage Risk.</span> The Fund’s investments in derivatives or exposure to derivatives through other investment vehicles expose the Fund to leverage inherent in such instruments. Such leveraged investments can amplify the effects of market volatility on the Fund’s net asset value (<span style="font-style: italic;">i.e.</span>, relatively small market movements may result in large changes in the Fund’s net asset value) and make the Fund’s returns more volatile. At times, the Fund’s leveraged investments may cause the Fund’s investment exposure to exceed its net assets and could cause the Fund to experience substantial losses, including the risk of total loss, if the market moves against the Fund. The use of leveraged investments may also cause the Fund to liquidate portfolio positions when it would not be advantageous to do so in order to satisfy its obligations. The use of leveraged investments may also cause the Fund to have higher expenses than those of mutual funds that do not use such techniques.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Liquidity Risk.</span><span style="font-weight: bold;"> </span>Investments that trade less frequently can be more difficult or more costly to buy, or to sell, than more liquid or active investments. It may not be possible to sell or otherwise dispose of illiquid securities both at the price and within a time period deemed desirable by the Fund.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Non‑Diversification Risk.</span><span style="font-weight: bold;"> </span>The Fund is non‑diversified, meaning that it is permitted to invest a larger percentage of its assets in fewer issuers than diversified mutual funds. Thus, the Fund may be more susceptible to adverse developments affecting any single issuer held in its portfolio and may be more susceptible to greater losses because of these developments.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Operational and Technology Risk.</span> Cyber-attacks, disruptions, or failures that affect the Fund’s service providers, counterparties, market participants, or issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Portfolio Turnover Rate Risk.</span><span style="font-weight: bold;"> </span>Higher portfolio turnover rates involve correspondingly higher transaction costs, which are borne directly by the Fund. In addition, the Fund may realize significant short-term and long-term capital gains if portfolio turnover rate is high, which will result in taxable distributions to investors that may be greater than those made by other funds with lower portfolio turnover rates.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Private Placement Risk.</span><span style="font-weight: bold;"> </span>Investments in private placements may be difficult to sell at the time and at the price desired by the Fund; companies making private placements may make less information available than publicly offered companies; and privately placed securities are more difficult to value than publicly traded securities. These factors may have a negative effect on the performance of the Fund. Securities acquired through private placements are not registered for resale in the general securities market and may be classified as illiquid.</div> <div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;">The futures, options and swaps markets are subject to comprehensive statutes, regulations, and margin requirements. In addition, the U.S. Securities and Exchange Commission, Commodity Futures Trading Commission and the exchanges are authorized to take extraordinary actions in the event of a market emergency, including, for example, the implementation or reduction of speculative position limits, the implementation of higher margin requirements, the establishment of daily price limits and the suspension of trading. The regulation of futures, options and swaps transactions in the United States is a changing area of law and is subject to modification by government and judicial action.</div>
<div style="margin-top: 0pt; margin-bottom: 0pt; font-size: 10pt; font-family: times new roman;"><span style="font-weight: bold;">Share Ownership Concentration Risk.</span><span style="font-weight: bold;"> </span>To the extent that a significant portion of the Fund’s shares is held by a limited number of shareholders or their affiliates, there is a risk that the share trading activities of these shareholders could disrupt the Fund’s investment strategies, which could have adverse consequences for the Fund and other shareholders (e.g., by requiring the Fund to sell investments at inopportune times or causing the Fund to maintain larger-than-expected cash positions pending acquisition of investments). In addition, separate accounts managed by the Adviser may invest in the Fund and, therefore, the Adviser at times may have discretionary authority over a significant portion of the assets of the Fund. In such instances, the Adviser’s decision to make changes to or rebalance its clients’ allocations in the separate accounts may substantially impact the Fund’s performance.</div>
FUND PERFORMANCE HISTORY:
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Bloomberg Global Aggregate Index represents a broad measure of market performance, while the performance of the JPMorgan EMBI Global Diversified is generally representative of the market sectors or types of investments in which the Fund invests. The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. For more recent performance information, go to https://im.williamblair.com/investments/mutual-funds or call 1‑800‑635‑2886.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index. The Bloomberg Global Aggregate Index represents a broad measure of market performance, while the performance of the JPMorgan EMBI Global Diversified is generally representative of the market sectors or types of investments in which the Fund invests.
The information below provides some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual total returns for the periods indicated compare with those of a broad measure of market performance and an additional index.
The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.
https://im.williamblair.com/investments/mutual-funds
1‑800‑635‑2886
Annual Total Returns.
The bar chart below provides an illustration of how the Fund’s Class I shares performance has varied in each of the calendar years since the Fund commenced operations.
Highest QuarterlyReturn10.05% (<span><span class="sec-hidden" style="-sec-ix-hidden: t_930_918d3361_d5a8_d454_b3e7_c7362a51d99d;">4Q23</span></span>)Lowest QuarterlyReturn(13.36)% (<span class="sec-hidden" style="-sec-ix-hidden: t_930_7ca550eb_56e9_bc13_1cf1_fa7223f48ff0;">2Q22</span>)
Highest QuarterlyReturn
0.1005
Lowest QuarterlyReturn
-0.1336
Average Annual Total Returns (For the periods ended December 31, 2025).
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary. After‑tax returns are calculated using the historical highest individualfederal marginal income tax rates and do not reflect the impact of state and local taxes. In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains. Actual after‑tax returns depend on an investor’s tax situation and may differ from those shown. After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
The table below shows returns on a before‑tax and after‑tax basis for Class I shares and on a before‑tax basis for Class R6 shares. After‑tax returns for Class R6 shares will vary.
After‑tax returns are calculated using the historical highest individualfederal marginal income tax rates and do not reflect the impact of state and local taxes.
In some instances, the “Return After Taxes on Distributions and Sale of Fund Shares” may be greater than the “Return Before Taxes” because the investor is assumed to be able to use the capital loss on the sale of Fund shares to offset other taxable capital gains.
After‑tax returns are not relevant to investors who hold their Fund shares through tax‑deferred arrangements, such as 401(k) plans or individual retirement accounts.
2021-05-25
2021-05-25
2021-05-25
2021-05-25
2021-05-25
2021-05-25
0.1609
0.0358
0.1313
0.0098
0.0940
0.0150
0.1616
0.0364
0.0817
-0.0182
0.1430
0.0229
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.75% and 0.70% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this contractual agreement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.95% and 0.90% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.20% of average daily net assets for Class N shares until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.24%, 0.99% and 0.94% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.85% and 0.80% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this contractual agreement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees. The Adviser is entitled to recoupment of previously waived fees and reimbursed expenses for a period of three years subsequent to the Fund’s commencement of operations (i.e. until August 17, 2026) to the extent that such recoupment does not cause the annual Fund operating expenses (after the recoupment is taken into account) to exceed both (1) the expense limit in place when such amounts were waived or reimbursed and (2) the Fund’s current expense limitation.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.24%, 0.99% and 0.94% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.15% and 0.89% of average daily net assets for Class N and Class I shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.15%, 0.90% and 0.85% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.15%, 0.90% and 0.85% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
The Management Fee has been restated to reflect a reduction to 0.85% of average daily net assets effective May 1, 2025.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.15%, 0.90% and 0.85% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
The Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement does not equal the net expense ratio to average daily net assets in the Financial Highlights section of this prospectus as a result of a change in the management fee and contractual expense limits.
The Management Fee has been restated to reflect a reduction to 0.85% of average daily net assets effective May 1, 2025.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.85% of average daily net assets for shares until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
The Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement does not equal the net expense ratio to average daily net assets in the Financial Highlights section of this prospectus as a result of a change in the management fee and contractual expense limits.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.35%, 1.10% and 1.05% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
The Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement does not equal the net expense ratio to average daily net assets in the Financial Highlights section of this Prospectus as a result of a change in the contractual expense limits.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.24%, 0.99% and 0.94% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.24%, 0.99% and 0.94% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.99% and 0.94% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this contractual agreement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.90%, 0.65% and 0.60% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 1.40%, 1.15% and 1.10% of average daily net assets for Class N, Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this arrangement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
The Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement does not equal the net expense ratio to average daily net assets in the Financial Highlights section of this Prospectus as a result of a change in contractual expense limits.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.99% and 0.94% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this contractual agreement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.
William Blair Investment Management, LLC (the “Adviser”) has entered into a contractual agreement with the Fund to waive fees and/or reimburse expenses in order to limit the Fund’s operating expenses (excluding interest expenses, taxes, brokerage commissions, acquired fund fees and expenses, dividend and interest expenses on short sales, other investment-related costs and extraordinary expenses, such as litigation and other expenses not incurred in the ordinary course of the Fund’s business) to 0.70% and 0.65% of average daily net assets for Class I and Class R6 shares, respectively, until April 30, 2027. The Adviser may not terminate this contractual agreement prior to April 30, 2027 without the approval of the Fund’s Board of Trustees.