The fund is designed to achieve positive total return relative to the performance of the Bloomberg Commodity Index Total Return ("BCOM Index"). Total return consists of capital appreciation and income. The fund intends to invest its assets directly and indirectly in a combination of commodity-linked derivative instruments, including commodity-linked notes, futures, options and swap agreements, and fixed income securities. The fund gains exposure to commodities markets by investing through the Subsidiary and in structured notes linked to the BCOM Index, other commodity indices, or the value of a particular commodity or commodity futures contract or subset of commodities or commodity futures contracts. The value of these investments will rise or fall in response to changes in the underlying index or commodity.

The fund may invest up to 25% of its total assets in the Subsidiary, a wholly-owned subsidiary of the fund organized under the laws of the Cayman Islands. The fund will invest in the Subsidiary primarily to gain exposure to the commodities markets within the limitations of the federal tax laws, rules and regulations that apply to regulated investment companies. Generally,

the Subsidiary will invest in commodity-linked derivative instruments, but it will also invest in fixed income instruments, including U.S. government securities, U.S. government agency securities, corporate bonds, debentures and notes, mortgage-backed and other asset-backed securities, event-linked bonds, loan participations, bank certificates of deposit, fixed time deposits, bankers' acceptances, commercial paper and other short-term fixed income securities. The primary purpose of the fixed income instruments held by the Subsidiary will be to serve as collateral for the Subsidiary's derivative positions; however, these instruments are also expected to earn income for the Subsidiary.

The fund invests in a portfolio of fixed income securities normally having an average duration of one year or less, and emphasizes investment-grade fixed income securities.

The fund expects to engage in active and frequent trading of derivatives.

The accompanying bar chart and table provide an indication of the risks of investing in the fund. The bar chart shows you how performance of the fund's Class A shares has varied from year to year for up to 10 years. The table compares the fund's performance (before and after taxes) over time to that of a broad-based securities market index (i.e., a regulatory index). The fund's regulatory index is the Bloomberg US Aggregate Bond Index. The fund's regulatory index is shown in connection with certain regulatory requirements to provide a broad measure of market performance. The table also compares the fund's performance to the BCOM Index, which is currently composed of futures contracts on 25 physical commodities. The after-tax returns are shown for Class A shares only. The after-tax returns of other classes

will vary. As with all mutual funds, past performance (before and after taxes) is not a prediction of future performance.

The fund makes updated performance available at the fund's website (https://us-fund.ubs.com/en/home) or by calling Credit Suisse Funds at 877-870-2874.

Sales charges are not reflected in the accompanying bar chart, and if those charges were included, returns would be less than those shown.

•  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. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRA").

Commodity exposure risks: The fund's and the Subsidiary's investments in commodity-linked derivative instruments may subject the fund to greater volatility than investments in traditional securities, particularly if the instruments involve leverage. The value of commodity-linked derivative instruments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, livestock disease, embargoes, tariffs

and international economic, political and regulatory developments.

Use of leveraged commodity-linked derivatives creates an opportunity for increased return but, at the same time, creates the possibility for greater loss (including the likelihood of greater volatility of the fund's net asset value), and there can be no assurance that the fund's use of leverage will be successful.

Derivatives risk: Derivatives are financial contracts whose value depends on, or is derived from, the value of an underlying asset, reference rate or index. The fund typically uses derivatives as a substitute for taking a position in the underlying asset and/or as part of a strategy designed to reduce exposure to other risks, such as interest rate risk. The fund also may use derivatives for leverage. The fund's use of derivative instruments, particularly commodity-linked derivatives, involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional investments. Derivatives are subject to a number of risks described elsewhere in this Prospectus, such as commodity exposure risks, correlation risk, credit risk, illiquidity risk, interest rate risk, leveraging risk, and market risk. Also, suitable derivative transactions may not be available in all circumstances and there can be no assurance that the fund will engage in these transactions to reduce exposure to other risks when that would be beneficial.

Structured note risk: The value of a structured note will be influenced by time to maturity, level of supply and demand for the type of note, interest rate and market volatility, changes in the issuer's credit rating, and economic, legal, political, or geographic events that affect the reference asset. In addition, there may be a lag between a change in the value of the underlying reference asset and the value of the structured note.

Fixed income risk: The market value of fixed income investments will change in response to interest rate changes and other factors, such as changes in the effective maturities and credit ratings of fixed income investments. During periods of falling interest rates, the values of outstanding fixed income securities and related financial instruments generally rise. Conversely, during periods of rising interest rates, the values of such securities and related financial instruments generally decline. Fixed income investments are also subject to credit risk.

Correlation risk: Changes in the value of a hedging instrument may not match those of the investment being hedged. In addition, certain of the fund's commodity-linked derivative investments may result in the fund's performance diverging from the BCOM Index, perhaps materially. For example, a structured note can be structured to limit the loss or the gain on the investment, which would result in the Fund not participating in declines or increases in the BCOM Index that exceed the limits.

Exposure risk: The risk associated with investments (such as derivatives) or practices that increase the amount of money the fund could gain or lose on an investment.

•  Speculative To the extent that a derivative or practice is not used as a hedge, the fund is directly exposed to its risks. Gains or losses from speculative positions in a derivative may be much greater than the derivative's original cost. For example, potential losses from commodity-linked notes or swap agreements and from writing uncovered call options are unlimited.

Interest rate risk: Changes in interest rates may cause a decline in the market value of an investment. With bonds and other fixed income instruments, a rise in interest rates typically causes a fall in values, while a fall in interest rates typically causes a rise in values. Changing interest rates may have unpredictable effects on markets, may result in heightened market volatility, and could negatively impact the fund's performance. Generally, the longer the maturity or duration of a debt instrument, the greater the impact of a change in interest on the instrument's value. In periods of market volatility, the market values of fixed income securities may be more sensitive to changes in interest rates.

Market risk: The market value of an instrument may fluctuate, sometimes rapidly and unpredictably. These fluctuations, which are often referred to as "volatility," may cause an instrument to be worth less than it was worth at an earlier time. Market risk may affect a single issuer, industry, commodity, sector of the economy, or the market as a whole. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, natural disasters, recessions, or other events could have a significant impact on the fund and its investments. Market risk is common to most investments—including stocks, bonds and commodities—and the mutual funds that invest in them. The performance of "value" stocks and "growth" stocks may rise or decline under varying market conditions—for example, value stocks may perform well under circumstances in which growth stocks in general have fallen.

Bonds and other fixed income securities generally involve less market risk than stocks and commodities. However, the risk of bonds can vary significantly depending upon factors such as the issuer's creditworthiness and a bond's maturity. The bonds of some companies may be riskier than the stocks of others.

Tax risk: In order to qualify as a Regulated Investment Company (a "RIC") under the Internal Revenue Code of 1986, as amended (the "Code"), the fund must meet certain requirements regarding the source of its income, the diversification of its assets and the distribution of its income. The Internal Revenue Service has issued a ruling that income realized directly from certain types of commodity-linked derivatives would not be qualifying income. As a result, the fund's ability to realize income from direct investments in such commodity-linked derivatives as part of its investment strategy would be limited to a maximum of 10% of its gross income. To comply with the ruling, the fund seeks to gain exposure to the commodity markets primarily through investments in the Subsidiary, which invests in commodity-linked swaps, commodity futures and other derivatives, and directly through investments in commodity-linked notes. If the fund fails to qualify as a RIC, the fund will be subject to federal income tax on its net income at regular corporate rates (without reduction for distributions to shareholders). When distributed, that income also would be taxable to shareholders as an ordinary dividend to the extent attributable to the fund's earnings and profits. If the fund were to fail to qualify as a RIC and became subject to federal income tax, shareholders of the fund would be subject to diminished returns. The fund anticipates treating income and gain from the Subsidiary and from commodity-linked notes as qualifying income.