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Harbor Long-Short Equity ETF Investment Risks - Harbor Long-Short Equity ETF
Oct. 31, 2025
Large Cap Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Large Cap Risk: Large cap stocks may fall out of favor relative to small or mid cap stocks, which may cause the Fund to underperform other equity funds that focus on small or mid cap stocks. Large cap companies may be less able than smaller cap companies to adapt to changing market conditions and may be more mature and subject to more limited growth potential than smaller cap companies.
Mid Cap Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Mid Cap Risk: The Fund’s performance may be more volatile because it invests in mid cap stocks. Mid cap companies may have limited product lines, markets and financial resources. Securities of mid cap companies are usually less stable in price and less liquid than those of larger, more established companies. Additionally, mid cap stocks may fall out of favor relative to small or large cap stocks, which may cause the Fund to underperform other equity funds that focus on small or large cap stocks.
Short Sales Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Short Sales Risk: If the price of securities sold short increases, the Fund would be required to pay more to replace the borrowed securities than the Fund received on the sale of the securities. Because there is theoretically no limit to the amount of the increase in price of the borrowed securities, the Fund’s risk of loss on a short sale is potentially unlimited if the Fund misperceived or misjudged the relevant securities’ value. Short sales involve what is referred to as counterparty risk or the risk that a loss may be sustained as a result of the failure or inability of the broker-dealer through which the Fund made the short sale (the “counterparty”) to comply with the terms of the contract.
Model Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Model Risk: There are limitations inherent in every quantitative model. The value of securities selected using quantitative analysis can react differently to issuer, political, market, and economic developments than the market as a whole or securities selected using only fundamental analysis. The factors used in quantitative analysis and the weight placed on those factors may not be predictive of a security’s value. In addition, historical trends in data may not be predictive going forward. The strategies and techniques employed in a quantitative model cannot fully match the complexity of the financial markets and therefore sudden unanticipated changes in underlying market conditions can significantly impact their performance. The effectiveness of the given strategy or technique may deteriorate in an unpredictable fashion for any number of reasons including, but not limited to, an increase in the amount of assets managed or the use of similar strategies or techniques by other market participants and/or market dynamic shifts over time. In addition, factors that affect a security’s value can change over time, and these changes may not be reflected in the quantitative model. Any model may contain flaws the existence and effect of which may be discovered only after the fact or not at all. There can be no assurances that the strategies pursued or the techniques implemented in the quantitative model will be profitable, and various market conditions may be materially less favorable to certain strategies than others. Even in the absence of flaws, a model may not perform as anticipated.
Equity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Equity Risk: The values of equity securities may decline due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic conditions, changes in the general outlook for corporate earnings, changes in interest or currency rates or adverse investor sentiment generally. They 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. Equity securities generally have greater price volatility than fixed income securities.
Market Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Market Risk: Securities markets are volatile and can decline significantly in response to adverse market, economic, political, regulatory or other developments, which may lower the value of securities held by the Fund, sometimes rapidly or unpredictably. Events such as war, military conflict, geopolitical disputes, acts of terrorism, social or political unrest, natural disasters, recessions, inflation, rapid interest rate changes, supply chain disruptions, tariffs and other restrictions on trade, sanctions, the spread of infectious illness or other public health threats, or the threat or potential of one or more such events and developments, could also significantly impact the Fund and its investments.
Risks Associated with Exchange-Traded Funds [Member]  
Prospectus [Line Items]  
Risk [Text Block] Risks Associated with Exchange-Traded Funds: As an ETF, the Fund is subject to the following risks: Authorized Participant Concentration/Trading Risk: Only authorized participants (“APs”) may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as APs and such APs have no obligation to submit creation or redemption orders. Consequently, there is no assurance that APs will establish or maintain an active trading market for the shares. This risk may be heightened to the extent that securities held by the Fund are traded outside a collateralized settlement system. In that case, APs may be required to post collateral on certain trades on an agency basis (i.e., on behalf of other market participants), which only a limited number of APs may be able to do. In addition, to the extent that APs exit the business or are unable to proceed with creation and/or redemption orders with respect to the Fund and no other AP is able to step forward to create or redeem Creation Units (as defined below), this may result in a significantly diminished trading market for shares, and shares may be more likely to trade at a premium or discount to the Fund’s net asset value and to face trading halts and/or delisting. Further, AP concentration risk may be heightened for a fund that invests in securities issued by non-U.S. issuers or instruments with lower trading volume. Such assets often entail greater settlement and operational complexity and higher capital costs for APs, which may limit the number of APs that engage with the fund. This risk may be heightened during periods of volatility or market disruptions. Cash Transactions Risk: The Fund may effect some or all of its creations and redemptions for cash rather than in-kind. As a result, an investment in the Fund may be less tax-efficient than an investment in an ETF that effects all of its creations and redemptions in-kind. Because the Fund may effect redemptions for cash, it may be required to sell portfolio securities in order to obtain the cash needed to distribute redemption proceeds. A sale of portfolio securities may result in capital gains or losses and may also result in higher brokerage costs. To the extent costs are not offset by transaction fees charged by the Fund to APs, the costs of cash transactions will be borne by the Fund. Premium/Discount Risk: The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. This may result in the Fund’s shares trading significantly above (premium) or below (discount) the Fund’s net asset value, which will be reflected in the intraday bid/ask spreads and/or the closing price of shares as compared to net asset value. However, given that shares can only be purchased and redeemed in Creation Units to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value.
Commodity Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Commodity Risk: The Fund has exposure to commodities through investments in commodity-linked derivative instruments. Commodity prices are generally affected by, among other factors, the cost of producing, transporting and storing commodities, changes in consumer or commercial demand for commodities, the hedging and trading strategies of producers and consumers of commodities, speculative trading in commodities by commodity pools and other market participants, disruptions in commodity supply, weather, political and other global events, global economic factors and government intervention in or regulation of the commodity or commodity futures markets. The Fund may concentrate its assets in a particular sector of the commodities market (such as oil, metal or agricultural products) in order to seek to track the Index. As a result, the Fund may be more susceptible to risks associated with those sectors.
Derivatives Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Derivatives Risk: The value of derivative instruments held by the Fund may not change in the manner expected by the Subadvisor and/or Advisor, as applicable, which could result in disproportionately large losses to the Fund. Derivatives may also be more volatile than other instruments and may create a risk of loss greater than the amount invested. In addition, certain derivatives may be difficult to value and may be illiquid.
Foreign Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk: Because the Fund may invest in securities of foreign issuers, an investment in the Fund is subject to special risks in addition to those of U.S. securities. These risks include heightened political and economic risks, greater volatility, currency fluctuations, higher transaction costs, delayed settlement, possible foreign controls on investment, possible sanctions by governmental bodies of other countries and less stringent investor protection and disclosure standards of foreign markets. Foreign securities are sometimes less liquid and harder to value than securities of U.S. issuers. These risks are more significant for issuers in emerging market countries. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market.
High Portfolio Turnover Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] High Portfolio Turnover Risk: Higher portfolio turnover may adversely affect Fund performance by increasing Fund transaction costs and may lead to the realization and distribution to shareholders of higher capital gains, which may increase a shareholder’s tax liability.
Industry Group Focus Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Industry Group Focus Risk: Because the Fund may, from time to time, be more heavily invested in particular industry groups, the value of its shares may be especially sensitive to factors and economic risks that specifically affect those industry groups. As a result, the Fund’s share price may fluctuate more widely than the value of shares of a registered fund that invests in a broader range of industry groups.
Issuer Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Issuer Risk: An adverse event affecting a particular issuer in which the Fund is invested, such as an unfavorable earnings report, may depress the value of that issuer’s securities, sometimes rapidly or unpredictably.
Large Shareholder Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Large Shareholder Risk: Certain large shareholders including authorized participants (“AP”), third-party investors, the Advisor, the Subadvisor, affiliates of the Advisor or the Subadvisor, market makers, or other entities, including funds or accounts over which the Advisor or the Subadvisor, an affiliate of the Advisor or the Subadvisor or a third-party intermediary has investment discretion, such as those investing through one or more model portfolios, may from time to time own or control a substantial amount of the Fund’s shares. There is no requirement that these shareholders maintain their investment in the Fund. There is a risk that such large shareholders or that the Fund’s shareholders generally may redeem all or a substantial portion of their investments in the Fund in a short period of time, including as a result of an asset allocation decision made by the Advisor, the Subadvisor, an affiliate of the Advisor or Subadvisor or a third-party intermediary, which could have a significant negative impact on the Fund’s NAV, liquidity, and brokerage costs. Large redemptions could also result in tax consequences to shareholders and impact the Fund’s ability to implement its investment strategy. In addition, transactions by large shareholders may account for a large percentage of the trading volume on the listing exchange and may, therefore, have a material upward or downward effect on the market price of the shares.
Leveraging Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Leveraging Risk: The Fund’s use of certain investments, such as derivative instruments or reverse repurchase agreements, and certain other transactions, such as securities purchased on a when-issued, delayed delivery or forward commitment basis, buy backs and dollar rolls, can give rise to leverage within the Fund’s portfolio, which could cause the Fund’s returns to be more volatile than if leverage had not been used.
New Fund Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] New Fund Risk: There can be no assurance that the Fund will grow to or maintain an economically viable size, in which case the Board of Trustees may determine to liquidate the Fund. The Board of Trustees may liquidate the Fund at any time in accordance with the Declaration of Trust and governing law. As a result, the timing of the Fund’s liquidation may not be favorable.
Precious Metals Investment Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Precious Metals Investment Risk: Prices of precious metals, including gold and silver, and of precious metal-related financial instruments historically have been very volatile and may fluctuate sharply over short periods of time. The high volatility of precious metals prices may adversely affect the prices of financial instruments that derive their value from the price of underlying precious metals. The production and sale of precious metals by governments or central banks or other larger holders can be affected by various economic, financial, social and political factors, which may be unpredictable and may have a significant impact on the prices of precious metals.
Selection Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] Selection Risk: The Subadvisor’s judgment about the attractiveness, value and growth potential of a particular security may be incorrect, which may cause the Fund to underperform. Additionally, the Subadvisor and/or Advisor, as applicable, potentially will be prevented from executing investment decisions at an advantageous time or price as a result of domestic or global market disruptions, particularly disruptions causing heightened market volatility and reduced market liquidity, as well as increased or changing regulations.  Thus, investments that a Subadvisor and/or Advisor, as applicable, believes represent an attractive opportunity or in which the Fund seeks to obtain exposure may be unavailable entirely or in the specific quantities or prices sought by a Subadvisor and/or Advisor, as applicable, and the Fund may need to obtain the exposure through less advantageous or indirect investments or forgo the investment at the time.
U.S. Government Securities Risk [Member]  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk: Securities issued or guaranteed by U.S. government agencies or government-sponsored entities may not be backed by the full faith and credit of the U.S. government. As a result, no assurance can be given that the U.S. government will provide financial support to these securities or issuers (such as securities issued by the Federal National Mortgage Association, or the Federal Home Loan Mortgage Corporation). Although certain government securities are backed by the full faith and credit of the U.S. government (such as securities issued by the Government National Mortgage Association), circumstances could arise that would delay or prevent the payment of interest or principal. It is possible that issuers of U.S. government securities will not have the funds to meet their payment obligations in the future and, in these circumstances, the Fund’s returns may be adversely affected.
Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] This means that you could lose money on your investment in the Fund or the Fund may not perform as well as other investment options.