Summary Prospectus by Investment Company - Form 497K

THIS ETF IS DIFFERENT FROM TRADITIONAL ETFs

Traditional ETFs tell the public what assets they hold each day. This ETF will not. This may create additional risks for your investment. For example:

The differences between this ETF and other ETFs may also have advantages. By keeping certain information about the ETF secret, this ETF may face less risk that other traders can predict or copy its investment strategy. This may improve the ETF's performance. If other traders are able to copy or predict the ETF's investment strategy, however, this may hurt the ETF's performance.

For additional information regarding the unique attributes and risks of this ETF, see the later discussion on the Proxy Portfolio and the "Proxy Portfolio Structure Risk," "Authorized Participant Concentration Risk,""Predatory Trading Practices Risk," "Premium/Discount Risk," and "Trading Issues Risk" below.

Before you invest, you may want to review the Fund's Prospectus, which contains more information about the Fund and its risks. You can find the Fund's Prospectus and other information about the Fund online at im.natixis.com/us/etfs/natixis-loomis-sayles-focused-growth-etf/LSGR. You can also get this information at no cost by calling 800-458-7452 or by sending an e-mail request to [email protected]. The Fund's Prospectus and Statement of Additional Information, each dated May 1, 2024, as may be revised or supplemented from time to time, are incorporated by reference into this Summary Prospectus.

Investment Goal

The Fund's investment goal is long-term growth of capital.

Fund Fees & Expenses

The following 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 this table.

Annual Fund Operating Expenses

1

Fund Summary

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated (whether or not shares are redeemed), and also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same, except that the example is based on the Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement assuming that such waiver and/or reimbursement will only be in place through the date noted above and on the Total Annual Fund Operating Expenses for the remaining periods. The example does not take into account brokerage commissions and other fees to financial intermediaries that you may pay on your purchases and sales of shares of the Fund. It also does not include the transaction fees on purchases and redemptions of creation units ("Creation Units"), because those fees will not be imposed on retail investors. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

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 rate may indicate higher transaction costs and may result in higher taxes for you if your 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. For the period from the Fund's commencement of operations on June 29, 2023 through December 31, 2023, the Fund's portfolio turnover rate was 4% of the average value of its portfolio.

Investments, Risks and Performance

Principal Investment Strategies

Under normal market conditions, the Fund will invest primarily in exchange-traded U.S.-listed common stocks and other exchange-traded equity securities. Exchange-traded equity securities may include, for example, other exchange-traded funds ("ETFs"), exchange-traded notes, exchange-traded preferred stocks, and exchange-traded real estate investment trusts ("REITs"). The Fund focuses on stocks of large-capitalization companies, but the Fund may invest in companies of any size. The Fund normally invests across a wide range of sectors and industries. The Fund is non-diversified, which means that it may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers than a diversified fund. The Fund's portfolio will hold approximately 20 to 30 securities.

The Fund's portfolio manager employs a growth style of equity management that emphasizes companies with sustainable competitive advantages versus others, long-term structural growth drivers that will lead to above-average future cash flow growth, attractive cash flow returns on invested capital, and management teams focused on creating long-term value for shareholders. The Fund's portfolio manager aims to invest in companies when they trade at a significant discount to the estimate of intrinsic value (i.e., companies with share prices trading significantly below what the portfolio manager believes the share price should be based on proprietary discount cash flow models). The Fund will consider selling a portfolio investment when the portfolio manager believes an unfavorable structural change occurs within a given business or the markets in which it operates, a critical underlying investment assumption is flawed, when a more attractive reward-to-risk opportunity becomes available, when the portfolio manager believes the current price fully reflects intrinsic value, or for other investment reasons which the portfolio manager deems appropriate. Although certain equity securities purchased by the Fund may be issued by domestic companies incorporated outside of the United States, Loomis, Sayles & Company, L.P. ("Loomis Sayles" or the "Subadviser") does not consider these securities to be foreign securities if they are included in the U.S. equity indices published by S&P Global Ratings or Russell Investments or if the security's country of risk defined by Bloomberg is the United States.

Non-Transparent ETF with Proxy Portfolio Structure. The Fund is a type of exchange traded fund ("ETF"). Unlike traditional ETFs, however, which generally publish their portfolio holdings on a daily basis, the Fund discloses a portfolio transparency substitute-the "Proxy Portfolio"-and certain related information about the relative performance of the Proxy Portfolio and the Fund's actual portfolio ("Actual Portfolio") holdings (the "Proxy Portfolio Disclosures"), which are intended to help keep the market price of the Fund's shares trading at or close to the underlying net asset value ("NAV") per share of the Fund. While the Proxy Portfolio includes some of the Fund's holdings, it is not the Fund's Actual Portfolio, and the Fund will not disclose the daily holdings of the Actual Portfolio. Although the Fund seeks to benefit from keeping its portfolio information secret, market participants may attempt to use the Proxy Portfolio to identify the Fund's trading strategy, which if successful, could result in such market participants engaging in certain predatory trading practices that may have the potential to harm the Fund and its shareholders. The Fund's exemptive relief limits the types of securities in which the Fund can invest, which may constrain the Fund's ability to implement its investment strategies. The Fund is actively-managed and does not intend to track an index.

Principal Investment Risks

The principal risks of investing in the Fund are summarized below. The Fund does not represent a complete investment program. You may lose money by investing in the Fund.

2

Fund Summary

Fund shares are not bank deposits and are not guaranteed, endorsed or insured by the Federal Deposit Insurance Corporation or any other government agency, and are subject to investment risks, including possible loss of the principal invested.

The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund's portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund.

Proxy Portfolio Structure Risk: Unlike traditional ETFs that provide daily disclosure of their portfolio holdings, the Fund does not disclose the daily holdings of the Actual Portfolio. Instead, the Fund discloses a Proxy Portfolio daily that is designed to reflect the economic exposure and risk characteristics of the Fund's Actual Portfolio on any given trading day. Although the Proxy Portfolio and Proxy Portfolio Disclosures are intended to provide authorized participants ("Authorized Participants") and other market participants with enough information to allow them to engage in effective arbitrage transactions that will keep the market price of the Fund's shares trading at or close to the underlying NAV per share of the Fund, while at the same time enabling them to establish cost-effective hedging strategies to reduce risk, there is a risk that market prices will vary significantly from the underlying NAV of the Fund. See "Premium/Discount Risk." Similarly, shares of the Fund may trade at a wider bid/ask spread than shares of traditional ETFs, and may therefore be more costly for investors to trade. See "Trading Issues Risk." Also, the Fund will incur expenses to license the Proxy Portfolio mechanism, which may impact shareholder returns. Additionally, the proxy mechanism itself may result in additional trading costs, which also may negatively impact shareholder returns. In addition, although the Proxy Portfolio is designed to protect the Fund from predatory practices such as front-running and free-riding, market participants may nevertheless be able to use the Proxy Portfolio and Proxy Portfolio Disclosures to engage in trading practices that disadvantage the Fund. See "Predatory Trading Practices Risk." The Fund will monitor on an ongoing basis the premium/discount between the market price and the NAV of the Fund's shares, but there can be no assurance that the Proxy Portfolio methodology will operate as intended. The Proxy Portfolio methodology is relatively novel and may not be an effective arbitrage mechanism under all market conditions. Similarly, the Proxy Portfolio methodology may be more prone to operational error than more traditional ETFs. The effectiveness of the Proxy Portfolio methodology as an arbitrage mechanism is contingent upon, among other things, the effectiveness of the Fund's Factor Model analysis in creating a Proxy Portfolio that performs in a manner substantially identical to the performance of the Fund's Actual Portfolio and the willingness of Authorized Participants and other market participants to trade based on the Proxy Portfolio. In the event that the Proxy Portfolio methodology does not result in effective arbitrage opportunities in the Fund shares, the Fund may exhibit wider premiums/discounts, bid/ask spreads and tracking error. At certain thresholds for such premiums/discounts, bid/ask spreads and tracking error, the Fund's Board of Trustees will consider possible remedial measures, which may include liquidation or conversion to a fully-transparent, active ETF or a mutual fund.

3

Fund Summary

Equity Securities Risk: The value of the Fund's investments in equity securities could be subject to unpredictable declines in the value of individual securities and periods of below-average performance in individual securities or in the equity market as a whole. In the event an issuer is liquidated or declares bankruptcy, the claims of owners of the issuer's bonds generally take precedence over the claims of those who own preferred stock or common stock. Securities of real estate-related companies and exchange-traded REITs in which the Fund may invest may be considered equity securities, thus subjecting the Fund to the risks of investing in equity securities generally.

Liquidity Risk: Liquidity risk is the risk that the Fund may be unable to find a buyer for its investments when it seeks to sell them or to receive the price it expects. Decreases in the number of financial institutions willing to make markets in the Fund's investments or in their capacity or willingness to transact may increase the Fund's exposure to this risk. Events that may lead to increased redemptions, such as market disruptions or increases in interest rates, may also negatively impact the liquidity of the Fund's investments when it needs to dispose of them. Markets may become illiquid quickly. If the Fund is forced to sell its investments at an unfavorable time and/or under adverse conditions in order to meet redemption requests, such sales could negatively affect the Fund. During times of market turmoil, there may be no buyers or sellers for securities in certain asset classes. In other circumstances, liquid investments may become illiquid. Liquidity issues may also make it difficult to value the Fund's investments. The Fund may invest in liquid investments that become illiquid due to financial distress, or geopolitical events such as sanctions, trading halts or wars.

Management Risk: A strategy used by the Fund's portfolio manager may fail to produce the intended result.

Market/Issuer Risk: The market value of the Fund's investments will move up and down, sometimes rapidly and unpredictably, based upon overall market and economic conditions, as well as a number of reasons that directly relate to the issuers of the Fund's investments, such as management performance, financial condition and demand for the issuers' goods and services.

Market Trading Risk: The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares or the Fund's underlying portfolio securities, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Any of these factors, among others, may lead to the Fund's shares trading at a premium or discount to NAV. Accordingly, if a shareholder purchases Fund shares at a time when the market price is at a premium to the NAV, or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses.

Non-Diversification Risk: Compared with diversified ETFs, the Fund may invest a greater percentage of its assets in a particular issuer and may invest in fewer issuers. Therefore, the Fund may have more risk because changes in the value of a single security or the impact of a single economic, political or regulatory occurrence may have a greater adverse impact on the Fund's NAV.

Cybersecurity and Technology Risk: The Fund, its service providers, market makers, listing exchange, Authorized Participants and other market participants increasingly depend on complex information technology and communications systems, which are subject to a number of different threats and risks that could adversely affect the Fund and its shareholders. Cybersecurity and other operational and technology issues may result in financial losses to the Fund and its shareholders.

REITs Risk: Investments in the real estate industry, including REITs, are particularly sensitive to economic downturns and are sensitive to factors such as changes in real estate values, property taxes and tax laws, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents and the management skill and creditworthiness of the issuer. Companies in the real estate industry also may be subject to liabilities under environmental and hazardous waste laws. In addition, the value of a REIT is affected by changes in the value of the properties owned by the REIT or mortgage loans held by the REIT. REITs are also subject to default and prepayment risk. Many REITs are highly leveraged, increasing their risk. The Fund will indirectly bear its proportionate share of expenses, including management fees, paid by each REIT in which it invests in addition to the expenses of the Fund.

Secondary Market Trading Risk: Investors buying or selling shares of the Fund in the secondary market will pay brokerage commissions or other charges imposed by broker-dealers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of shares.

Small- and Mid-Capitalization Companies Risk: Compared to large-capitalization companies, small- and mid-capitalization companies are more likely to have limited product lines, markets or financial resources. Stocks of these companies often trade less frequently and in limited volume and their prices may fluctuate more than stocks of large-capitalization companies. As a result, it may be relatively more difficult for the Fund to buy and sell securities of small- and mid-capitalization companies.

New and Smaller Sized Fund Risk:The Fund is relatively new and has a limited operating history for investors to evaluate and may not be successful in implementing its investment strategies. The Fund may fail to attract sufficient assets to achieve or maintain economies of scale, which could result in the

4

Fund Summary

Fund being liquidated at any time without shareholder approval and at a time that may not be favorable for all shareholders. Smaller ETFs will have a lower public float and lower trading volumes, leading to wider bid/ask spreads.

Operational Risk: The Fund is exposed to operational risk arising from a number of factors, including but not limited to human error, processing and communication errors, errors of the Fund's service providers, market makers, listing exchange, Authorized Participants or the issuers of securities in which the Fund invests or with which they do business, failed or inadequate processes and technology or systems failures.

Risk/Return Bar Chart and Table

Because the Fund has not yet completed a full calendar year, information related to Fund performance, including a bar chart showing annual returns, has not been included in this Prospectus. The performance information provided by the Fund in the future will give 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 returns compare to those of a broad-based securities market index that reflects the performance of the overall market applicable to the Fund and an additional index that represents the market sectors in which the Fund primarily invests. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available online at im.natixis.com and/or by calling the Fund toll-free at 800-458-7452.

Management

Investment Adviser

Natixis Advisors

Subadviser

Loomis Sayles

Portfolio Manager

Loomis Sayles

Aziz V. Hamzaogullari, CFA^®, Chief Investment Officer of the Growth Equities Strategies Team, Executive Vice President and Director at Loomis Sayles, has served as manager of the Fund since 2023.

Purchase and Sale of Fund Shares

The Fund will issue and redeem shares at NAV only in large blocks of shares, typically 10,000 shares, called "Creation Units." Only a few financial institutions that are Authorized Participants are authorized to purchase and redeem Creation Units directly with the Fund. Creation Units are typically issued and redeemed in exchange for cash and/or the deposit or delivery of a basket of securities specified each day by the Fund as the securities in exchange for which the Fund will issue or redeem shares. Except when aggregated in Creation Units, shares are not redeemable securities of the Fund. The number of shares comprising a Creation Unit may change from time to time.

Individual shares of the Fund may only be purchased and sold in secondary market transactions through broker-dealers. Shares of the Fund are listed for trading on the NYSE Arca, and because shares trade at market prices rather than NAV, shares of the Fund may trade at a price greater than NAV (a premium) or less than NAV (a discount).

You may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market ("the bid/ask spread"). For more information, including recent information (when available) regarding the Fund's NAV, market price, premiums and discounts, and bid/ask spreads, please visit the Fund's website at im.natixis.com.

Tax Information

Fund distributions are generally taxable to you as ordinary income or capital gains, except for distributions to retirement plans and other investors that qualify for tax-advantaged treatment under U.S. federal income tax law generally. Investments through such tax-advantaged plans will generally be taxed only upon withdrawal of monies from the tax-advantaged arrangement.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies expect in the future to pay the intermediary for the sale of the Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

UFG77-0524