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 Statement of Additional Information (“SAI”) and other information about the Fund online at https://www.im.natixis.com/us/mutual-funds/vaughan-nelson-international-fund/ADVLX. You may also obtain this information at no cost by calling 1-888-660-6610 or by sending an e-mail request to vnfunds@vaughannelson.com. The Fund’s Prospectus and SAI, both dated February 28, 2025, as each may be amended or supplemented, are incorporated by reference into this Summary Prospectus.

Investment Objective

The investment objective of the Vaughan Nelson International Fund (the “International Fund” or “Fund”) is to seek long term capital appreciation.

Fees and Expenses of the Fund

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 table and example below.

1      Restated to reflect the current operating expense limitation agreement with the Fund’s advisor.

2      The Fund’s advisor has contractually agreed to waive its fees and/or pay for operating expenses of the Fund to ensure that total annual fund operating expenses (excluding any taxes, leverage interest, brokerage commissions, dividend and interest expenses on short sales, acquired fund fees and expenses (as determined in accordance with

Form N-1A), professional fees related to services for the collection of foreign tax reclaims, expenses incurred in connection with any merger or reorganization, and extraordinary expenses such as litigation expenses) do not exceed 1.14% and 0.89% of the average daily net assets of the Investor Class shares and Institutional Class shares, respectively. This agreement is in effect through March 1, 2026, and it may be terminated before that date only by the Trust’s Board of Trustees. The Fund’s advisor is permitted to seek reimbursement from the Fund, subject to certain limitations, of fees waived or payments made to the Fund for a period ending three full fiscal years after the date of the waiver or payment. This reimbursement may be requested from the Fund if the reimbursement will not cause the Fund’s annual expense ratio to exceed the lesser of (a) the expense limitation in effect at the time such fees were waived or payments made, or (b) the expense limitation in effect at the time of the reimbursement.

Example

This example is intended to help you compare the cost of investing in 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 that the Fund’s operating expenses remain the same. The example reflects the Fund’s contractual fee waiver and/or expense reimbursement for the term of the contractual fee waiver and/or expense reimbursement.

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 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 205% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund will invest at least 80% of its net assets (including amounts borrowed for investment purposes) in international equity securities. The Fund considers international equities to be equity securities of companies that are listed, domiciled, or conduct a meaningful amount of business outside of the United States. The Fund’s advisor defines companies conducting a meaningful amount of business outside of the United States as those companies that derive at least 50% of revenues or net profits from, or have at least 50% of assets or production capacities outside of the United States. Investments in companies that move above or below the capitalization range of the MSCI All-Country World Index ex-USA may continue to be held by the Fund in the Fund advisor’s sole discretion. Typically, the Fund’s portfolio will hold 20 to 40 securities. The Fund may invest in companies with any market capitalization. From time to time, the Fund may have a significant portion of its assets in one or more market sectors.

The Fund’s advisor uses a bottom-up approach, employing both fundamental research and quantitative tools, that seeks to identify companies with attractive valuations. The strategy invests in stocks that it believes are undervalued, relative to their intrinsic value over time. The Fund’s investments in equity securities may include common stocks, preferred stocks, real estate investment trusts (“REITs”) or other trusts, exchange-traded funds (“ETFs”), convertible securities and American, European and Global Depositary Receipts (“ADRs,” “EDRs,” and “GDRs,” respectively). ADRs are receipts that represent interests in foreign securities held on deposit by U.S. banks. EDRs and GDRs have the same qualities as ADRs, except that they may be traded in several international trading markets. The Fund may also invest in ETFs that invest in portfolios of securities designed to track particular market segments or indices and the shares of which are

bought and sold on securities exchanges. The Fund invests primarily in equity securities of foreign (non-U.S.) companies located in developed countries but may also invest in emerging markets. The Fund generally will invest in securities of companies located in different countries and regions. From time to time, the Fund may have a significant portion of its assets invested in the securities of companies in one or a few countries or regions.

Principal Risks of Investing

Risk is inherent in all investing and you could lose money by investing in the Fund. A summary description of certain principal risks of investing in the Fund is set forth below. Before you decide whether to invest in the Fund, carefully consider these risk factors associated with investing in the Fund, which may cause investors to lose money. There can be no assurance that the Fund will achieve its investment objective.

Market Risk.    The market price of a security or instrument may decline, sometimes rapidly or unpredictably, due to general market conditions that are not specifically related to a particular company, such as real or perceived adverse economic, political or geopolitical conditions throughout the world, changes in the general outlook for corporate earnings, changes in interest or currency rates, or adverse investor sentiment generally.

The market value of a security or instrument also may decline because of factors that affect a particular industry or industries, such as tariffs, labor shortages or increased production costs and competitive conditions within an industry. In addition, local, regional or global events such as war, acts of terrorism, international conflicts, trade disputes, supply chain disruptions, cybersecurity events, the spread of infectious illness or other public health issues, natural disasters or climate events, or other events could have a significant impact on a security or instrument. The increasing interconnectivity between global economies and financial markets increases the likelihood that events or conditions in one region or financial market may adversely impact issuers in a different country, region or financial market.

Equity Risk.    The value of the equity securities held by the Fund may fall due to general market and economic conditions, perceptions regarding the industries in which the issuers of securities held by the Fund participate, or factors relating to specific companies in which the Fund invests.

Foreign Investment Risk.    The prices of foreign securities may be more volatile than the prices of securities of U.S. issuers because of economic and social conditions abroad, political developments, and changes in the regulatory environments of foreign countries. Changes in exchange rates and interest rates, and the imposition of sanctions, confiscations, trade restrictions (including tariffs) and other government restrictions by the United States and/or other governments may adversely affect the values of the Fund’s foreign investments. Foreign companies are generally subject to different legal and accounting standards than U.S. companies, and foreign financial intermediaries may be subject to less supervision and regulation than U.S. financial firms. Foreign securities include ADRs, EDRs and GDRs. Unsponsored ADRs and GDRs are organized independently and without the cooperation of the foreign issuer of the underlying securities, and involve additional risks because U.S. reporting requirements do not apply. In addition, the issuing bank may deduct shareholder distribution, custody, foreign currency exchange, and other fees from the payment of dividends.

Currency Risk.    The values of investments in securities denominated in foreign currencies increase or decrease as the rates of exchange between those currencies and the U.S. dollar change. Currency conversion costs and currency fluctuations could erase investment gains or add to investment losses. Currency exchange rates can be volatile and are affected by factors such as general economic conditions, the actions of the United States and foreign governments or central banks, the imposition of currency controls, and speculation.

Emerging Markets Risk.    Many of the risks with respect to foreign investments are more pronounced for investments in issuers in developing or emerging market countries. Emerging market countries tend to have more government exchange controls, more volatile interest and currency exchange rates, less market regulation, and less developed and less stable economic, political and legal systems than those of more developed countries. There may be less publicly available and reliable information about issuers in emerging markets than is available about issuers in more developed markets. In addition, emerging market countries may experience high levels of inflation and may have less liquid securities markets and less efficient trading and settlement systems.