Summary Prospectus by Investment Company - Form 497K

FPA New Income Fund
Institutional Class Shares (FPNIX)
Investor Class Shares (FPNRX)

Summary Prospectus April 30, 2024

Before you invest, you may want to review the Fund's prospectus, which contains more information about the FPA New Income Fund (the "Fund") and its risks. You can find the Fund's Statutory Prospectus and Statement of Additional Information and other information about the Fund online at https://fpa.com/funds/overview/new-income. You may also obtain this information at no cost by calling (800) 982-4372, except from Alaska, Hawaii, Puerto Rico and U.S. Virgin Islands (where you may call collect (310) 473-0225 or by sending an e-mail request to [email protected]). The Fund's Prospectus and Statement of Additional Information, both dated April 30, 2024, as each may be amended or supplemented, are incorporated by reference into this Summary Prospectus.

INVESTMENT OBJECTIVE

The Fund seeks to provide long-term total return, which includes income and capital appreciation, while considering capital preservation.

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​​First Pacific Advisors, LP (the "Adviser" or "FPA"), the Fund's investment adviser, has contractually agreed to reimburse the Fund for Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage fees and commissions payable by the Fund in connection with the purchase or sale of portfolio securities, and extraordinary expenses, including litigation expenses not incurred in the Fund's ordinary course of business) in excess of 0.45% of the average daily net assets of the Institutional Class shares of the Fund through July 27, 2024, and in excess of 0.454% of the average daily net assets of the Institutional Class shares of the Fund from July 28, 2024 through April 30, 2025, and in excess of 0.55% of the average daily net assets of the Investor Class shares of the Fund from inception through July 27, 2024, and in excess of 0.554% of the average daily net assets of the Investor Class shares of the Fund from July 28, 2024 through April 30, 2025. This

agreement may only be terminated earlier by the Fund's Board of Trustees (the "Board") or upon termination of the Advisory Agreement.

²​​Estimated for the current fiscal year.

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 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 expense reimbursement only for the term of the 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 rate 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 ended September 30, 2023, the Fund's portfolio turnover rate was 50% of the average value of its portfolio. The Fund's portfolio turnover rate may vary from year to year as well as within a year.

PRINCIPAL INVESTMENT STRATEGIES

The Fund primarily invests in a diversified portfolio of debt securities, cash and cash equivalents. The Fund generally invests in highly rated debt securities and invests at least 75% of its total assets, calculated at market value at the time of purchase, in debt securities rated at least A- or its equivalent by a nationally recognized statistical rating organization ("NRSRO") and in cash equivalent securities.

Under normal circumstances, the Fund invests primarily in the following debt securities, among others:

• Corporate bonds, municipal bonds, bank loans, bonds issued by governments and their agencies and instrumentalities, mortgage-backed pools, sovereign debt, and obligations of supra-national agencies, including international development institutions that provide global financing and advisory services for economic development.

• Structured investments, commercial mortgage-backed securities, residential mortgage-backed securities, collateralized mortgage obligations, asset-backed securities, collateralized loan obligations, collateralized debt obligations and structured notes. The Fund may invest a significant portion of its portfolio in these investments.

• Cash equivalent securities, which may include publicly traded securities issued by the U.S. government or agencies of the U.S. government, money market funds, certificates of deposit, commercial paper, repurchase agreements, bankers' acceptances and other similar short-term bonds.

The Fund may invest up to 25% of its total assets, calculated at market value at the time of purchase, in debt securities that are rated below A- or its equivalent by an NRSRO, which may include securities that are in default, or that are unrated.

The Fund may also invest up to 25% of its total assets, calculated at market value at the time of purchase, in securities of non-U.S. governments and corporations, non-U.S. structured investments or in securities that are not denominated in U.S. dollars; and up to 15% of its total assets, calculated at market value at the time of purchase, in stripped mortgage securities (such as interest-only and principal-only classes of collateralized mortgage obligations), collateralized mortgage obligations structured as accrual certificates, also known as Z-Bonds, and inverse floating rate debt instruments.

The Fund may also invest up to 5% of its total assets, calculated at market value at the time of purchase, in preferred stocks.

The Fund may hold investments in common stocks and rights to purchase common stocks. Such investments are typically received as a result of a conversion, corporate restructuring or recapitalization. Further, common stocks may be purchased as a result of exercising such rights, or purchased to increase an existing investment in common stocks. The Fund may also hold investments in privately placed securities.

The Fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. The Fund may also invest in currency forwards, swaps and other certain currency derivatives, in each case for hedging purposes only.

PRINCIPAL RISKS

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.

Interest Rate Risk. As with most funds that invest in debt securities, changes in interest rates are one of the most important factors that could affect the value of an investment in the Fund. Interest rate risk is the risk that debt securities will decline in value because of increases in interest rates. Rising interest rates tend to cause the prices of debt securities (especially those with longer maturities) and the Fund's share price to fall. When interest rates rise from a low level, fixed income securities markets may experience lower prices, increased volatility and lower liquidity. The negative impact on fixed income securities from rate increases, regardless of the cause, could be swift and significant, which could result in significant losses by the Fund, even if such rate increases are anticipated by the portfolio manager.

Market Risk. The market price of investments owned by the Fund may go up or down, sometimes rapidly or unpredictably. Fund investments may decline in value due to factors affecting the overall markets, or particular industries or sectors. The value of a holding may decline due to general market conditions that are not specifically related to a particular issuer, such as real or perceived adverse economic conditions, changes in the general outlook for an issuer's financial condition, national or international political events, war, acts of terrorism, inflation/deflation, market disruptions, public health emergencies, such as the spread of infectious illness or disease, natural disasters, changes in interest or currency rates, domestic or international monetary policy or adverse investor sentiment generally. The value of a holding may also decline due to factors that affect a particular industry or industries, such as competitive conditions within an industry or government regulations. The Fund may experience heavy redemptions that could cause the Fund to liquidate its assets at inopportune times or at a loss or depressed value, which could cause the value of an investment in the Fund to unexpectedly decline. Shareholder redemptions may also cause the Fund to engage in "odd-lot" fixed-income transactions, which due to their small size, may result in the Fund receiving substantially lower value on such transactions than if the Fund had engaged in a large block trade of such securities. In addition, the Fund may rely on various third-party sources to calculate its net asset value. Errors or systems failures and other technological issues may adversely impact the Fund's calculation of its net asset value, and such net asset value calculation issues may result in inaccurately calculated net asset values, delays in net asset value calculation and/or the inability to calculate net asset values over extended periods. The Fund may be unable to recover any losses associated with such failures.

Mortgage-Related and Asset-Backed Securities Risk. Mortgage-related and other asset-backed securities represent interests in "pools" of mortgages or other assets such as consumer loans or receivables held in trust and often involve risks that are different from or possibly more acute than risks associated with other types of debt instruments. Mortgage-related securities, including commercial mortgage-backed securities ("CMBS") and residential mortgage-backed securities ("RMBS") are subject to prepayment risk and can be highly sensitive to changes in interest rates. Mortgage-backed securities, and in particular those not backed by a government guarantee, are subject to credit risk. The Fund's investments in other asset-backed securities are subject to risks similar to those associated with mortgage-related securities, as well as additional risks associated with the nature of the assets and the servicing of those assets.

Stripped Securities Risk. Stripped securities are more volatile than securities for which the principal and interest payments have not been separated. The value of stripped securities generally fluctuates more in response to interest rate movements than the value of traditional bonds because a change in interest rates may increase or decrease prepayments of principal. The market for stripped securities may be limited, which may make it difficult for the Fund to dispose of them quickly at an acceptable price.

Credit Risk. Credit risk refers to the likelihood that an issuer will default on the payment of principal and/or interest on a security. Various factors could affect the issuer's actual or perceived willingness or ability to make timely interest or principal payments, including changes in the issuer's financial condition or in general economic conditions.

Call Risk. Issuers of callable bonds are permitted to redeem these bonds before their final maturity. If an issuer calls a security in which the Fund is invested, the Fund could lose potential price appreciation and be forced to reinvest the proceeds in securities that bear a lower interest rate or more credit risk.

Liquidity Risk. The Fund's investments in illiquid securities may reduce the returns of the Fund because it may not be able to sell the illiquid securities at an advantageous time or price.

Large Investor Risk. Ownership of shares of the Fund may be concentrated in one or a few large investors. Such investors may redeem shares in large quantities or on a frequent basis. Redemptions by a large investor may affect the performance of the Fund, may increase realized capital gains, may accelerate the realization of taxable income to shareholders and may increase transaction costs. These transactions potentially limit the use of any capital loss carryforwards and certain other losses to offset future realized capital gains (if any). Such transactions may also increase the Fund's expenses. In addition, the Fund may be delayed in investing new cash after a large shareholder purchase, and under such circumstances may be required to maintain a larger cash position than it ordinarily would.

Management Risk. The Fund is subject to management risk as an actively managed investment portfolio. The portfolio manager will apply investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that these will produce the desired results. The portfolio manager's opinion about the intrinsic worth or creditworthiness of a company or security may be incorrect, the portfolio manager may not make timely purchases or sales of securities for the Fund, the Fund's investment objective may not be achieved, or the market may continue to undervalue the Fund's securities. In addition, the Fund may not be able to quickly dispose of certain securities holdings. The frequency of trading within the Fund impacts portfolio turnover rates, which are shown in the financial highlights table. A higher rate of portfolio turnover could produce higher trading costs and taxable distributions, which would detract from the Fund's performance. Moreover, there can be no assurance that all of the Adviser's personnel will continue to be associated with the Adviser for any length of time. The loss of services of one or more key employees of the Adviser, including the Fund's portfolio manager, could have an adverse impact on the Fund's ability to achieve its investment objective. Certain securities or other instruments in which the Fund seeks to invest may not be available in the quantities desired. In such circumstances, the portfolio manager may determine to purchase other securities or instruments as substitutes. Such substitute securities or instruments may not perform as intended, which could result in losses to the Fund.

Private Placements and Restricted Securities Risk. Private placement securities are securities that are not registered under the federal securities laws, and are generally eligible for sale only to certain eligible investors. The Fund may invest in securities that are purchased in private placements. Because there may be relatively few potential purchasers for such investments, especially under adverse market or economic conditions or in the event of adverse

changes in the financial condition of the issuer, the Fund could find it more difficult to sell such securities when FPA believes it advisable to do so or may be able to sell such securities only at prices lower than if such securities were more widely held. At times, it may also be more difficult to determine the fair value of such securities for purposes of computing the net asset value of the Fund. The sale of such investments may also be restricted under securities laws.

U.S. Government Securities Risk. Certain U.S. government securities are supported by the full faith and credit of the United States; others are supported by the right of the issuer to borrow from the U.S. Treasury; others are supported by the discretionary authority of the U.S. government to purchase the agency's obligations; and still others are supported only by the credit of the issuing agency, instrumentality, or enterprise. Although U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal National Mortgage Association (Fannie Mae) may be chartered or sponsored by Congress, they are not funded by Congressional appropriations, and their securities are not issued by the U.S. Treasury, are not supported by the full faith and credit of the U.S. government, and involve increased credit risks in comparison to U.S. Treasury securities or other securities supported by the full faith and credit of the U.S. government.

Risks Associated with Investing in High Yield Securities. High yield bonds, which are sometimes called "junk" bonds, are highly speculative securities that are usually issued by smaller, less credit-worthy and/or highly leveraged (indebted) companies. High yield securities are generally subject to greater levels of credit, call and liquidity risks than higher-rated securities of similar maturity. In addition, such securities may, under certain circumstances, be less liquid than higher rated securities. These securities pay investors a premium (a high interest rate or yield) because of the potential illiquidity and increased risk of loss. These securities can also be subject to greater price volatility. In times of unusual or adverse market, economic or political conditions, these securities may experience higher than normal default rates.

Risks Associated with Investing in Repurchase Agreements. A repurchase agreement is a short-term investment. The Fund acquires a debt security that the seller agrees to repurchase at a future time and set price. If the seller declares bankruptcy or defaults, the Fund may incur delays and expenses liquidating the security. The security may also decline in value or fail to provide income.

Sovereign Debt Risk. An issuer of sovereign debt or the governmental authorities that control the repayment of the debt may be unable or unwilling to repay principal or interest when due. In the event of a default by a governmental entity on a sovereign debt obligation, there may be few or no effective legal remedies for collecting on such debt.

Risks Associated with Investing in Non-U.S. Securities. Non-U.S. investments involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. The prices of non-U.S. 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 non-U.S. 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. Emerging markets tend to be more volatile than the markets of more mature economies and generally have less diverse and less mature economic structures and less stable political systems than those of developed countries.

Risks Associated with Deep Discount Securities. The high yield securities in which the Fund may invest may from time to time include debt securities of companies that are financially troubled, in default or are in bankruptcy or reorganization. These securities are called "deep discount securities" and are deeply discounted from their face value. A debt instrument purchased at a deep discount, but prior to default, may pay a very high effective yield. If the issuer cannot meet its debt obligations, however, the deep discount securities may stop generating income and lose its value or become worthless. A lack of reliable, objective data or market quotations may make it more difficult to value deep discount securities accurately. Insufficient liquidity in the deep discount security market may make it more difficult to dispose of such securities and may cause the Fund to experience sudden and substantial price declines.

Adjustable Rate Mortgage ("ARM") Risk. During periods of extreme fluctuations in interest rates, the resulting fluctuations of ARM rates could affect the ARMs' market value. Most ARMs generally have annual reset limits or "caps." Fluctuations in interest rates above these levels, thus, could cause the mortgage-backed securities to "cap out" and to behave more like long-term, fixed- rate debt securities. During periods of declining interest rates, of course, the coupon rates may readjust downward and result in lower yields.

Currency Transactions Risk. Currency hedging involves many risks such as leveraging risk, market risk, liquidity risk, counterparty risk, management risk, operational risk and legal risk. Currency derivative transactions are also subject to risks different from those of other derivative transactions and can be adversely affected by changes to government controls, limitations or restrictions on repatriation of currency, and manipulations or exchange restrictions imposed by governments and based on broader factors extrinsic to any particular country's economy. There can be no assurance that currency transactions or currency hedging techniques will be successful.

Over-the-Counter ("OTC") Investments Risk. Securities and derivatives traded in OTC markets may trade in smaller volumes, and their prices may be more volatile, than securities principally traded on securities exchanges. Such securities may be less liquid than more widely traded securities. In addition, the prices of such securities may include an undisclosed dealer markup, which the Fund pays as part of the purchase price.

Cybersecurity Risk. Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, customer data (including private shareholder information), or proprietary information, or cause the Fund, the adviser and/or other service providers (including custodians, sub-custodians, transfer agents and financial intermediaries) to suffer data breaches, data corruption or loss of operational functionality. In an extreme case, a shareholder's ability to exchange or redeem Fund shares may be affected. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of those securities could decline if the issuers experience cybersecurity incidents.

PERFORMANCE

The Fund acquired the assets and liabilities of FPA New Income, Inc. (the "Predecessor Fund") following the reorganization of the Predecessor Fund on July 28, 2023. As a result of the acquisition, the Fund is the accounting successor of the Predecessor Fund. Performance results shown in the bar chart and the performance table below for periods prior to July 28, 2023, reflect the performance of the Predecessor Fund.

The bar chart and Average Annual Total Returns table below provide an 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 for the 1, 5 and 10 calendar year periods compare with those of a broad-based securities market index and with a measure of the change in cost of living plus 100 basis points. The past performance information shown below is for Institutional Class shares of the Fund. Although Institutional Class shares would have similar annual returns to Investor Class shares because the classes are invested in the same portfolio of securities, the returns for Investor Class shares will vary from Institutional Class shares because of the higher expenses paid by Investor Class shares. The chart and table reflect the reinvestment of dividends and distributions. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

The Bloomberg U.S. Aggregate Bond Index is a market capitalization-weighted index, meaning the securities in the index are weighted according to the market size of each bond type. Most U.S. traded investment grade bonds are represented. Municipal bonds and Treasury Inflation-Protected Securities are excluded, due to tax treatment issues. The index includes Treasury securities, Government agency bonds, mortgage-backed bonds, corporate bonds, and a small amount of non-U.S. bonds traded in the U.S. CPI + 100 is a measure of the consumer price index ("CPI") plus an additional 100 basis points. The CPI is calculated by taking price changes for each item in the predetermined basket of goods and averaging them; the goods are weighted according to their importance. Changes in CPI are used to assess price changes associated with the cost of living.

To obtain updated monthly performance information, please visit the Fund's website at https://fpa.com/funds or call (800) 982-4372.

Calendar Year Total Return (before taxes) for Institutional Class
For each calendar year at NAV

The Fund's year-to-date return as of March 31, 2024, was 0.86%.

The Fund's highest/lowest quarterly results during this time period were:

Institutional Class

Highest 3.79% (Quarter ended 12/31/2023)

Lowest (1.74)% (Quarter ended 03/31/2022)

¹​ 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 upon an investor's tax situation and may differ from those shown. After-tax returns presented here are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts ("IRAs"). Early withdrawal from a 401(k) account or an IRA could lead to taxation of the withdrawn amount as ordinary income and could be subject to an additional tax penalty. The after-tax returns on distributions and sale of Fund shares may be higher than returns before taxes due to the effect of a tax benefit an investor may receive from the realization of capital losses that would have been incurred on the sale of Fund shares.

²​ Investor Class shares commenced operations on April 30, 2024. The performance figures for Investor Class shares include the performance for the Institutional shares for the periods prior to the inception date of Investor Class shares, adjusted for the difference in Institutional Class shares and Investor Class shares expenses. Investor Class shares impose higher expenses than Institutional Class shares. Since Investor Class shares have higher expenses and are more expensive than Institutional Class shares, the returns for Investor Class shares will be lower than the returns of the Institutional Class shares.

MANAGEMENT

Investment Adviser

First Pacific Advisors, LP is the Fund's investment adviser.

Portfolio Managers

Abhijeet Patwardhan, Partner of the Adviser, is primarily responsible for the day-to-day management of the Fund's portfolio. Mr. Patwardhan has served as the portfolio manager of the Fund since July 2023 and as the portfolio manager of the Predecessor Fund since November 2015.

PURCHASE AND SALE OF FUND SHARES

Investors may purchase or redeem Fund shares on any business day by written request, check, wire, ACH (Automated Clearing House), telephone, or through dealers as further described in this prospectus. You may conduct transactions by mail (FPA Funds, c/o UMB Fund Services, Inc., P.O. Box 2175, Milwaukee, Wisconsin 53201-2175, or 235 West Galena Street, Milwaukee, Wisconsin 53212), by wire, or by telephone at (800) 638-3060. Purchases and redemptions by telephone are only permitted if you previously established this option in your account. Investors can use the Account Application for initial purchases.

Investors can purchase shares by contacting any investment dealer authorized to sell the Fund's shares. The minimum initial investment is $1,500 for the Institutional Class Shares and Investor Class Shares, and each subsequent investment, which can be made directly to UMB Fund Services, Inc., must be at least $100. However, as described herein, no minimum investment amount is imposed for subsequent investments in retirement plans. All purchases made by check should be in U.S. dollars and made payable to the FPA Funds. Third party, starter or counter checks will not be accepted. A charge may be imposed if a check does not clear. The Fund reserves the right to waive or lower purchase and investment minimums in certain circumstances. For example, the minimums listed above may be waived or lowered for investors who are customers of certain financial intermediaries that hold the Fund's shares in certain omnibus accounts, at the discretion of the officers of the Fund. In addition, financial intermediaries may impose their own minimum investment and subsequent purchase amounts.

Subsequent investments and redemptions can be made directly to UMB Fund Services, Inc.

Notice to Non-U.S. Resident Individual Shareholders. The Fund and its shares are only registered in the United States and its territories ("United States"). Regulations outside of the United States may restrict the sale of shares to certain non-U.S. residents or subject certain shareholder accounts to additional regulatory requirements. As a result, individuals resident outside the United States are generally not eligible to invest in the Fund. The Fund reserves the right, however, to sell shares to certain other non-U.S. investors in compliance with applicable law. If a current shareholder of the Fund provides a non-U.S. address, this will be deemed a representation and warranty from such investor that he/she is not a U.S. resident and will continue to be a non-U.S. resident unless and until the Fund is notified of a change in the investor's resident status. Any current shareholder that has a resident address outside of the United States may be restricted from purchasing additional shares.

TAX INFORMATION

The Fund's distributions are taxable and will be taxed as ordinary income and/or long-term capital gain, unless you are investing through a tax-deferred arrangement, such as an IRA or 401(k) plan.

INFORMATION REGARDING TRANSACTIONS THROUGH FINANCIAL INTERMEDIARIES

Shareholders may be required to pay a commission directly to their broker or other financial intermediary when buying or selling shares of the Fund. Shareholders and potential investors may wish to contact their broker or other

financial intermediary for information regarding applicable commissions, transaction fees or other charges associated with transactions in shares of the Fund.

In addition, brokers, dealers, banks, trust companies and other financial representatives may receive compensation from the Fund or its service providers for providing a variety of services, which may include recordkeeping, transaction processing for shareholders' accounts and certain shareholder services not currently offered to shareholders that deal directly with the Fund. 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 web site for more information.