The Fund seeks to maximize both current income and total return, consistent with prudent investment and principal protection management.

Below are the fees and expenses that you would 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.

The 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 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 were those reflected in the table, inclusive of any fee waivers and/or expense reimbursements.

The Fund invests primarily in a diversified portfolio of bonds and other fixed-income securities. These include, but are not limited to, investment grade corporate bonds; U.S. or non-U.S.-government and government-related obligations (such as, U.S. treasury securities); below investment-grade corporate bonds; agency and non-agency mortgage backed-securities; asset-backed securities; senior loans (such as, leveraged loans, bank loans, covenant lite loans, and/or floating rate loans); assignments; restricted securities (e.g., Rule 144A securities); and other fixed and floating rate instruments. Under normal market conditions, the Fund invests at least 80% of its net assets (plus borrowings made for investment purposes) in bonds and other fixed-income securities, and other investments that the Adviser believes have similar economic characteristics, including other investment companies that provide investment exposure to such securities. The Adviser may shift the level of these allocations among the different bond and other fixed-income asset classes depending on market conditions.

Under normal market conditions, the Fund invests at least 25% of its assets in investment-grade fixed-income securities and may invest up to 35% of its

assets in below investment-grade fixed-income securities (commonly known as “high-yield” or “junk bonds”). The Fund considers fixed-income securities to be investment-grade if, at the time of investment, they are rated Baa3 or higher by Moody’s Investors Service (“Moody’s”), BBB- or higher by S&P Global Ratings (“S&P”) or Fitch Ratings, Inc., or equivalently rated by any other nationally recognized statistical rating organization (“NRSRO”). The Fund considers fixed-income securities to be below investment-grade if, at the time of investment, they are rated Ba1 or lower by Moody’s, BB+ or lower by S&P or Fitch, or equivalently rated by any NRSRO. If all three NRSROs provide a rating, the Adviser assigns the middle rating of Moody’s, S&P and Fitch. When a rating is available from only two agencies, the lower rating is used; if only one agency rates a bond, that rating is assigned. The Fund may also invest in unrated fixed income securities. If the Adviser determines that an unrated fixed income security is of similar quality to a rated below investment grade security (rated Ba1 or lower by Moody’s, BB+ or lower by S&P or Fitch, the Adviser will consider such unrated fixed income security to be below investment grade. If the Adviser determines that an unrated fixed income security is of similar quality to a rated investment grade security (rated Baa3 or higher by Moody’s, or BBB- or higher by S&P or Fitch), the Adviser will consider such unrated fixed income security to be investment grade. The Fund invests in senior loans that are typically rated below investment-grade and to bear interest at a floating rate that periodically resets. The Fund may also invest up to 10% of its net assets in defaulted corporate securities.

In seeking to achieve the objectives of the Fund, the Adviser may purchase securities on a when-issued basis and purchase or sell delayed-delivery securities. In addition, the Fund may invest in fixed income securities structured as fixed rate debt; floating rate debt; and debt that may not pay interest at the time of issuance. The Fund may also invest in inverse floaters, as well as interest-only and principal-only securities.

The Fund will prioritize differentiation through bottom-up, single-security selection across the major fixed income asset classes with a secondary focus on top-down asset allocation and interest rate and duration management. When selecting individual securities, the Adviser uses a bottom-up approach and seeks relative price appreciation by selecting securities the Adviser believes to be undervalued based on research and fundamental analysis and by making gradual adjustment in the average duration of the Fund’s portfolio. The Adviser’s investment strategy is a bottom-up process that first looks for opportunities by focusing on an individual issuer’s default risk pricing and then incorporates top-down considerations such as interest rate forecasting, curve selection, and other macros factors.

The Adviser utilizes an investment approach that considers a quantitative valuation model combined with a qualitative ratings framework. The Fund’s portfolio selection process uses a ranking structure with a defined “buy” and “sell” discipline that allocates investments among a list of approved issuers and considers an individual investment’s risk reward profile, legal structure, and/or downside risk, among other factors. The Adviser actively manages the portfolio’s asset class exposure using a top-down view of sector fundamentals.

The Adviser rotates Fund portfolio assets among sectors in various markets in an effort to maximize return.

Under normal market conditions, the Adviser seeks to maintain an investment portfolio with a weighted average effective duration of no less than two years and no more than eight years. The duration of the Fund’s portfolio may vary materially from its target, from time to time, and there is no assurance that the duration of the Fund’s portfolio will meet its target.

The Fund may hold cash or short-term debt securities from time to time and for temporary defensive purposes.

The Fund may invest in derivative instruments, such as futures, forwards (including forward foreign currency contracts), and swap agreements (including credit default swaps, interest rate swaps, and total return swaps), for a variety of purposes, including, but not limited to, managing the Fund’s duration or its exposure to fixed income securities with different maturities, currencies, interest rates, individual issuers, or sectors. The Fund may also use options, including, but not limited to, buying and selling (writing) put and call options on individual stocks and indexes, when such use is desirable because of tax or other considerations.

In deciding which fixed income securities to buy and sell, the Adviser attempts to emphasize securities issued by companies with strong fundamentals and relatively limited anticipated volatility. These securities are selected with the same bottom-up investment process that underpins all of the Oakmark funds. The Fund uses a value investment philosophy in selecting its securities. This value investment philosophy, in the context of fixed-income securities, is based upon the belief that, over time, a company’s credit default risk will converge with the Adviser’s estimate of the credit default risk associated with a company’s intrinsic value. By “intrinsic value,” the Adviser means its estimate of the value a knowledgeable buyer would pay to acquire the entire business. The Adviser believes that investing in securities that have credit risk priced significantly below what it believes the company’s intrinsic value implies, allows the best opportunity to achieve the Fund’s investment objective.

In an effort to achieve its goal, the Fund may engage in active and frequent trading. The Fund’s investment objective may be changed without shareholder approval. The Fund will not alter its policy to invest at least 80% of its net assets (plus borrowings made for investment purposes) in bonds and other fixed-income securities, and other investments that the Adviser believes have similar economic characteristics, including other investment companies that provide investment exposure to such securities, without providing shareholders at least 60 days’ notice. This test is applied at the time the Fund invests; later percentage changes caused by a change in Fund assets, market values or company circumstances will not require the Fund to dispose of a holding.

The bar chart and performance table below can help you evaluate the potential risk and reward of investing in the Fund by showing changes in the performance of the Fund’s Institutional Class Shares from year to year. The Fund’s past performance (before and after taxes), as provided by the bar chart and performance table that follow, is not an indication of how the Fund will perform in the future. The performance table illustrates the volatility of the Fund’s historical returns over various lengths of time and shows how the Fund’s average annual returns compare with those of a broad measure of market performance. The index, which is described in “Descriptions of Indices” in the prospectus, has characteristics relevant to the Fund’s investment strategy. The Fund’s Advisor Class and Institutional Class each commenced operations on June 10, 2020, the R6 Class commenced operations on December 15, 2020 and the Investor Class commenced operations on January 28, 2022. Updated performance information is available on Oakmark.com or by calling 1-800-OAKMARK (625-6275).

Since 2020, the highest and lowest quarterly returns for the Fund's Institutional Class Shares were:
• Highest quarterly return: 7.1%, during the quarter ended December 31, 2023
• Lowest quarterly return: -5.7%, during the quarter ended June 30, 2022

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. After-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans, qualified plans, education savings accounts or individual retirement accounts. In some cases, the after-tax returns may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of Fund shares at the end of the measurement period. After-tax returns are shown only for Institutional Class Shares. After-tax returns for Advisor Class Shares, and R6 Class Shares will vary from returns shown for Institutional Class Shares.

Credit Risk. Credit risk is the risk the issuer or guarantor of a debt security will be unable or unwilling to make timely payments of interest or principal or to otherwise honor its obligations.

Interest Rate Risk. The Fund’s yield and share price will fluctuate in response to changes in interest rates and there is a risk of loss due to changes in interest rates. In general, the prices of debt securities rise when interest rates fall, and the prices fall when interest rates rise. Inverse floaters earn interest at rates that vary inversely to changes in short-term interest rates. An inverse floater produces less income (and may produce no income) and may decline in value when market rates rise.

Government-Sponsored Entity Securities Risk. Some securities issued or guaranteed by U.S. government agencies or instrumentalities are not backed by the full faith and credit of the U.S. and may only be supported by the right of the agency or instrumentality to borrow from the U.S. Treasury. There can be no assurance that the U.S. government will always provide financial support to those agencies or instrumentalities.

Lower-Rated Debt Securities Risk. Below investment grade securities (commonly called junk bonds) are regarded as having predominately speculative characteristics with respect to the issuer’s continuing ability to pay principal and interest and carry a greater risk that the issuer of such securities will default in the timely payment of principal and interest. Issuers of securities that are in default or have defaulted may fail to resume principal or interest payments, in which case the Fund may lose its entire investment.

Restricted Securities Risk. Restricted securities may not be listed on an exchange and may not have an active trading market. Accordingly, the prices of these securities may be more difficult to determine than publicly traded securities and these securities may involve heightened risk as compared to investments in securities of publicly traded companies. In addition, restricted securities may be illiquid, and it can be difficult to sell them at a time when it may otherwise be desirable to do so or the Fund may be able to sell them only at prices that are less than what the Fund regards as their fair market value. Transaction costs may be higher for these securities. In addition, the Fund may get only limited information about the issuer of a restricted security.

Prepayment and Extension Risk. If borrowers pay back principal on certain fixed-income securities, such as mortgage- or asset-backed securities, before (prepayment) or after (extension) the market anticipates such payments, shortening or lengthening their duration, the Fund’s performance could be impacted. In general, a debt security might be called or otherwise converted, prepaid or redeemed before maturity due to an excess in cash flow to the issuer or due to a decline in interest rates. In the event there is a prepayment, the Fund

would need to reinvest the proceeds, possibly in an investment offering a lower yield or interest rate. On the other hand, in general, slower payoffs or extension may occur if market interest rates rise, which has the effect of increasing the duration or interest rate risk of the impacted securities.

Market Risk. The Fund is subject to market risk—the risk that securities markets and individual securities will increase or decrease in value. Market risk applies to every market and every security. Security prices may fluctuate widely over short or extended periods in response to adverse issuer, political, geopolitical (including wars or acts of terrorism), regulatory, market, economic, sanctions, tariffs, global health crises or pandemics, environmental, or other developments that may cause broad changes in market value, stability, and public perceptions concerning these developments, and adverse investor sentiment. In addition, securities markets tend to move in cycles. If there is a general decline in the securities markets, it is possible your investment may lose value regardless of the individual results of the companies in which the Fund invests. The magnitude of up and down price or market fluctuations over time is sometimes referred to as “volatility,” which, at times, can be significant. In addition, different asset classes and geographic markets may experience periods of significant correlation with each other. As a result of this correlation, the securities and markets in which the Fund invests may experience volatility due to market, economic, political or social events, such as global health crises or pandemics, and conditions that may not readily appear to directly relate to such securities, the securities’ issuer or the markets in which they trade. In addition, some companies may have substantial foreign operations or holdings and may involve additional risks relating to those markets, including but not limited to political, economic, regulatory, or other conditions in foreign countries, as well as currency exchange rates.

Derivatives Risk. The Fund’s exposure to derivatives can involve investment techniques and risks different from those associated with investing in more traditional investments and sometimes the risks of these investments may be magnified in comparison. Derivative transactions may be volatile and can create leverage in the Fund, which may cause the Fund to lose more than the amount of assets initially invested. At times, derivatives may be highly illiquid, and the Fund may not be able to close out or sell a derivative at the desired time or price. If the Fund’s derivative counterparty becomes unwilling or unable to honor its obligations, then the Fund may experience losses. This risk is greater for forward currency contracts, swaps and other over-the-counter traded derivatives. Changes in regulation relating to a mutual fund’s use of derivatives and related instruments may limit the availability of derivatives, increase the costs of derivatives, or otherwise adversely affect the value of derivatives impacting the Fund’s performance.

Additional risks associated with certain types of derivatives are discussed below:

Forward Contracts. Forward contracts do not have limitations on daily price movements. Changes in foreign exchange regulations by governmental authorities may affect the trading of forward contracts on currencies.

Futures. Futures contracts are subject to the risk that an exchange may impose price fluctuation limits, which may make it difficult or impossible for a fund to exit a position when desired.

Options. The use of options involves investment strategies and risks different from those associated with ordinary portfolio securities transactions. If a strategy is applied at an inappropriate time or market conditions or trends are judged incorrectly, the use of options may lower the Fund’s return. There can be no guarantee that the use of options will increase the Fund’s return or income. In addition, there may be an imperfect correlation between the movement in prices of options and the securities underlying them and there may at times not be a liquid secondary market for various options.

Swaps. Generally, the risk of loss associated with swaps is limited to the net amount of payments that the Fund is contractually obligated to make or, in the case of the counterparty defaulting, the net amount of payments that the Fund is contractually entitled to receive. However, if the Fund sells a credit default swap it may lose the entire notional amount of the swap.

Variable and Floating Rate Instruments Risk. The value of variable and floating rate instruments may decline if market interest rates or the interest rates paid by such instruments do not fluctuate according to expectations since such instruments are less sensitive to interest rate changes than fixed rate instruments. Certain types of variable and floating rate instruments, such as interests in bank loans, may be subject to greater liquidity risk than other debt securities.

Common Stock Risk. Common stocks are generally subject to greater fluctuations in market value than other asset classes as a result of such factors as a company’s business performance, investor perceptions, stock market trends and general economic conditions. The rights of common stockholders are subordinate to all other claims on a company’s assets including, debt holders and preferred stockholders; therefore, the Fund could lose money if a company in which it invests becomes financially distressed.

Value Style Risk. Investing in “value” stocks presents the risk that the stocks may never reach what the Adviser believes are their full market values, either because the market fails to recognize what the Adviser considers to be the companies’ intrinsic values or because the Adviser misjudged those values. In addition, value stocks may fall out of favor with investors and underperform other investments during given periods.

High Portfolio Turnover Risk. The Fund may engage in active and frequent trading and may have a high portfolio turnover rate, which may increase the Fund’s costs, negatively impact the Fund’s performance and may generate a greater amount of capital gain distributions to shareholders than if the Fund had a low portfolio turnover rate.