J.P. MORGAN U.S. EQUITY FUNDS

JPMorgan Diversified Fund

(the “Fund”)

(a series of JPMorgan Trust I)

(All Share Classes)

Supplement dated May 13, 2020

to the Summary Prospectuses and Prospectuses dated November 1, 2019, as supplemented

Effective June 15, 2020, the following changes will be made to each Summary Prospectus and Prospectus of the Fund:

The “What are the Fund’s main investment strategies?” section of each Summary Prospectus and Prospectus of the Fund shall be deleted and replaced with the following:

Drawing on a variety of analytical tools, the Fund’s adviser typically seeks to invest the Fund’s assets among various types of asset classes based on the following allocations:

• 35%–80% equity securities

• 15%–65% fixed income securities

• 0%–10% convertible securities

The Fund invests in separate underlying strategies by investing directly in individual securities and/or in other J.P. Morgan Funds, across asset classes, including: U.S. equity and developed international equity across market capitalizations, emerging markets equity, domestic and foreign fixed income, high yield fixed income, emerging markets debt, and real estate investment trusts (REITs).

The adviser may periodically increase or decrease the Fund’s actual asset allocations according to the relative attractiveness of each asset class.

Within its equity allocations, the Fund primarily invests in the common stock of U.S. and foreign companies, REITs and J.P. Morgan equity funds. In this context, a J.P. Morgan fund will be considered an equity fund if its prospectus discloses that the fund invests primarily in equity securities, including REITs.

Within its fixed income allocations, the Fund primarily invests in corporate bonds, asset-backed, mortgage-related, and mortgage-backed securities, U.S. and foreign government securities, loan assignments and participations (Loans) and commitments to purchase loan assignments, emerging market debt and J.P. Morgan fixed income funds. In this context, a J.P. Morgan fund will be considered a fixed income fund if its prospectus discloses that the fund invests primarily in fixed income securities.

The Fund may invest in fixed income securities of any credit quality but may only invest up to 25% of its total assets in certain below investment grade securities (also known as high yield securities or junk bonds). This limit on below investment grade securities will include all investments held either directly by the Fund or in J.P. Morgan funds held by the Fund which invest primarily in below investment grade securities (as disclosed in the underlying fund’s prospectus). In addition, the Fund may invest in J.P. Morgan fixed income funds that may invest in fixed income securities of various credit qualities, including at times below investment grade securities, in order to expose the Fund to certain asset classes, such as emerging market debt. The remainder of the fixed income allocation will be invested directly in securities that, at the time of purchase are rated investment grade by a nationally recognized statistical rating organization or in securities that are unrated but are deemed by the Fund’s adviser to be of comparable quality. The Fund may invest in fixed income securities of any average weighted maturity or duration.

The Fund may invest up to 30% of its total assets in shares of other J.P. Morgan equity or fixed income funds (collectively, J.P. Morgan Funds) in order to expose the Fund to certain asset classes. These include both mutual funds and exchange-traded funds (ETFs) managed by the adviser or its affiliates. As a main investment strategy, the adviser expects to select only J.P. Morgan Funds without considering or canvassing the universe of unaffiliated underlying funds available even though there may (or may not) be one or more unaffiliated underlying funds that investors might regard are more attractive for the Fund or that have superior returns.

The Fund may also invest up to 10% of its assets in convertible securities.

In addition to direct investments in securities, derivatives, which are instruments that have a value based on another instrument, exchange rate or index, may be used as substitutes for securities in which the Fund can

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invest. With respect to its fixed income allocations, the Fund may use futures contracts to manage and hedge interest rate risk associated with these investments, as well as to lengthen or shorten the duration of this portion of the portfolio. With respect to its equity and fixed income allocations, the Fund may use futures contracts to gain or reduce exposure to all or a portion of the stock or fixed income markets, respectively and for cash management. The Fund may use forward foreign currency exchange contracts to hedge or manage its foreign currency risk, as well as to gain exposure to certain currencies.

Although the Fund will generally maintain its assets within the allocations above, the Fund may hold cash or cash equivalents for various purposes, including in connection with segregation for derivatives transactions, as collateral for derivatives transactions or for temporary defensive purposes.

The adviser establishes the strategic and tactical allocation for the Fund and makes the day-to-day decisions concerning strategies and overall construction of the Fund. As attractive investments arise across asset classes and strategies, the adviser attempts to capture these opportunities by allocating the Fund’s assets among strategies and asset classes within pre-defined ranges.

Investment decisions within strategies and asset classes are implemented either by the portfolio managers of the Fund’s underlying strategies who select individual securities for the Fund or with the Fund’s purchase of other J.P. Morgan Funds.

The frequency with which the Fund buys and sells underlying investments will vary from year to year, depending on, but not limited to: market conditions, performance of the underlying investments, and changes in the adviser’s investment views.

Corresponding changes will also be made to the “More About the Funds — Additional Information About the Funds’ Investment Strategies — Diversified Fund” section in each Prospectus of the Fund.

The “The Fund’s Main Investment Risks — Derivative Risk” section in each Summary Prospectus and Prospectus of the Fund shall be deleted in its entirety and replaced with the following:

Derivatives Risk. Derivatives, including futures and foreign currency exchange contracts, may be riskier than other types of investments and may increase the volatility of the Fund. Derivatives may be sensitive to changes in economic and market conditions and may create leverage, which could result in losses that significantly exceed the Fund’s original investment. The Fund may be more volatile than if the Fund had not been leveraged because the leverage tends to exaggerate any effect on the value of the Fund’s portfolio securities. Certain derivatives expose the Fund to counterparty risk, which is the risk that the derivative counterparty will not fulfill its contractual obligations (and includes credit risk associated with the counterparty). Certain derivatives are synthetic instruments that attempt to replicate the performance of certain reference assets. With regard to such derivatives, the Fund does not have a claim on the reference assets and is subject to enhanced counterparty risk. Derivatives may not perform as expected, so the Fund may not realize the intended benefits. When used for hedging, the change in value of a derivative may not correlate as expected with the security or other risk being hedged. In addition, given their complexity, derivatives expose the Fund to risks of mispricing or improper valuation.

The second sentence of the first paragraph of the “More About the Funds — Additional Information About the Funds’ Investment Strategies — Each of the Funds” section in each Prospectus of the Fund shall be deleted in its entirety and replaced with the following:

The Diversified Fund will invest at least 35% of its assets in equity securities.

INVESTORS SHOULD RETAIN THIS SUPPLEMENT WITH THE

SUMMARY PROSPECTUSES AND PROSPECTUSES FOR FUTURE REFERENCE