Prospectus Supplement

July 2, 2025

Morgan Stanley Institutional Fund, Inc.

Supplement dated July 2, 2025, to the Morgan Stanley Institutional Fund, Inc. Prospectuses dated April 30, 2025, as supplemented

Advantage Portfolio
American Resilience Portfolio
Asia Opportunity Portfolio
Developing Opportunity Portfolio
Emerging Markets ex China Portfolio
Emerging Markets Leaders Portfolio
Emerging Markets Portfolio
Global Concentrated Portfolio
Global Core Portfolio
Global Endurance Portfolio
Global Franchise Portfolio
Global Insight Portfolio
Global Opportunity Portfolio
Global Permanence Portfolio
Global Stars Portfolio
Growth Portfolio
Inception Portfolio
International Advantage Portfolio
International Equity Portfolio
International Opportunity Portfolio
International Resilience Portfolio
Multi-Asset Real Return Portfolio
Next Gen Emerging Markets Portfolio
Passport Overseas Equity Portfolio
Permanence Portfolio
US Core Portfolio
Vitality Portfolio

Effective immediately, the section of each Prospectus titled "Appendix A—Intermediary-Specific Sales Charge Waivers and Discounts—Wells Fargo Advisors Financial Network, LLC (collectively, "Wells Fargo Advisors")" is hereby deleted in its entirety and replaced with the following:

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Wells Fargo Advisors Financial Network, LLC (collectively, "Wells Fargo Advisors")

Wells Fargo Clearing Services, LLC operates a First Clearing business, but these rules are not intended to include First Clearing firms.

Effective October 1, 2025, Clients of Wells Fargo Advisors purchasing fund shares through Wells Fargo Advisors are eligible for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in the prospectus or statement of additional information ("SAI"). In all instances, it is the investor's responsibility to inform Wells Fargo Advisors at the time of purchase of any relationship, holdings, or other facts qualifying the investor for discounts or waivers. Wells Fargo Advisors can ask for documentation supporting the qualification.

Wells Fargo Advisors Class A share front-end sales charge waivers information.

Wells Fargo Advisors clients purchasing or converting to Class A shares of the fund in a Wells Fargo Advisors brokerage account are entitled to a waiver of the front-end load in the following circumstances:

•  Wells Fargo Advisors employee and employee-related accounts according to Wells Fargo Advisor's employee account linking rules. Legacy accounts and positions receiving affiliate discounts prior to the effective date will continue to receive discounts. Going forward employees of affiliate businesses will not be offered NAV.

•  Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

WellsTrade, the firm's online self-directed brokerage account, generally offers no-load share classes but there could be instances where a Class A share is offered without a front-end sales charge.

Wells Fargo Advisors Class 529-A share front-end sales charge waivers information.

Wells Fargo Advisors clients purchasing or converting to Class 529-A shares of the fund through Wells Fargo Advisors transactional brokerage accounts are entitled to a waiver of the front-end load in the following circumstances:

•  Shares purchased through a rollover from another 529 plan.

•  Recontribution(s) of distributed funds are only allowed during the NAV reinstatement period as dictated by the sponsor's specifications outlined by the plan.

Wells Fargo Advisors is not able to apply the NAV Reinstatement privilege for 529 Plan account purchases placed directly at the fund company. Investors wishing to utilize this privilege outside of Wells Fargo systems will need to do so directly with the Plan or a financial intermediary that supports this feature.

Unless specifically described above, other front-end load waivers are not available on mutual fund purchases through Wells Fargo Advisors.

Wells Fargo Advisors Contingent Deferred Sales Charge information.

•  Contingent deferred sales charges (CDSC) imposed on fund redemptions will not be rebated based on future purchases.

Wells Fargo Advisors Class A front-end load discounts

Wells Fargo Advisors Clients purchasing Class A shares of the fund through Wells Fargo Advisors brokerage accounts will follow the following aggregation rules for breakpoint discounts:

•  As of the effective date, SEP or SIMPLE IRAs will not be aggregated as a group plan. They will aggregate with the client's personal accounts based on Social Security Number. Previously established SEP and SIMPLE IRAs may still be aggregated as a group plan.

•  Effective October 1, 2025, Employer-sponsored retirement plan (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans) accounts will aggregate with other plan accounts under the same Tax ID and will not be aggregated with other retirement plan accounts under a different Tax ID or personal accounts. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, SIMPLE IRAs, SAR-SEPs or Keogh plans.

•  Gift of shares will not be considered when determining breakpoint discounts.

Please retain this supplement for future reference.

  IFIWFPROSPT 7/25