Executive Change

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C.  20549 _____________________ FORM 8-K   CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934   Date of report (Date of earliest event reported) February 25, 2026 Marsh & McLennan Companies, Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 1-5998 36-2668272 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS Employer Identification No.) 1166 Avenue of the Americas, New York, NY 10036 (Address of Principal Executive Offices) (Zip Code) Registrant’s telephone number, including area code (212) 345-5000     Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:   ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)   ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)   ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))   ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))     Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading symbol(s) Name of exchange on which registered Common Stock, par value $1.00 per share MRSH New York Stock Exchange NYSE Texas     Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.   ☐ Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers (d) On February 25, 2026, the board of directors (the “Board”) of Marsh & McLennan Companies, Inc. (the “Company”) appointed Peter Harrison, age 59, as an independent member of the Board, effective immediately. Mr. Harrison’s Board committee assignments have not yet been determined. The Company expects to disclose such assignments in its definitive proxy statement for its 2026 Annual Meeting of Stockholders. As a non-management director, Mr. Harrison will be compensated as described in “Description of Compensation Arrangements for Independent Directors”, which was filed as Exhibit 10.2 to the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2025. A copy of the Company's press release, dated February 25, 2026, announcing the appointment of Mr. Harrison is attached hereto as Exhibit 99.1 and incorporated herein by reference. Item 9.01        Financial Statements and Exhibits   (d)        Exhibits   99.1        Press release issued by Marsh & McLennan Companies, Inc. on February 25, 2026 2 SIGNATURES     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.   MARSH & McLENNAN COMPANIES, INC.         By: /s/ Connor Kuratek      Name: Connor Kuratek   Title: Deputy General Counsel and Corporate Secretary     Date:    February 25, 2026 3