MARSH & MCLENNAN COMPANIES INC

Rule 10b5-1 Trading Plans

The following Section 16 officers (as defined in Rule 16a-1(f) under the Exchange Act) adopted "Rule 10b5-1 trading arrangements," as defined in Regulation S-K, Item 408, intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act:

•John Doyle, our Chief Executive Officer, adopted a trading plan on December 2, 2024, which provides for the exercise and sale of an aggregate of 84,318 options. The plan will terminate on December 2, 2025, subject to early termination for certain specified events set forth in the plan.

•Paul Beswick, our Senior Vice President and Chief Information Officer, adopted a new trading plan on December 6, 2024, which provides for the (1) sale of 2,120 shares, (2) sale up to 7,928 shares subject to performance stock units ("PSUs") and (3) exercise and sale of 5,000 stock options, in each case excluding any shares withheld by the company to satisfy its income tax withholding obligations in connection with the net settlement of equity awards. The plan’s maximum length is until December 5, 2025, subject to early termination for certain specified events set forth in the plan.

•Dean Klisura, our President and Chief Executive Officer of Guy Carpenter and Vice Chair, Marsh McLennan, adopted a new trading plan on December 6, 2024, which provides for the (1) sale of up to 9,910 shares subject to PSUs, (2) sale of up to 6,024 shares subject to restricted stock units ("RSUs") and (3) exercise and sale of 9,569 stock options, in each case excluding any shares withheld by the company to satisfy its income tax withholding obligations in connection with the net settlement of equity awards. The plan’s maximum length is until December 5, 2025, subject to early termination for certain specified events set forth in the plan.

•Mark McGivney, our Chief Financial Officer, adopted a new trading plan on December 6, 2024, which provides for the (1) sale of up to 21,472 shares subject to PSUs and (2) exercise and sale of 67,421 stock options, in each case excluding any shares withheld by the company to satisfy its income tax withholding obligations in connection with the net settlement of equity awards. The plan’s maximum length is until December 5, 2025, subject to early termination for certain specified events set forth in the plan.

•Stacy Mills, our Vice President and Controller, adopted a new trading plan on December 6, 2024, which provides for the (1) sale of up to 1,488 shares subject to PSUs, (2) sale of 1,461 shares subject to RSUs and (3) exercise and sale of 4,207 stock options, in each case excluding any shares withheld by the company to satisfy its income tax withholding obligations in connection with the net settlement of equity awards. The plan’s maximum length is until December 5, 2025, subject to early termination for certain specified events set forth in the plan.

The actual number of shares subject to PSUs that may be sold pursuant to each plan described above is subject to satisfaction of the applicable performance conditions and may vary from the number above.

PART III