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, modified orterminated "Rule 10b5-1 trading arrangements" (as defined in Item 408 under Regulation S-K of the Exchange Act):

•Paul Beswick, our Senior Vice President and Chief Information Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Beswick to (1) sell 1,450 shares, (2) sell up to 8,510 shares subject to performance stock units (" PSUs") and (3) exercise and sell 5,000 stock options.

•Dean Klisura, our President and Chief Executive Officer of Guy Carpenter and Vice Chair, Marsh McLennan, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Klisura to (1) sell up to 4,256 shares subject to PSUs, (2) sell 1,419 shares subject to restricted stock units ("RSUs") and (3) exercise and sell 9,994 stock options.

•Mark McGivney, our Chief Financial Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. McGivney to (1) sell up to 25,526 shares subject to PSUs and (2) exercise and sell 66,393 stock options.

•Stacy Mills, our Vice President and Controller, adopted a new trading plan on December 13, 2023. The plan’s maximum length is until December 12, 2024, and first trades will not occur until March 13, 2024, at the earliest. The trading plan is intended to permit Ms. Mills to (1) sell up to 1,702 shares subject to PSUs, (2) sell 1,572 shares subject to RSUs and (3) exercise and sell 4,101 stock options.

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