X0508 4 2025-02-28 0000062709 MARSH & MCLENNAN COMPANIES, INC. MMC 0002016426 Tomlinson Patrick 1166 AVENUE OF THE AMERICAS NEW YORK NY 10036 1 President and CEO, Mercer 0 Common Stock 2025-02-28 4 M 0 2812 0 A 3412 D Common Stock 2025-02-28 4 F 0 1437 233.74 D 1975 D Restricted Stock Units 2025-02-28 4 M 0 2812 0 D Common Stock 2812 7919 D Vesting and distribution to reporting person of 2,812 shares underlying restricted stock units of which 1,437 were withheld by Marsh & McLennan Companies to cover applicable taxes. These 2,812 shares underlying restricted stock units relate to 551 restricted stock units that were granted on February 23, 2022, 609 restricted stock units that were granted on February 23, 2023 and 1,652 restricted stock units relating to performance stock units that were granted on February 23, 2022 for the performance period 2022-2024. The security converts to Marsh & McLennan Companies common stock on a 1-for-1 basis. Not Applicable. /s/ Tessa Patti, Attorney-in-fact 2025-03-04