X0508 4 2026-02-28 0000062709 MARSH & MCLENNAN COMPANIES, INC. MRSH 0001726937 Mills Stacy 1166 AVENUE OF THE AMERICAS NEW YORK 1 Vice President and Controller 0 Common Stock 2026-02-28 4 M 0 2723 0 A 5428.098 D Common Stock 2026-02-28 4 F 0 1277 186.74 D 4151.098 D Restricted Stock Units 2026-02-28 4 M 0 2723 0 D Common Stock 2723 2916 D Vesting and distribution to reporting person of 2,723 shares underlying restricted stock units of which 1,277 were withheld by Marsh & McLennan Companies to cover applicable taxes. These 2,723 shares underlying restricted stock units relate to 508 restricted stock units that were granted on February 23, 2023, 457 restricted stock units that were granted on February 22, 2024, 416 restricted stock units that were granted on February 18, 2025 and 1,342 restricted stock units relating to performance stock units that were granted on February 23, 2023 for the performance period 2023-2025. The security converts to Marsh & McLennan Companies common stock on a 1-for-1 basis. Not applicable. /s/ Tessa Patti, Attorney-in-fact 2026-03-03