X0607 3 2026-09-01 0 0000310158 Merck & Co., Inc. MRK 0002148939 Gupta Gaurav K false 126 EAST LINCOLN AVENUE RAHWAY NJ 07065 1 EVP, CIDO Common Stock 750 D Restricted Stock Unit 2027-08-07 2029-08-07 Common Stock 19443 D These restricted stock units vest and are distributed as shares of Merck & Co., Inc. common stock in three equal installments on 8/7/2027, 8/7/2028, and 8/7/2029. Each restricted stock unit represents a contingent right to receive one share of Merck & Co., Inc. common stock. See Exhibit 24 - Power of Attorney /s/ Kelly E. Grez, as Attorney-in-Fact for Gaurav Gupta 2026-09-01