X0306 4 2023-01-23 0000310158 Merck & Co., Inc. MRK 0001421339 DeLuca Richard R. MERCK & CO., INC. 126 EAST LINCOLN AVENUE RAHWAY NJ 07065 1 EVP&Pres, Merck Animal Heallth Common Stock 2023-01-23 4 A 0 15628 109.88 A 153500.379 D Common Stock - 401(k) Plan 1198.0497 I By 401(k) Distribution of net after tax shares of common stock on satisfaction of performance criteria for performance share units granted on 3/31/20. Performance shares were paid out at 110 percent of target awards. Includes dividends accrued over the three-year performance period ending December 31, 2022. Holdings include shares acquired in dividend reinvestment transactions. Includes shares acquired and dividends earned through January 9, 2023 in the Merck U.S. Savings Plan, a 401(k) plan. /s/ Kelly E. W. Grez as Attorney-in-Fact for Richard R. DeLuca, Jr. 2023-01-25