X0306 4/A 2018-01-12 2018-01-16 0000310158 Merck & Co., Inc. MRK 0001168014 GRADDICK WEIR MIRIAN M MERCK & CO., INC. 2000 GALLOPING HILL ROAD KENILWORTH NJ 07033 1 Exe V-P, HR Common Stock 2018-01-12 4 S 0 8000.0000 58.0000 D 98484.3190 D Common Stock 2018-01-16 4 M 0 52000.0000 44.3000 A 150484.3190 D Common Stock 2018-01-16 4 S 0 8000.0000 61.6300 D 142484.3190 D Common Stock 2018-01-16 4 S 0 52000.0000 61.6300 D 90484.3190 D The sale reported in this Form 4 is made pursuant to a Rule 10b5-1 trading plan. The original Form 4, filed on January 16, 2018, is being amended by this Form 4 amendment solely to correct an administrative error, which misreported a sale that occurred on January 12, 2018 as a total of 5,000 shares sold when in fact 8,000 shares of the Issuer's common stock were sold. As a result of this administrative error, the number of shares beneficially owned by the reporting person following the corrected transaction reflects a reduction in the number of shares reported as beneficially owned by the reporting person by 3,000 shares, and includes shares acquired in dividend reinvestment transactions. The exercise and sale transactions reported in this Form 4 are made pursuant to a Rule 10b5-1 trading plan. Faye C. Brown as Attorney-in-Fact for Mirian M. Graddick-Weir 2018-01-19