X0306 4 2021-11-01 0000310158 Merck & Co., Inc. MRK 0001628884 Gerberding Julie L. MERCK & CO., INC. 2000 GALLOPING HILL ROAD KENILWORTH NJ 07033 1 EVP, Chief Patient Officer Common Stock 2021-11-01 4 M 0 35287 0 A 74449.138 D Common Stock 2021-11-01 4 M 0 30175 0 A 104624.138 D Common Stock 2021-11-01 4 M 0 19394 0 A 124018.138 D Common Stock 2021-11-01 4 M 0 11414 0 A 135432.138 D Common Stock 2021-11-01 4 S 0 96270 87.9057 D 39162.138 D Stock Option (Right to Buy) 62.07 2021-11-01 4 M 0 35287 0 D 2018-05-05 2027-05-04 Common Stock 35287 0 D Stock Option (Right to Buy) 56.04 2021-11-01 4 M 0 30175 0 D 2019-05-04 2028-05-03 Common Stock 30175 0 D Stock Option (Right to Buy) 77.62 2021-11-01 4 M 0 19394 0 D 2020-05-03 2029-05-02 Common Stock 19394 9698 D Stock Option (Right to Buy) 75.36 2021-11-01 4 M 0 11414 0 D 2021-05-01 2030-04-30 Common Stock 11414 22831 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $87.9050 to $87.9250, inclusive. The reporting person undertakes to provide to Merck & Co., Inc., any security holder of Merck & Co., Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above in this footnote. Holdings include shares acquired in dividend reinvestment transactions. Exercise price and holdings reflect the adjustments that occurred as of June 2, 2021 in connection with the Organon & Co. ("Organon") spin-off as described in the registration statement on Form 10 filed with the SEC by Organon (the "Form 10"). As reported in the Form 10, all Merck stock option awards outstanding as of immediately prior to the distribution date were converted on the distribution date into adjusted Merck awards for Merck employees to preserve the same intrinsic value and general terms and conditions (including vesting) as were in place immediately prior to the adjustments. The option became exercisable in equal installments on 5/5/2018, 5/5/2019 and 5/5/2020. The option became exercisable in equal installments on 5/4/2019, 5/4/2020, and 5/4/2021. The option vests and becomes exercisable in three equal installments on 5/3/2020, 5/3/2021 and 5/3/2022. The option vests and becomes exercisable in three equal installments on 5/1/2021, 5/1/2022 and 5/1/2023. /s/ Kelly E. W. Grez as Attorney-in-Fact for Julie L. Gerberding 2021-11-03