X0306 4 2019-02-04 0000310158 Merck & Co., Inc. MRK 0001140799 GLOCER THOMAS H MERCK & CO., INC. 2000 GALLOPING HILL ROAD KENILWORTH NJ 07033 1 Common Stock 2019-02-04 4 M 0 5000.0000 35.1900 A 10100.0000 D Common Stock 2019-02-04 4 M 0 5000.0000 24.3000 A 15100.0000 D Common Stock 2019-02-04 4 S 0 10000.0000 75.9590 D 5100.0000 D Stock Option (right to buy) 24.3000 2019-02-04 4 M 0 5000.0000 0.0000 D 2010-05-01 2019-04-30 Common Stock 5000.0000 0.0000 D Stock Option (right to buy) 35.1900 2019-02-04 4 M 0 5000.0000 0.0000 D 2011-08-04 2020-08-03 Common Stock 5000.0000 0.0000 D The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $75.9500 to $75.9800, 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. The option became exercisable in equal installments on 5/1/2010, 5/1/2011 and 5/1/2012. The option became exercisable in equal installments on 8/4/2011, 8/4/2012 and 8/4/2013. Faye C. Brown as Attorney-in-Fact for Thomas H. Glocer 2019-02-04