X0306 4 2017-09-01 0000882095 GILEAD SCIENCES INC GILD 0001334682 Alton Gregg H GILEAD SCIENCES, INC. 333 LAKESIDE DRIVE FOSTER CITY CA 94404 1 EVP Comm&Acs ALA, Corp&Med Aff Common Stock 2017-09-01 4 M 0 17250 24.905 A 101488 D Common Stock 2017-09-01 4 S 0 21263 82.9601 D 80225 D Common Stock 2017-09-01 4 S 0 3737 83.5449 D 76488 D Non-qualified Stock Option (Right to Buy) 24.905 2017-09-01 4 M 0 17250 0 D 2019-07-29 Common Stock 17250 50626 D The exercise and sale transactions reported in this Form 4 are made pursuant to a Rule 10b5-1 trading plan. The options have a five year vesting schedule. 20% vest on the first anniversary of the date of grant. The balance will vest 5% quarterly thereafter until fully vested. Sale prices reported for the transactions reported here range from $82.31 to $83.31. Full information regarding the number of shares purchased or sold at each separate price will be provided to the SEC, the issuer or its shareowners upon request. Sale prices reported for the transactions reported here range from $83.32 to $84.05. Full information regarding the number of shares purchased or sold at each separate price will be provided to the SEC, the issuer or its shareowners upon request. /s/ Marissa Song by Power of Attorney for Gregg H. Alton 2017-09-06