X0306 4 2022-01-31 0 0001656634 Gritstone bio, Inc. GRTS 0001374539 Allen Andrew R C/O GRITSTONE BIO, INC. 5959 HORTON STREET, SUITE 300 EMERYVILLE CA 94608 1 1 0 0 President and CEO Common Stock 2022-01-31 4 A 0 70000 0 A 118200 D Common Stock 1449275 I See footnote Stock Option (Right to Buy) 5.46 2022-01-31 4 A 0 410000 0 A 2032-01-30 Common Stock 410000 410000 D Represents Restricted Stock Units ("RSUs") which vest on the first anniversary of the grant date. Each RSU represents a contingent right to receive one share of common stock of the Issuer. Includes 94,100 Restricted Stock Units which are subject to vesting. The shares are held in the name of the Reporting Person's revocable trust of which the Reporting Person is a co-trustee. The Reporting person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein. One forty-eighth (1/48th) of the shares initially subject to the option will vest on each monthly anniversary measured from January 31, 2022 (the "Vesting Commencement Date"), so that 100% of the shares subject to the option will be fully vested and exercisable as of the fourth anniversary of the Vesting Commencement Date, subject to the Reporting Person's continued service through each vesting date. /s/ Rahsaan Thompson, Attorney-in-Fact for Andrew R. Allen 2022-04-20