Sec Form 4 Filing - Allen Andrew R @ Gritstone bio, Inc. - 2022-01-31

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Allen Andrew R 2. Issuer Name and Ticker or Trading Symbol Gritstone bio, Inc. [ GRTS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President and CEO (Last) (First) (Middle) C/O GRITSTONE BIO, INC., 5959 HORTON STREET, SUITE 300 3. Date of Earliest Transaction (MM/DD/YY) 01/31/2022 (Street) EMERYVILLE, CA94608 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 01/31/2022 A 70,000( 1 ) A $ 0 118,200( 2 ) D Common Stock 1,449,275 I See footnote( 3 )

01/31/2022 Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (Right to Buy) $ 5.46 A 410,000 ( 4 ) 01/30/2032 Common Stock 410,000 $ 0 410,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Allen Andrew R C/O GRITSTONE BIO, INC. 5959 HORTON STREET, SUITE 300 EMERYVILLE, CA94608 X President and CEO Signatures /s/ Rahsaan Thompson, Attorney-in-Fact for Andrew R. Allen 04/20/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )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. ( 2 )Includes 94,100 Restricted Stock Units which are subject to vesting. ( 3 )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. ( 4 )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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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