Sec Form 4 Filing - Srinivasan Venkatesh @ SUTRO BIOPHARMA, INC. - 2023-05-01

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 Srinivasan Venkatesh 2. Issuer Name and Ticker or Trading Symbol SUTRO BIOPHARMA, INC. [ STRO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Tech Op Officer (Last) (First) (Middle) C/O SUTRO BIOPHARMA, INC., 111 OYSTER POINT BLVD. 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2023 (Street) SOUTH SAN FRANCISCO, CA94080 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

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 Common Stock) $ 4.58 05/01/2023 A 7,500 ( 1 ) 05/01/2033 Common Stock 7,500 $ 0 7,500 D Restricted Stock Unit (RSU) ( 2 ) 05/01/2023 A 10,000 ( 3 ) 05/01/2027 Common 10,000 $ 0 10,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Srinivasan Venkatesh C/O SUTRO BIOPHARMA, INC. 111 OYSTER POINT BLVD. SOUTH SAN FRANCISCO, CA94080 Chief Tech Op Officer Signatures /s/ Edward C. Albini as attorney-in-fact for Venkatesh Srinivasan 05/02/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The option vests as to 2.0833% of the total shares monthly, beginning on June 1, 2023, with 100% of the total shares vested and exercisable on May 1, 2027, subject to the reporting person's provision of service to the issuer on each vesting date. ( 2 )Each RSU represents a contingent right to receive one (1) share of the issuer's Common Stock upon settlement. ( 3 )The RSUs vest as to 1/4th of the total shares annually beginning on May 1, 2024, subject to 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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