Form: 4

Statement of changes in beneficial ownership of securities

December 16, 2025

Documents

SEC Form 4
FORM 4 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
or Section 30(h) of the Investment Company Act of 1940
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 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
  
 Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Chung Jane
(Last) (First) (Middle)
C/O SUTRO BIOPHARMA, INC.
111 OYSTER POINT BLVD.
(Street)
SOUTH SAN FRANCISCO CA 94080
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
SUTRO BIOPHARMA, INC. [ STRO ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
X Director 10% Owner
X Officer (give title below) Other (specify below)
Chief Executive Officer
3. Date of Earliest Transaction (Month/Day/Year)
12/12/2025
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 12/12/2025 M 2,500 A $0 14,785 D
Common Stock 12/12/2025 F 894(1) D $8.015 13,891 D
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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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 (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (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: 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
Restricted Stock Unit (RSU) (2) 12/12/2025 M 2,500 (3) 12/01/2027 Common Stock 2,500 $0 5,000 D
Explanation of Responses:
1. Represents the number of shares of Common Stock that have been withheld by the Issuer to satisfy its income tax withholding and remittance obligations in connection with the net settlement of RSUs; does not represent a sale by the reporting person.
2. Each RSU represents a contingent right to receive one share of the Issuer's Common Stock upon settlement.
3. The RSU award vested or vests as to 1/4th of the total award annually, subject to continued service through each vesting date, with the first tranche vested on December 1, 2024. The reported transaction represents the deferred vesting and settlement of a tranche of this award pursuant to the terms of the reporting person's award agreement with the Issuer.
Remarks:
Effective as of 12:01 a.m. Eastern time on December 3, 2025, pursuant to a Certificate of Amendment to the Issuer's Restated Certificate of Incorporation previously approved by the Issuer's stockholders, and filed with the Delaware Secretary of State on December 2, 2025, the Issuer's Common Stock, par value $0.001 per share, underwent a 1-for-10 reverse stock split (the "Reverse Stock Split"). All amounts, including all dollar values, set forth herein have been adjusted to reflect the Reverse Stock Split.
/s/ David Pauling as attorney-in-fact for Jane Chung 12/16/2025
** Signature of Reporting Person 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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.