Jane Chung - 12 Dec 2025 Form 4 Insider Report for SUTRO BIOPHARMA, INC. (STRO)

Role
Chief Executive Officer, Director
Signature
/s/ David Pauling as attorney-in-fact for Jane Chung
Issuer symbol
STRO
Transactions as of
12 Dec 2025
Net transactions value
-$7,165
Form type
4
Filing time
16 Dec 2025, 20:47:26 UTC
Previous filing
16 Oct 2025
Next filing
03 Mar 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Chung Jane Chief Executive Officer, Director C/O SUTRO BIOPHARMA, INC., 111 OYSTER POINT BLVD., SOUTH SAN FRANCISCO /s/ David Pauling as attorney-in-fact for Jane Chung 16 Dec 2025 0001872398

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction STRO Common Stock Options Exercise $0 +2,500 +20% $0.000000 14,785 12 Dec 2025 Direct
transaction STRO Common Stock Tax liability $7,165 -894 -6% $8.02 13,891 12 Dec 2025 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction STRO Restricted Stock Unit (RSU) Options Exercise $0 -2,500 -33% $0.000000 5,000 12 Dec 2025 Common Stock 2,500 Direct F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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.
F2 Each RSU represents a contingent right to receive one share of the Issuer's Common Stock upon settlement.
F3 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.