Gregory K. Chow - 02 Mar 2026 Form 4 Insider Report for SUTRO BIOPHARMA, INC. (STRO)

Reporting relationship: CFO
Issuer ticker: STRO
Reported as of: 02 Mar 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 03 Mar 2026, 18:51:52 UTC
Prior SEC filing: 29 Dec 2025
Next SEC filing: 02 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ David Pauling as attorney-in-fact

Key filing fact

Gregory K. Chow filed Form 4 for SUTRO BIOPHARMA, INC. (STRO) on 03 Mar 2026.

Key facts

This page summarizes Gregory K. Chow's Form 4 filing for SUTRO BIOPHARMA, INC. (STRO).
2 reported transactions and 2 derivative rows are listed below.
Accepted by SEC: 03 Mar 2026, 18:51.

Change

Previous filing in this sequence was filed on 29 Dec 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001761333 Primary reporting owner

Chow Gregory K.

Relationship: CFO
Address: C/O SUTRO BIOPHARMA, INC., 111 OYSTER POINT BOULEVARD, SOUTH SAN FRANCISCO
Signature: /s/ David Pauling as attorney-in-fact
Signature date: 03 Mar 2026

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

STRO transaction Derivative

Stock Option (right to buy)

Award

Transaction value: $0
Shares: +40,000
Change %
Price: $0.000000
Shares after: 40,000
Date: 02 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 40,000
Exercise price: $20.55
Footnotes: F1

STRO transaction Derivative

Restricted Stock Units (RSUs)

Award

Transaction value: $0
Shares: +5,000
Change %
Price: $0.000000
Shares after: 5,000
Date: 02 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 5,000
Exercise price
Footnotes: F2, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

1/48 of the total option award shall vest monthly, subject to the reporting person's continued service through each vesting date, with the first tranche vesting on April 1, 2026.

Footnote F2

Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.

Footnote F3

The RSUs shall vest as to 1/4 of the total award annually, with the first tranche vesting on March 1, 2027, subject to continued service through each vesting date.

SEC 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.