Sutro Biopharma (STRO) CFO awarded 40,000 options and 5,000 RSUs

Rhea-AI Filing Summary

SUTRO BIOPHARMA, INC. reported that its CFO, Gregory K. Chow, received new equity awards. He was granted stock options covering 40,000 shares of common stock at an exercise price of $0.00 per share, and 5,000 Restricted Stock Units (RSUs), both held directly.

According to the vesting terms, 1/48 of the stock option award vests monthly, starting on April 1, 2026, contingent on his continued service. The 5,000 RSUs vest in four equal annual installments, with the first tranche vesting on March 1, 2027, also subject to continued service, and each RSU represents one share upon settlement.

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^*

Chow Gregory K.

(Last) (First) (Middle)

C/O SUTRO BIOPHARMA, INC.

111 OYSTER POINT BOULEVARD

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CFO

3. Date of Earliest Transaction (Month/Day/Year)
03/02/2026

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

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
Stock Option (right to buy)	$20.55	03/02/2026		A		40,000		(1)	03/02/2036	Common Stock	40,000	$0	40,000	D
Restricted Stock Units (RSUs)	(2)	03/02/2026		A		5,000		(3)	03/01/2030	Common Stock	5,000	$0	5,000	D

Explanation of Responses:

1. 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.

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

3. 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.

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	03/03/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transactions did STRO CFO Gregory Chow report on this Form 4?

Gregory Chow reported acquisitions of equity awards, not open-market trades. He received 40,000 stock options and 5,000 RSUs, both at an exercise or purchase price of $0.00 per share, as part of his compensation.

How many stock options did the STRO CFO receive and what are the terms?

The CFO received 40,000 stock options with a $0.00 exercise price. 1/48 of the total award vests monthly, starting on April 1, 2026, and vesting is conditioned on his continued service with Sutro Biopharma through each vesting date.

What Restricted Stock Units (RSUs) were granted to STRO CFO Gregory Chow?

Gregory Chow was granted 5,000 RSUs. Each RSU represents a contingent right to receive one share of Sutro Biopharma common stock upon settlement, providing potential future share ownership if all vesting conditions and continued service requirements are satisfied over time.

What is the vesting schedule for Gregory Chow’s RSUs at Sutro Biopharma (STRO)?

The 5,000 RSUs vest in four equal annual installments. The first 1/4 vests on March 1, 2027, with the remaining tranches vesting annually thereafter, subject to Gregory Chow’s continued service through each applicable vesting date.

Are the equity awards to STRO’s CFO direct or indirect holdings?

Both the 40,000 stock options and 5,000 RSUs are reported as direct holdings. The Form 4 does not reference any intermediary entities or trusts, so the awards are attributed directly to Gregory K. Chow’s beneficial ownership.

Do these STRO Form 4 transactions involve any stock sales by the CFO?

No, the Form 4 reflects only grants or awards of options and RSUs, not sales. The transaction code is “A” for acquisition, and the filing shows no reported disposals or open-market sales of Sutro Biopharma common stock by the CFO.