STOCK TITAN

Director at Sutro Biopharma (STRO) receives 10,000 stock options as equity grant

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Sutro Biopharma director Connie Matsui received a new stock option grant covering 10,000 shares of Common Stock. The option has an exercise price of $26.09 per share and was granted as a compensation award, not an open-market purchase or sale. It vests in monthly installments of 8.33% starting on July 5, 2026. The award becomes fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, assuming continued service.

Positive

  • None.

Negative

  • None.

Insights

Director received a routine stock option grant as equity compensation.

Connie Matsui, a director of Sutro Biopharma, was granted stock options for 10,000 shares of Common Stock at an exercise price of $26.09 per share. The Form 4 labels this as a grant or award acquisition, not a market transaction.

The options vest monthly at 8.33% starting on July 5, 2026, with full vesting by the earlier of the 2027 annual stockholders meeting or June 5, 2027, contingent on continued service. There are no sales, tax withholdings, or exercises reported, and derivativeSummary is empty, indicating only this new award is shown in this filing.

Insider MATSUI CONNIE
Role null
Type Security Shares Price Value
Grant/Award Stock Option (right to buy) 10,000 $0.00 --
Holdings After Transaction: Stock Option (right to buy) — 10,000 shares (Direct, null)
Footnotes (1)
  1. [object Object]
Stock options granted 10,000 options Grant covering 10,000 shares of Common Stock
Exercise price $26.09 per share Option exercise price for the 10,000-share award
Total options after grant 10,000 options Derivative securities owned following the reported transaction
Vesting start date July 5, 2026 First 8.33% monthly vesting tranche
Full vesting deadline Earlier of 2027 meeting or June 5, 2027 Award fully vested and exercisable by that time
Expiration date June 5, 2036 Option term end date
Stock Option (right to buy) financial
"security_title: Stock Option (right to buy)"
exercise price financial
"conversion_or_exercise_price: 26.0900"
The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.
vesting financial
"The option shall vest, subject to the reporting person's provision of service"
Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.
expiration date financial
"expiration_date: 2036-06-05T00:00:00.000Z"
The expiration date is the deadline after which a financial contract, such as an option or a futures agreement, is no longer valid or can be exercised. It matters to investors because it determines the timeframe during which they can take action or benefit from the contract, similar to how a coupon or a food item has a limited period of usefulness. Once the expiration date passes, the contract loses its value or ability to be used.
Common Stock financial
"underlying_security_title: Common Stock"
Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.
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SEC Form 4
FORM 4UNITED 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
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
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*
MATSUI CONNIE

(Last)(First)(Middle)
C/O SUTRO BIOPHARMA, INC.
111 OYSTER POINT BLVD.

(Street)
SOUTH SAN FRANCISCO CALIFORNIA 94080

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
SUTRO BIOPHARMA, INC. [ STRO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
Officer (give title below)Other (specify below)
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/05/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
CodeVAmount(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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Stock Option (right to buy)$26.0906/05/2026A10,000 (1)06/05/2036Common Stock10,000$010,000D
Explanation of Responses:
1. The option shall vest, subject to the reporting person's provision of service to the issuer on each vesting date, as to 8.33% of the total award monthly, with the first tranche vesting on July 5, 2026, and the award shall be fully vested and exercisable on the earlier of (i) the date of the issuer's 2027 annual stockholders meeting or (ii) June 5, 2027.
/s/ David Pauling as attorney-in-fact06/09/2026
** Signature of Reporting PersonDate
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.
* Form 4: SEC 1474 (03-26)

FAQ

What did Sutro Biopharma (STRO) report in this Form 4 for Connie Matsui?

Sutro Biopharma reported that director Connie Matsui received a grant of stock options covering 10,000 shares of Common Stock. The options are a compensation award and not an open-market trade, and they increase her potential future equity exposure.

How large is Connie Matsui’s new stock option grant at Sutro Biopharma (STRO)?

The grant covers 10,000 stock options, each for one share of Sutro Biopharma Common Stock. These options have an exercise price of $26.09 per share and represent additional potential ownership if she chooses to exercise them after vesting.

What are the vesting terms of Connie Matsui’s Sutro Biopharma stock options?

The options vest in monthly installments of 8.33%, beginning on July 5, 2026. They become fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, assuming she continues serving the company.

What is the exercise price and expiration date of Connie Matsui’s STRO stock options?

The stock options have an exercise price of $26.09 per share and an expiration date of June 5, 2036. She can only exercise them once they have vested and before they expire, subject to the plan’s rules.

Does this Form 4 show Connie Matsui buying or selling STRO shares on the market?

No, the Form 4 shows a grant of stock options, coded as a grant or award acquisition. It does not report any open-market purchases or sales of Sutro Biopharma Common Stock by Connie Matsui on the transaction date disclosed.

How many derivative securities does Connie Matsui hold after this transaction?

After the grant, the Form 4 shows 10,000 derivative securities (stock options) held following the transaction. This corresponds to options for 10,000 shares of Common Stock, reflecting the newly awarded grant reported in the filing.