SUTRO BIOPHARMA, INC.·4

Mar 6, 4:21 PM ET

Chung Jane 4

4 · SUTRO BIOPHARMA, INC. · Filed Mar 6, 2026

Research Summary

AI-generated summary of this filing

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Sutro BioPharma (STRO) CEO Jane Chung Exercises RSUs; 282 Shares Withheld

What Happened
Jane Chung, CEO of Sutro BioPharma, had 788 restricted stock units (RSUs) convert into 788 shares on 2026-03-04 (reported as exercise/conversion of a derivative, code M). The company withheld 282 of those shares to satisfy income tax withholding at an indicated value of $21.31 per share (reported as disposition, code F), totaling $6,009. Net shares issued to Chung after withholding were 506. The Form 4 was filed on 2026-03-06 (appears timely).

Key Details

  • Transaction date: 2026-03-04; Form 4 filed: 2026-03-06.
  • Items reported:
    • M: 788 shares acquired at $0.00 (RSU settlement).
    • F: 282 shares withheld/disposed at $21.31 for tax withholding = $6,009 (not an open-market sale).
  • Net shares received: 788 − 282 = 506 shares (based on the reported lines).
  • Shares owned after transaction: not disclosed in the provided excerpt.
  • Footnotes:
    • F1: Withheld shares satisfy income tax withholding; not a sale by the reporting person.
    • F2: Each RSU equals one share upon settlement.
    • F3: RSUs vest 1/4 annually; first tranche vested 3/4/2023 (this tranche vested per the schedule).

Context
This was an RSU settlement with net share withholding for taxes (a routine, non‑market transaction). Exercise price $0 indicates these were RSUs converting to stock, not option purchases. Withholding to cover taxes is common and does not by itself signal a buy or sell decision in the open market.

Insider Transaction Report

Form 4
Period: 2026-03-04
Chung Jane
DirectorChief Executive Officer
Transactions
  • Exercise/Conversion

    Common Stock

    2026-03-04+78821,567 total
  • Tax Payment

    Common Stock

    [F1]
    2026-03-04$21.31/sh282$6,00921,285 total
  • Exercise/Conversion

    Restricted Stock Units (RSUs)

    [F2][F3]
    2026-03-047880 total
    Exp: 2026-03-04Common Stock (788 underlying)
Footnotes (3)
  • [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 restricted stock units; does not represent a sale by the reporting person.
  • [F2]Each RSU represents a contingent right to receive one (1) share of the Issuer's Common Stock upon settlement.
  • [F3]The RSUs vested or vest as to 1/4 of the total award annually, with the first tranche vested on March 4, 2023, subject to continued service through each vesting date.
Signature
/s/ David Pauling as attorney-in-fact|2026-03-06

Documents

1 file
  • 4
    form4-03062026_090306.xmlPrimary