Sutro (STRO) CFO Gregory Chow Converts 2,500 Derivative Shares

What Happened Gregory K. Chow, Chief Financial Officer of Sutro Biopharma (STRO), reported the conversion/exercise of 2,500 derivative shares into common stock on June 2, 2026. The filing shows 2,500 shares acquired at $0.00 (conversion/settlement) and a matching 2,500-share derivative disposition at $0.00. Footnotes indicate these relate to awards that vested (RSUs) and that tax withholding was satisfied in cash rather than by withholding shares.

Key Details

• Transaction date: 2026-06-02; transaction code M (exercise/conversion of derivative).
• Reported amounts: 2,500 shares acquired @ $0.00; 2,500 shares disposed @ $0.00 (derivative entry).
• Price/value: $0.00 per share (reflects RSU conversion/settlement, not an open-market purchase).
• Shares owned after transaction: not specified in the provided excerpt of the Form 4.
• Notable footnotes:
  • F1: Reporting person elected cash payment for tax withholding (no withholding shares).
  • F3/F4: Each RSU converts to one common share; award vests annually 1/4th with first tranche vesting 6/2/2026.
  • F2: The reported total includes 250 shares from the employee stock purchase plan (ESPP) exempt from Form 4 reporting rules.
• Timeliness: Filing date and period both 2026-06-02; no late filing indicated.

Context This filing reflects equity award vesting/derivative conversion (RSUs converting into common stock) rather than an open-market purchase or sale. Because taxes were paid in cash per the filing, there is no indication shares were sold to cover withholding. Vesting/settlement entries are routine for executives and do not by themselves signal a buy or sell decision.