Welcome to our dedicated page for SUTRO BIOPHARMA SEC filings (Ticker: STRO), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Sutro Biopharma filings document the regulatory record of a clinical-stage oncology biotechnology company developing site-specific antibody-drug conjugates. Its SEC disclosures cover operating and financial results, research and development priorities, clinical and regulatory updates for ADC programs, collaboration-related matters, risk factors, and capital-structure activity involving its common stock.
The company’s filings also include definitive proxy materials on shareholder voting, board matters, executive compensation and equity awards. Form 8-K reports document material events such as agreement terminations, restructuring costs, Nasdaq listing-rule notices and compliance updates, and other corporate actions affecting governance, reporting status and financing flexibility.
SUTRO BIOPHARMA, INC. executive David Pauling, Chief Administrative Officer and General Counsel, reported equity transactions tied to restricted stock units on March 4, 2026. He exercised 675 RSUs, each converting into one share of common stock, and received 675 shares at a stated price of $0.00 per share.
To cover income tax withholding on this vesting, 277 common shares were withheld by the company at $21.31 per share, which the footnote clarifies does not represent a sale by Pauling. After these transactions, he directly owned 9,748 shares of Sutro Biopharma common stock.
SUTRO BIOPHARMA, INC. director and Chief Executive Officer Jane Chung reported equity award activity involving restricted stock units and common stock. On March 4, 2026, 788 restricted stock units were exercised or converted into 788 shares of common stock at a stated price of $0.00 per share, reflecting settlement of previously granted RSUs.
On the same date, 282 shares of common stock were withheld at a price of $21.31 per share to satisfy income tax withholding and remittance obligations related to the net settlement of the RSUs, and the footnote clarifies this does not represent a sale by the reporting person. After these transactions, Jane Chung directly owned 21,285 shares of Sutro Biopharma common stock.
SUTRO BIOPHARMA, INC. Chief Administrative Officer and General Counsel David Pauling reported multiple equity transactions. He acquired common stock through the vesting and settlement of restricted stock units (RSUs) and received new awards of 4,200 RSUs and stock options for 33,600 shares. Some common shares (970 and 551) were withheld at prices of $20.55 and $20.47 to satisfy tax obligations in connection with RSU settlements, which the company notes do not represent market sales by Pauling.
Sutro Biopharma Chief Scientific Officer Hans-Peter Gerber reported multiple equity transactions involving restricted stock units (RSUs), stock options and common shares. On March 1 and 2, 2026, RSU vesting led to the acquisition of 1,125 and 2,843 shares of common stock through derivative exercises at a stated price of $0.00 per share.
To cover income tax withholding obligations related to these RSU settlements, the issuer withheld 463 and 1,170 shares of common stock at prices of $20.47 and $20.55 per share, which the footnotes clarify do not represent sales by the reporting person. Gerber also received direct grants of 5,000 RSUs and a stock option for 40,000 shares, each subject to time-based vesting schedules described in the footnotes, including annual RSU vesting in four tranches and a stock option that vests in 1/48 monthly installments beginning on April 1, 2026.
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.
Sutro Biopharma CEO Jane Chung reported multiple equity award and vesting transactions. She received a grant of 40,000 Restricted Stock Units (RSUs) and a stock option for 175,000 shares, both with service-based vesting schedules over time.
RSUs previously granted to her vested on March 1 and March 2, 2026, and were settled into common stock through several derivative exercises. In connection with these vestings, a total of 2,779 shares at $20.55 and 1,271 shares at $20.47 of common stock were withheld by the company to cover income tax obligations, which the footnotes state do not represent sales by the reporting person.
Sutro Biopharma reports institutional holdings by BVF group. As of February 18, 2026, the filing shows BVF beneficially owned 668,693 shares, BVF2 owned 488,916 shares and Trading Fund OS owned 75,359 shares.
The filing states aggregate positions that certain BVF-related entities may be deemed to beneficially own: 1,157,609 shares held by BVF GPH and 1,251,788 shares attributed to Partners, BVF Inc. and Mark N. Lampert, representing approximately 7.6% of the 16,432,271 shares outstanding reported in the prospectus supplement as of February 10, 2026.
Sutro Biopharma, Inc. filed an amended Schedule 13G/A showing that Suvretta Capital Management, LLC, Averill Master Fund, Ltd., and Aaron Cowen no longer beneficially own any of its common stock. As of the event date of 12/31/2025, each reporting person discloses beneficial ownership of 0 shares, representing 0% of Sutro’s common stock, with no sole or shared voting or dispositive power.
The filing confirms that the group now owns 5% or less of the class. It also notes that all securities previously reported were directly owned by advisory clients of Suvretta Capital Management, LLC, and that no individual advisory client is deemed to own more than 5% of the common stock. The certification states that the securities were not acquired and are not held for the purpose of changing or influencing control of Sutro Biopharma.
Sutro Biopharma, Inc. investors received an update on institutional ownership as Suvretta Capital Management, Averill Master Fund, and Aaron Cowen reported no beneficial ownership of the company’s common stock. Each reporting person lists 0 shares beneficially owned, representing 0% of the class, with no sole or shared voting or dispositive power.
The filing notes that all securities previously reported are directly owned by advisory clients of Suvretta Capital Management, and that none of those clients may be deemed to beneficially own more than 5% of Sutro’s common stock. The reporting persons also certify that the securities are not held to change or influence control of the company.
Sutro Biopharma, Inc. entered an underwriting agreement on February 9, 2026 to sell 7,868,383 shares of common stock at $13.98 per share in an underwritten public offering under its existing shelf registration. The company estimates gross proceeds of about $110.0 million, which, combined with its cash, cash equivalents and marketable securities as of January 1, 2026, is expected to bring total capital resources to approximately $251.4 million.
Sutro plans to use the net proceeds primarily for general corporate purposes, including research, clinical and process development and manufacturing of product candidates, working capital, potential acquisitions or investments, capital expenditures and other corporate needs. Based on its planned use of funds, Sutro estimates this capital will fund operating and capital needs into the second quarter of 2028. The offering is expected to close on February 11, 2026, subject to customary conditions. Sutro is also releasing an updated corporate presentation, which will be available on its website and furnished as an exhibit.