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. director Jon Marc Wigginton received a grant of stock options covering 10,000 shares of common stock on June 5, 2026. The options have an exercise price of $26.09 per share and represent equity-based compensation rather than an open-market trade.
According to the vesting terms, 8.33% of the award vests monthly starting on July 5, 2026, subject to his continued service. The options will be fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027. Following this grant, he holds 10,000 options directly.
Sutro Biopharma director Daniel H. Petree received a grant of stock options for 10,000 shares of Common Stock on June 5, 2026. The options have an exercise price of $26.09 per share and expire on June 5, 2036.
The award vests monthly as to 8.33% of the total, starting July 5, 2026, provided he continues to provide services. The options will be fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027.
Sutro Biopharma director James P. Panek received a grant of stock options covering 10,000 shares of common stock. The options have an exercise price of $26.09 per share and expire on June 5, 2036. They vest 8.33% monthly starting July 5, 2026 and are fully exercisable by the earlier of the 2027 annual stockholders meeting or June 5, 2027, assuming continued service.
Sutro Biopharma director Joseph M. Lobacki received a grant of stock options for 10,000 shares of common stock. The options carry an exercise price of $26.09 per share and expire on June 5, 2036. Vesting is scheduled at 8.33% of the total award each month starting July 5, 2026, and the grant becomes fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, subject to his continued service.
Sutro Biopharma director Jagpal Sukhi received a new stock option grant for 10,000 shares of common stock. The option has an exercise price of $26.09 per share and expires on June 5, 2036. This is a compensation-related award rather than an open-market trade.
The option vests over time, with 8.33% of the total award vesting monthly, starting on July 5, 2026. The grant will be fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, assuming continued service. After this grant, Sukhi holds options to acquire 10,000 shares directly.
Sutro Biopharma director Heidi Hunter received a grant of stock options for 10,000 shares of Common Stock on June 5, 2026. The options have an exercise price of $26.09 per share and expire on June 5, 2036. Vesting occurs in 8.33% monthly installments starting July 5, 2026, and the award is fully vested by the earlier of the 2027 annual stockholders meeting or June 5, 2027.
Sutro Biopharma director Michael Dybbs received a new stock option grant. He was awarded options for 10,000 shares of common stock at an exercise price of $26.09 per share. These options were granted at no upfront cost and increase his potential future equity stake.
The award vests monthly at 8.33% of the total starting on July 5, 2026, and will be fully vested and exercisable on the earlier of the company’s 2027 annual stockholders meeting or June 5, 2027, as long as he continues providing service.
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.
Sutro Biopharma, Inc. reported the results of its 2026 Annual Meeting of Stockholders held on June 5, 2026. Stockholders elected directors Jane Chung, Connie Matsui, and James Panek, each receiving more votes “for” than “withheld,” with broker non-votes also recorded.
Stockholders also approved two additional proposals, with one receiving 13,893,289 shares voted for, 501 against, and 5,883 abstaining, and another receiving 11,329,946 shares for, 22,412 against, 6,452 abstentions, and 2,540,863 broker non-votes.
Sutro Biopharma CFO Gregory K. Chow exercised equity awards and increased his direct stake in the company. On June 2, 2026, he exercised Restricted Stock Units (RSUs) covering 2,500 shares of Common Stock, with no shares sold in this filing. Following the transaction, he directly holds 4,725 shares of Common Stock and 7,500 RSUs, each representing the right to receive one share upon settlement. Footnotes state that tax withholding obligations were satisfied in cash rather than by withholding shares, and that his total Common Stock holdings include 250 shares acquired under the company’s employee stock purchase plan.