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 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.
Sutro Biopharma, Inc. is conducting a primary offering of 7,868,383 shares of common stock at $13.98 per share, raising gross proceeds of $109,999,994. After $6,600,000 in underwriting discounts and commissions, Sutro expects approximately $103,399,995 in proceeds before expenses and estimates net proceeds of about $102.7 million.
The company plans to use the cash, together with existing balances, for general corporate purposes, including research, clinical and process development, manufacturing, working capital, potential acquisitions or investments, and capital expenditures. Combined with cash, cash equivalents and marketable securities as of January 1, 2026 and the additional $110.0 million before costs, Sutro expects to have approximately $251.4 million in capital resources, which it estimates will fund operations into the second quarter of 2028.
As context, 8,563,888 shares of common stock were outstanding as of September 30, 2025. The offering price of $13.98 per share is expected to result in immediate dilution of $13.04 per share to new investors, based on an as adjusted net tangible book value of $0.94 per share after the transaction. Leerink Partners LLC, TD Securities (USA) LLC and LifeSci Capital LLC are underwriting the deal, and the company, its directors and executive officers are subject to 60‑day and 90‑day lock-up periods, respectively, with specified exceptions.
Affinity Asset Advisors, LLC and its managing member Michael Cho report beneficial ownership of 748,382 shares of Sutro Biopharma, Inc. common stock, equal to approximately 8.8% of the company’s outstanding shares based on 8,519,392 shares outstanding as of December 3, 2025.
The shares are held by Affinity Healthcare Fund, LP, for which Affinity Asset Advisors serves as investment manager. As of the current reporting date, the reporting persons have sole voting and dispositive power over these shares and certify that the position is held in the ordinary course of business, without the purpose or effect of changing or influencing control of Sutro Biopharma.
A shareholder of STRO has filed a notice of proposed sale under Rule 144 for up to 8,929 shares of common stock through Morgan Stanley Smith Barney LLC on or around 01/20/2026, to be sold on the NASDAQ. The filing lists an aggregate market value of $130,961.76 for these shares and notes that 8,513,529 shares of this class were outstanding. The securities to be sold were acquired via a mix of stock option exercise and restricted stock awards from the issuer in 2025–2026, some paid in cash and some noted as not applicable for cash payment. By signing, the seller represents they are not aware of undisclosed material adverse information about the issuer’s operations.
Sutro Biopharma, Inc. reported that it has regained compliance with Nasdaq’s minimum bid price requirement for continued listing on The Nasdaq Global Market. Nasdaq’s Listing Qualifications staff confirmed that, as of December 16, 2025, the closing bid price of Sutro’s common stock had been at least $1.00 per share for 10 consecutive business days and that the company satisfies all other applicable listing criteria. This means the prior listing deficiency has been resolved and the related matter is now closed.
The company had previously been notified on June 20, 2025 that its stock had traded below $1.00 per share for 30 consecutive business days, putting it out of compliance with Nasdaq Listing Rule 5450(a)(1). The new notice confirms that Sutro has successfully corrected this issue and remains listed on The Nasdaq Global Market.
Sutro Biopharma CEO and director Jane Chung reported the vesting and settlement of restricted stock units on 12/12/2025. She received 2,500 shares of common stock at an exercise price of $0, and 894 shares were withheld by the company at $8.015 per share to cover tax obligations, which the filing states does not represent a sale by her. Following these transactions, she directly owns 13,891 shares of common stock and 5,000 RSUs, each RSU representing the right to receive one share upon settlement. The award vests in annual quarters, with the first tranche having vested on December 1, 2024. All share and dollar amounts reflect a 1-for-10 reverse stock split of Sutro Biopharma common stock that became effective on December 3, 2025.