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.
The Sutro Biopharma, Inc. (STRO) SEC filings page on Stock Titan provides access to the company’s public filings as reported to the U.S. Securities and Exchange Commission. Sutro is a clinical-stage oncology company focused on antibody-drug conjugates (ADCs), and its filings offer detailed insight into how it reports financial results, manages risk, and discloses material events related to its ADC pipeline and corporate operations.
Investors can review current reports on Form 8-K, where Sutro has disclosed items such as quarterly financial results, organizational restructuring designed to prioritize its ADC programs and extend its cash runway, and notices from Nasdaq regarding minimum bid price compliance. Additional 8-K filings describe actions like the 1-for-10 reverse stock split of its common stock and subsequent confirmation that the company regained compliance with Nasdaq Listing Rule 5450(a)(1).
Beyond event-driven 8-Ks, users can use this page to locate annual reports on Form 10-K and quarterly reports on Form 10-Q, which typically contain more extensive information on Sutro’s research and development activities, collaboration agreements, and financial condition. For those tracking management and ownership changes, insider transaction reports on Form 4 and related filings can also be accessed to see how executives and directors transact in STRO shares.
Stock Titan enhances these documents with AI-powered summaries that highlight key points from lengthy filings, helping readers quickly understand topics such as pipeline updates, restructuring charges, collaboration revenue, and listing status developments. Real-time updates from EDGAR ensure that new Sutro Biopharma filings appear promptly, while AI-generated overviews provide a starting point for deeper review of the full SEC documents.
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, LLCMichael 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.
Sutro Biopharma (STRO) filed its Q3 2025 report, showing revenue of $9.7 million, up from $8.5 million a year ago. For the nine months, revenue reached $90.8 million versus $47.2 million, driven by collaboration activity including accelerated recognition tied to changes in partner programs. Q3 net loss was $56.9 million compared to $48.8 million, reflecting restructuring charges of $9.6 million in the quarter and $49.0 million year-to-date.
Unrestricted cash, cash equivalents and marketable securities totaled $167.6 million as of September 30, 2025, and management expects this to fund operations for at least 12 months after filing. Total assets were $209.7 million; the company reported a stockholders’ deficit of $87.3 million, largely due to an accumulated deficit of $931.2 million and a deferred royalty obligation of $209.9 million. Deferred revenue declined to $12.7 million from $82.3 million as obligations were satisfied. Sutro is prioritizing three preclinical ADC programs, exiting its internal GMP facility by year-end, and has announced workforce reductions that cumulatively approximate two-thirds. The company received a Nasdaq minimum bid price notice with a compliance period through December 17, 2025.
Sutro Biopharma (STRO)Exhibit 99.1. The company states the information under Item 2.02, including Exhibit 99.1, is being furnished and not filed under the Exchange Act, and is not subject to Section 18 liabilities nor incorporated by reference except as expressly stated.
Sutro Biopharma (STRO): Insider transaction reported. A company officer (Chief Administrative Officer & General Counsel) purchased 12,504 shares of Common Stock on 10/15/2025 at $0.7992 per share, according to a Form 4 filing.
Following the transaction, the officer directly beneficially owns 71,737 shares. The total includes 2,500 shares acquired through the company’s Employee Stock Purchase Plan, as noted in the filing’s explanation.
Sutro Biopharma (STRO) reported an insider share purchase. A director bought 50,000 shares of common stock on 10/15/2025 at a price of $0.799 per share, according to a Form 4 filing. Following the transaction, the reporting person beneficially owns 50,000 shares, held directly.
Sutro Biopharma (STRO) disclosed an insider stock purchase by its Chief Executive Officer and Director, Jane Chung. On 10/15/2025, the reporting person purchased 12,500 shares of common stock at $0.8009 per share (transaction code P). Following this transaction, the reporting person beneficially owned 122,850 shares, held in direct ownership.
No derivative securities were reported in this filing.