Welcome to our dedicated page for Gossamer Bio SEC filings (Ticker: GOSS), 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.
Gossamer Bio filings document a clinical-stage biopharmaceutical issuer centered on seralutinib for PAH and PH-ILD. Form 8-K reports cover operating and financial results, Phase 3 PROSERA clinical disclosures, material agreements, unregistered equity issuances, resource-allocation actions, and Nasdaq listing-compliance notices involving its common stock.
Proxy materials describe board governance, shareholder voting matters, executive compensation, equity awards, and incentive-plan administration. The filing record also documents capital-structure matters and formal disclosures connected to a late-stage pulmonary hypertension development company.
Gossamer Bio, Inc. received an amended Schedule 13G filing showing that BlackRock, Inc. beneficially owns 15,065,708 shares of its common stock as of 12/31/2025. This position represents 6.5% of Gossamer Bio’s outstanding common shares.
BlackRock reports sole voting power over 14,859,077 shares and sole dispositive power over 15,065,708 shares, with no shared voting or dispositive power. The filing explains that these securities are held by certain BlackRock business units and that various underlying persons have rights to dividends or sale proceeds, but no individual holds more than five percent of the total outstanding shares.
BlackRock certifies that the shares were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of Gossamer Bio.
Gossamer Bio (GOSS) furnished a Form 8-K announcing it issued a press release reporting financial results for the quarter ended September 30, 2025. The press release is included as Exhibit 99.1.
The company noted that the information in this item, 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 specifically stated. The report was signed by Bryan Giraudo, Chief Financial Officer and Chief Operating Officer.
Gossamer Bio (GOSS) reported Q3 2025 results, showing higher collaboration revenue but wider losses. Revenue was $13.3 million for the quarter, up from $9.5 million a year ago, driven by revenue from contracts with collaborators. For the nine months, revenue was $34.7 million versus $105.3 million last year, when results included $88.8 million of license revenue.
The company posted a Q3 net loss of $48.2 million (basic/diluted loss per share $0.21), compared with a $30.8 million loss a year earlier, as research and development expenses rose to $45.5 million. Year to date, operating cash flow was negative $123.0 million.
As of September 30, 2025, cash and cash equivalents were $8.9 million and marketable securities were $171.3 million. Total assets were $208.8 million against total liabilities of $291.2 million, resulting in a stockholders’ equity (deficit) of $(82.3) million. Long‑term convertible senior notes had a net carrying amount of $198.3 million. The company reports that Chiesi accounted for 100% of revenue during the nine‑month period under the collaboration agreement.
Robert Paul Smith Jr., identified as an Officer (Chief Commercial Officer) of Gossamer Bio, Inc. (GOSS), reported a securities acquisition on 10/01/2025. The filing shows an award of 162,500 performance stock units issued at $0 that will vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant, and subject to his continuous service to the company. The filing also discloses 25,000 shares held indirectly by a family trust. The Form 4 was submitted by one reporting person and signed by an attorney-in-fact on 10/02/2025.
Christian Waage, Executive Vice President, Tech Ops and Admin at Gossamer Bio, Inc. (GOSS), received a performance stock unit award of 125,000 shares on 10/01/2025. The award has a $0 purchase price and will vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant, subject to continuous service. Following the grant, Mr. Waage is reported to beneficially own 710,934 shares directly, plus 45,892 shares held by a family trust and 22,222 held in a trust for his son. The Form 4 was signed by an attorney-in-fact on 10/02/2025.
Gossamer Bio, Inc. (GOSS) Chief Operating and Financial Officer Bryan Giraudo reported an award of 181,250 performance stock units on 10/01/2025. The award is a non‑cash grant that will vest in full upon the earlier of: approval of a new drug application for seralutinib or a change in control, provided vesting occurs on or before the fourth anniversary of the grant and the reporting person remains in continuous service. Following the reported grant, Mr. Giraudo beneficially owns 273,987 shares directly and 480,010 shares indirectly through a family trust, for combined reported beneficial ownership disclosed on the form.
Richard Aranda, Chief Medical Officer of Gossamer Bio, Inc. (GOSS), reported receiving a performance stock unit award of 162,500 common stock units on 10/01/2025. The award carries a $0 purchase price and will vest in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, provided vesting occurs on or before the fourth anniversary of the grant date and subject to the reporting person’s continuous service. After the reported transaction, the filing shows 369,356 shares beneficially owned directly and 2,539 shares beneficially owned indirectly through a family trust. The filing was signed by an attorney-in-fact on 10/02/2025.
Hasnain Faheem, President & CEO and a director of Gossamer Bio, Inc. (GOSS), reported a non‑derivative acquisition dated 10/01/2025 of 437,500 performance stock units at a reported price of $0. After the award, the filing shows 557,793 shares beneficially owned directly and 5,408,073 shares beneficially owned indirectly through a family trust. The performance stock units will vest in full upon the earlier of the approval of a new drug application for seralutinib or a change in control, in either case on or before the fourth anniversary of the grant date, and are subject to the reporting person’s continuous service to the issuer. The Form 4 was signed on 10/02/2025 by an attorney‑in‑fact.
Caryn Peterson, Executive Vice President, Regulatory Affairs of Gossamer Bio, Inc. (GOSS), reported the acquisition of 125,000 performance stock units on 10/01/2025. The award is a performance stock unit grant that vests in full upon the earlier of (i) approval of a new drug application for seralutinib or (ii) a change in control, in either case on or before the fourth anniversary of the grant date, and is subject to the reporting person’s continuous service. After the transaction the reporting person beneficially owns 174,833 shares. The Form 4 was signed by an attorney-in-fact on 10/02/2025.
Gossamer Bio, Inc. issued 2,500,000 shares of common stock to Prana on September 24, 2025 as consideration for a Company Merger Option. The Company agreed that, upon exercise of the Merger Option at closing, it would issue up to an additional 1,500,000 shares. The agreement also provides for cash and stock milestone payments following achievement of specified regulatory and sales milestones, including potential issuance of up to approximately 6,688,964 additional shares of common stock. The number of milestone shares to be issued will be calculated by dividing the applicable milestone obligation value by the average closing price on the Nasdaq Global Select Market for the thirty consecutive trading days ending two trading days before achievement of the milestone. The transactions are being made in reliance on Section 4(a)(2) of the Securities Act of 1933.
Gossamer Bio, Inc. issued 2,500,000 shares of common stock to Prana on September 24, 2025 as consideration for a Company Merger Option. The Company agreed that, upon exercise of the Merger Option at closing, it would issue up to an additional 1,500,000 shares. The agreement also provides for cash and stock milestone payments following achievement of specified regulatory and sales milestones, including potential issuance of up to approximately 6,688,964 additional shares of common stock. The number of milestone shares to be issued will be calculated by dividing the applicable milestone obligation value by the average closing price on the Nasdaq Global Select Market for the thirty consecutive trading days ending two trading days before achievement of the milestone. The transactions are being made in reliance on Section 4(a)(2) of the Securities Act of 1933.