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. is the issuer in Amendment No. 5, which updates reported ownership and voting and dispositive authority over its common stock. D. E. Shaw Valence Portfolios, L.L.C. reports 358,693 shares beneficially owned, approximately 5.9% of the class; Cogence beneficially owns 14,190 shares, approximately 0.2%. D. E. Shaw & Co., L.P. and D. E. Shaw & Co., L.L.C. each report shared voting power over 369,459 shares and shared dispositive power over 289,551 shares. Reporting person David E. Shaw may be deemed to share those powers but disclaims beneficial ownership.
The reported amounts include shares sold by certain reporting persons or affiliates before the amendment, because voting power over those shares was retained for the October Meeting under custodial account measures in place as of September 14, 2026, the meeting's record date. Gossamer Bio had 6,116,391 common shares issued and outstanding as of September 14, 2026, reflecting the reverse stock split.
Gossamer Bio, Inc. (GOSS) ownership amendment updates beneficial-ownership figures following the issuer’s 1-for-80 reverse stock split, effective September 10, 2026. Valence reported 296,858 common shares, approximately 4.9% of the class, and ceased to be a beneficial owner of more than 5% on September 24, 2026; Cogence reported 15,190 shares, approximately 0.2%.
D. E. Shaw & Co., L.P., the investment adviser, D. E. Shaw & Co., L.L.C., the manager, and David E. Shaw may be deemed to share voting and dispositive power over 312,048 shares, or 5.1%; each disclaims beneficial ownership as stated. Gossamer Bio had 6,116,391 common shares outstanding as of September 14, 2026. The amendment also says that, as a result of the split, Valence and Cogence maintained open short positions referencing 44,364 and 2,290 common shares, respectively.
Gossamer Bio, Inc. received a Nasdaq letter on September 25, 2026, stating that it had regained compliance with the minimum bid price requirement for continued listing on the Nasdaq Global Select Market and that the matter was closed. The company had failed to maintain a minimum bid price of $1.00 or more for 30 consecutive business days. It effected a 1-for-80 reverse stock split on September 10, 2026, and its common stock began trading on a split-adjusted basis on September 11, 2026.
Gossamer Bio, Inc. director Sandra Milligan was granted a stock option covering 10,000 shares of common stock on September 23, 2026, with an exercise price of $10.99 per share. The reported post-grant position in this option was 10,000 underlying shares, and the option expires September 22, 2036. All shares subject to the option become fully vested and exercisable on the first anniversary of the grant, subject to Milligan's continued board service through that date. No Rule 10b5-1 plan is reported.
Gossamer Bio, Inc. director Daniel Thomas O received a stock-option award covering 10,000 common shares on September 23, 2026, with an exercise price of $10.99 per share. The options become fully vested and exercisable on the first anniversary of the grant, subject to his continued service on the board through that date, and expire September 22, 2036. No Rule 10b5-1 plan is reported.
Gossamer Bio, Inc. director Gregory Austin Ciongoli received a grant of stock options covering 30,000 common shares on September 23, 2026. The options have a $10.99 exercise price per share. One thirty-sixth vests on the last day of each one-month period thereafter, subject to continuous service. The options expire September 22, 2036; no Rule 10b5-1 plan is reported.
Gossamer Bio, Inc. (GOSS) director Drynan Skye received an award of 10,000 stock options on September 23, 2026. The options have a $10.99 exercise price and expire September 22, 2036. The entire award becomes fully vested and exercisable on the first anniversary of the grant date, subject to Drynan Skye’s continued service on the board. No Rule 10b5-1 plan is reported.
Gossamer Bio, Inc. reported that director John D. Quisel acquired an option award covering 10,000 shares of common stock on September 23, 2026. The options have an exercise price of $10.99 per share and expire September 22, 2036. They become fully vested and exercisable on the first anniversary of the grant date, subject to his continued service on the board through that date.
Gossamer Bio, Inc. director Russell J. Cox received an award of options covering 10,000 shares of common stock on September 23, 2026, with an exercise price of $10.99 per share. Cox held 10,000 options after the grant. The full grant becomes vested and exercisable on the first anniversary of the grant date, subject to his continued board service through that date; the options expire September 22, 2036. No Rule 10b5-1 plan is reported.
Gossamer Bio, Inc. reported a grant to director Nathan Steven D of stock options covering 10,000 shares of common stock on September 23, 2026. The options have an exercise price of $10.99 per share and expire September 22, 2036. They become fully vested and exercisable on the first anniversary of the grant, subject to the director’s continued board service through that date. No Rule 10b5-1 plan is reported.