SCHEDULE 13G 0001404574 XXXXXXXX LIVE Common Stock, $0.0001 par value per share 02/23/2026 0001728117 Gossamer Bio, Inc. 38341P102 3115 MERRYFIELD ROW SUITE 120 SAN DIEGO CA 92121 Rule 13d-1(c) 683 Capital Management, LLC DE 0 12331304 0 12331304 12331304 N 5.23 IA 683 Capital Partners, LP DE 0 12331304 0 12331304 12331304 N 5.23 PN Ari Zweiman X1 0 12331304 0 12331304 12331304 N 5.23 IN Gossamer Bio, Inc. 3115 MERRYFIELD ROW, SUITE 120, SAN DIEGO, CALIFORNIA 92121 683 Capital Management, LLC 683 Capital Partners, LP Ari Zweiman The principal business address for each of the Reporting Persons is 1700 Broadway, Suite 4200, New York, New York 10019. 683 Capital Management, LLC - DELAWARE 683 Capital Partners, LP - DELAWARE Ari Zweiman - UNITED STATES Y As of March 2, 2026, 683 Capital Partners, LP beneficially owned 8,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock which are currently exercisable. 683 Capital Management, LLC, as the investment manager of 683 Capital Partners, LP, may be deemed to have beneficially owned the 8,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock beneficially owned by 683 Capital Partners, LP. Ari Zweiman, as the Managing Member of 683 Capital Management, LLC, may be deemed to have beneficially owned the 8,000,000 shares of Common Stock and warrants to purchase 4,331,304 shares of Common Stock beneficially owned by 683 Capital Management, LLC. The following percentage is based on 231,456,247 shares of common stock ($0.0001 par value) outstanding as of October 31, 2025, as disclosed in the Issuer's Form 10-Q filed on November 5, 2025, plus 4,331,304 shares of Common Stock issuable upon exercise of currently exercisable warrants held by the Reporting Persons. As of March 2, 2026, the Reporting Persons may be deemed to have beneficially owned approximately 5.23% of the outstanding Common Shares. 5.23 See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. See Cover Pages Items 5-9. Y Y Y N See Exhibit A. Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. JOINT FILING AGREEMENT The undersigned hereby agree that the statement on Schedule 13G with respect to the shares of Common Stock, par value $0.0001 per share, of Gossamer Bio, Inc. dated as of March 2, 2026 is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(2) under the Securities Exchange Act of 1934, as amended. Dated: March 2, 2026 683 CAPITAL MANAGEMENT, LLC By: /s/ Ari Zweiman Ari Zweiman, Managing Member 683 CAPITAL PARTNERS, LP By: /s/ Ari Zweiman Ari Zweiman, Authorized Person /s/ Ari Zweiman Ari Zweiman 683 Capital Management, LLC Ari Zweiman 03/02/2026 683 Capital Partners, LP Ari Zweiman 03/02/2026 Ari Zweiman Ari Zweiman 03/02/2026