683 Capital Management Reports 9.99% Passive Stake in Gossamer Bio, Inc.

On June 11, 2026, 683 Capital Management, LLC, along with 683 Capital Partners, LP and Ari Zweiman, filed a Schedule 13G disclosing a significant new ownership stake in Gossamer Bio, Inc. (GOSS). The reporting persons collectively beneficially own 49,868,571 shares of common stock, representing 9.99% of the company. This aggregate position includes 39,504,484 shares of common stock, 9,102,055 shares issuable upon the exercise of warrants, and 1,262,032 shares issuable upon the conversion of convertible notes. The filing notes that the ownership percentage is capped at 9.99% due to beneficial ownership limitations contained in the indenture governing the convertible notes. 683 Capital Management, LLC serves as the investment manager for 683 Capital Partners, LP, while Ari Zweiman serves as the Managing Member. The acquisition was reported as a passive investment, with the reporting persons certifying that the securities were not acquired for the purpose of influencing or changing control of the issuer.