D. E. Shaw & Co. Reports 9.5% Stake in Gossamer Bio Following Debt Exchange Offer

On June 11, 2026, D. E. Shaw & Co., L.P. and affiliated reporting persons, including Dr. David E. Shaw, filed a Schedule 13D reporting a 9.5% beneficial ownership interest in Gossamer Bio, Inc. (GOSS), totaling 46,485,295 shares of Common Stock. This significant position was primarily established through an Exchange Offer finalized on June 4, 2026. Under the terms of the offer, reporting entities D. E. Shaw Valence Portfolios and D. E. Shaw Cogence Portfolios exchanged existing 5.00% Convertible Senior Notes due 2027 for a combination of new 7.50% Convertible Senior Secured First Lien Notes due 2030, Common Shares, and Purchase Warrants. Specifically, the reporting persons received 48,107,644 new shares in connection with the exchange. The reporting persons also entered into voting agreements to support various stockholder proposals, including a reverse stock split and an increase in authorized shares. While the reporting persons currently hold a substantial stake, they have recently engaged in modest sales of shares on the open market between June 8 and June 11, 2026, as detailed in the filing's Schedule I.