Smith Robert Paul JR Stock Option Grant

Robert Paul Smith Jr., Chief Commercial Officer of Gossamer Bio, Inc., was granted a stock option on August 24, 2026, for 5,800,051 shares of Common Stock at a price of $0.175 per share. The option vests under specific conditions related to FDA approval of seralutinib. If FDA approval is not obtained within two years of the grant date, a portion of the option will vest monthly thereafter. The option expires on August 23, 2036. This transaction is reported on Form 4.