Gossamer Bio Announces 1-for-80 Reverse Stock Split

What Happened

• Gossamer Bio, Inc. (GOSS) filed an 8‑K (dated Sept 9, 2026) announcing the Board selected a 1-for-80 reverse stock split, which is expected to become effective Sept 10, 2026 at 11:59 p.m. Eastern Time. Shares are expected to trade on a split-adjusted basis on the Nasdaq Global Select Market at market open on Sept 11, 2026 under the existing symbol "GOSS" with a new CUSIP 38341P201. The stockholders previously approved the ability to implement one of 30 reverse split ratios on July 14, 2026.

Key Details

• Reverse split ratio: 1-for-80 (every 80 pre-split shares will be combined into 1 post-split share).
• Effective timing and trading: Effective Sept 10, 2026 at 11:59 p.m. ET; split-adjusted trading begins at open on Sept 11, 2026; new CUSIP 38341P201.
• Authorized shares reduction: Authorized common shares reduced from 4,000,000,000 to 50,000,000; total authorized capital stock reduced from 4,070,000,000 to 120,000,000.
• Security adjustments: Conversion rates for outstanding convertible notes (including 5.00% Convertible Senior Notes due 2027 and 7.50% Convertible Senior Secured First Lien Notes due 2030), warrants, prefunded warrants, outstanding equity awards and shares reserved under equity plans will be proportionately adjusted to reflect the 1-for-80 split.
• Fractional shares: No fractional shares will be issued to holders of record; instead the company (and DTC at the participant level) will round up fractions to the nearest whole share. Brokers/nominees may use their own procedures.

Why It Matters

• The company says the reverse split is intended to help Gossamer regain compliance with Nasdaq’s minimum bid price requirement. A 1-for-80 split cuts the outstanding share count by 80x, which increases the per‑share price mathematically but does not change each holder’s ownership percentage.
• Investors should note that convertible securities, warrants and equity awards will be adjusted proportionately, and the dramatic reduction in authorized shares limits future dilution capacity unless the company later increases authorization.
• The filing cautions there is no guarantee the reverse split will produce a sustained stock-price increase or achieve Nasdaq compliance; effects on liquidity, trading volatility and perception can vary.