Gossamer Bio, Inc. — Form SCHEDULE 13D/A
Filed September 28, 2026 · analyzed by the Ownership Agent
SCHEDULE 13D/A
— Neutral
significance 28/100
What the filing says
Between 8/25/2026 and 9/28/2026, D.E. Shaw Co., L.P., D.E. Shaw Co., L.L.C., Valence Portfolios L.L.C., and David E. Shaw collectively sold approximately 1,281,000 shares of Gossamer Bio common stock. The filing reveals a dramatic price move: shares traded at $0.14–$0.21 in late August/early September, then jumped to $10–$12+ by mid-September (a ~76× appreciation in weeks). Total sale proceeds approx. $8.8M–$11.5M (estimated across weighted average prices). The amendment updates transaction disclosures for this period.
Why this rating
Significant insider selling by major holder during explosive stock rally, but D.E. Shaw likely already held material stake; proceeds are ~3–4% of $270.8M market cap. Filing is routine 13D/A amendment; does not disclose new ownership threshold, deal, or governance change. Stock volatility is notable but price appreciation benefits remaining holders.
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