Daily close, T-120 (7/9/25) through T+5. Run-up high $11.47 on 12/9/25, low $3.08 on 7/9/25 (T-120 to T-1). FDA decision 12/24/25. Historical price action, not a forecast.
Positioning before the decision
On Dec 10, 2025, 14 days before the decision date, at-the-money options priced a move of ±49.6% through Jan 16, 2026 (the first listed expiry after the decision; ATM implied volatility 204%). The stock closed +75.5% at the first close across the decision and +96.3% five trading days on. A straddle priced weeks out covers ordinary movement plus the event, so this is the move the options market priced through that expiry, not the event-implied move alone. How this compares across 1,000+ decisions.
Yes. The FDA approved the application for YARTEMLEA (Narsoplimab) on December 24, 2025. The primary source is linked on this page.
What was YARTEMLEA (Narsoplimab) under FDA review for?
The application covered Hematopoietic stem cell-associated TMA (HSCT-TMA). The FDA approved the application on December 24, 2025.
How did OMER stock react to the FDA decision?
On the decision day OMER moved +75.5%. That is the recorded reaction to this specific event -- historical measurement, not a prediction, and not investment advice.