Spero Therapeutics is trading 12.72% up at $1.28, with no new company-specific announcement identified for September 22, 2026.
- The latest notable filing was an S-3 effectiveness notice dated September 10.
- Recent coverage focused on earlier financing, clinical-development, and analyst-target news rather than a fresh catalyst.
- The move appears consistent with broader risk-on sentiment, although today’s market gains are relatively modest.