June 23, 2026 · Form 4 insider transaction
THOMAS FRANK E bought 20,000 shares of Spero Therapeutics, Inc. at $0.00 per share, a transaction worth N/A. The trade was recorded as grant or award and disclosed on an SEC Form 4, filed 2 days after the transaction.
The shares underlying this option will vest and become exercisable in full on June 23, 2027 subject to the Reporting Person's continued service as a director through the vesting date.