Spero Therapeutics Establishes $100 Million At-The-Market Offering Program with Jefferies

Spero Therapeutics announced it has entered into an Open Market Sale Agreement with Jefferies LLC to establish a new at-the-market (ATM) offering program. This agreement allows the company to offer and sell shares of its common stock with an aggregate offering price of up to $100 million. Concurrently, Spero terminated its previous $75 million ATM sales agreement with Cantor Fitzgerald & Co.

Key Details

• New ATM Facility: The agreement, dated August 28, 2026, allows Spero to sell common stock from time to time at its discretion, contingent upon its S-3 registration statement becoming effective.
• Financial Terms: Jefferies will act as the sales agent for a commission of up to 3.0% of the gross proceeds from any shares sold under the program.
• Prior Agreement Terminated: The company terminated its prior $75 million ATM agreement with Cantor Fitzgerald & Co., effective August 28, 2026. No shares were sold under the Cantor agreement in fiscal years 2024 and 2025, and no termination penalties were incurred.