Spero Therapeutics, Inc. — Director's Dealing 2017

Nov 1, 2017

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Spero Therapeutics, Inc. (SPRO)
CIK: 0001701108
Period of Report: 2017-11-01

Reporting Person: THOMAS FRANK E (Director)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option (Right to Buy)	$5.90	2027-07-16	Common Stock (30515)		Direct

Footnotes

F1: The shares underlying this option vest as to 25% on July 17, 2018, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service through the applicable vesting date.

F2: The number of underlying shares of common stock and the exercise price reported reflect a 1-for-6.0774 reverse stock split of the Issuer's common stock effected on October 20, 2017.