Spero Therapeutics, Inc. — Director's Dealing 2021

Dec 29, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Spero Therapeutics, Inc. (SPRO)
CIK: 0001701108
Period of Report: 2021-12-27

Reporting Person: Mahadevia Ankit (Director, CEO and President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-12-27	Common Stock	M	8000	$5.90	Acquired	152036	Direct
2021-12-27	Common Stock	S	8000	$14.5833	Disposed	144036	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2021-12-27	Stock Option (Right to Buy)	$5.90	M	8000	Disposed	2027-07-05	Common Stock (8000)	Direct

Footnotes

F1: All transactions reported on this Form 4 were made pursuant to a previously adopted Rule 10b5-1 trading plan. Specifically, the transactions reported herein relate to option exercises and related sales (totaling 8,000 shares).

F2: Amount includes 65,817 shares of common stock held by the Mahadevia-Mehta Family Trust, of which the Reporting Person is a trustee. Amount also includes 78,219 restricted stock units ("RSUs") held by the Reporting Person. Each RSU represents the right to receive one share of common stock upon vesting. The RSUs vest in four equal annual installments beginning on August 26, 2022, subject to the Reporting Person's continued service through the applicable vesting date.

F3: The price reflected is the weighted-average sale price for shares sold. The shares were sold in multiple transactions and the range of sale prices for the transactions reported was $14.25 to $14.77 per share. The Reporting Person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

F4: All of the option exercises reported herein were made with respect to options granted pursuant to the Company's 2017 Equity Incentive Plan on July 6, 2017 with vesting schedules generally consisting of 25% cliff vesting on specified dates and with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service through the applicable vesting date.