Timothy Keutzer - 28 Aug 2025 Form 4 Insider Report for Spero Therapeutics, Inc. (SPRO)

Role: Chief Operating Officer
Signature: /s/ Maegan Deare, Attorney-in-Fact for Timothy Keutzer
Issuer symbol: SPRO
Transactions as of: 28 Aug 2025
Net transactions value: -$3,339
Form type: 4
Filing time: 03 Sep 2025, 06:02:55 UTC
Previous filing: 05 Feb 2025
Next filing: 05 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Keutzer Timothy	Chief Operating Officer	C/O SPERO THERAPEUTICS, INC., 675 MASSACHUSETTS AVENUE, 14TH FLOOR, CAMBRIDGE	/s/ Maegan Deare, Attorney-in-Fact for Timothy Keutzer	02 Sep 2025	0001798155

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SPRO	Common Stock	Sale	$3,339	-1,695	-0.23%	$1.97	739,744	28 Aug 2025	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The reported transaction is a sale of common stock effected to cover tax withholding obligations pursuant to a "sell to cover" provision included in each RSU Agreement in connection with the vesting of restricted stock units ("RSUs") that were granted to the Reporting Person on August 26, 2021.