Timothy Keutzer - 06 Feb 2026 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: 06 Feb 2026
Net transactions value: -$44,019
Form type: 4
Filing time: 09 Feb 2026, 21:09:39 UTC
Previous 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	09 Feb 2026	0001798155

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SPRO	Common Stock	Sale	$44,019	-18,652	-2.5%	$2.36	742,506	06 Feb 2026	Direct	F1

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

Explanation of Responses:

Id	Content
F1	Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of RSUs. The sale occurred automatically to satisfy the tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person.