Esther Rajavelu - 07 Nov 2025 Form 4 Insider Report for Spero Therapeutics, Inc. (SPRO)

Role: Chief Executive Officer, Chief Financial Officer and Chief Business Officer
Signature: /s/ Maegan Deare, Attorney-in-Fact for Esther Rajavelu
Issuer symbol: SPRO
Transactions as of: 07 Nov 2025
Net transactions value: -$95,440
Form type: 4
Filing time: 12 Nov 2025, 20:44:50 UTC
Previous filing: 06 May 2025
Next filing: 04 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Rajavelu Esther	Chief Executive Officer, Chief Financial Officer and Chief Business Officer	C/O SPERO THERAPEUTICS, INC., 675 MASSACHUSETTS AVENUE, 14TH FLOOR, CAMBRIDGE	/s/ Maegan Deare, Attorney-in-Fact for Esther Rajavelu	12 Nov 2025	0001903716

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	SPRO	Common Stock	Sale	$95,440	-40,270	-4.4%	$2.37	869,450	07 Nov 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 November 13, 2023.

Remarks:

Chief Executive Officer, Chief Financial Officer and Chief Business Officer