Dennis A. Ausiello - Jul 1, 2025 Form 4 Insider Report for Seres Therapeutics, Inc. (MCRB)

Role: Director
Signature: /s/ Thomas J. DesRosier, Attorney-in-Fact
Stock symbol: MCRB
Transactions as of: Jul 1, 2025
Transactions value $: $0
Form type: 4
Date filed: 7/2/2025, 05:58 PM
Previous filing: May 30, 2025
Next filing: Aug 15, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Ausiello Dennis A	Director	C/O SERES THERAPEUTICS, INC., 101 CAMBRIDGE PARK DRIVE, CAMBRIDGE	/s/ Thomas J. DesRosier, Attorney-in-Fact	2025-07-02	0001381994

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	MCRB	Stock Option (right to buy)	Award	$0	+6.45K		$0.00	6.45K	Jul 1, 2025	Common Stock	6.45K	$10.71	Direct	F1

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

Explanation of Responses:

Id	Content
F1	The option vests and becomes exercisable in four equal quarterly installments occurring on October 1, 2025, January 1, 2026, April 1, 2026, and July 1, 2026, provided that if the issuer's 2026 annual meeting of stockholders occurs before July 1, 2026, the final quarterly vesting installment will vest on the day immediately prior to the date of such annual meeting, in each case, subject to the reporting person continuing in service on the Board as a non-employee director through the applicable vesting date.

Content

The option vests and becomes exercisable in four equal quarterly installments occurring on October 1, 2025, January 1, 2026, April 1, 2026, and July 1, 2026, provided that if the issuer's 2026 annual meeting of stockholders occurs before July 1, 2026, the final quarterly vesting installment will vest on the day immediately prior to the date of such annual meeting, in each case, subject to the reporting person continuing in service on the Board as a non-employee director through the applicable vesting date.