Robert L. Rosiello - 05 Aug 2025 Form 4 Insider Report for Seres Therapeutics, Inc. (MCRB)

Role: Director
Signature: /s/ Thomas J. DesRosier, Attorney-in-Fact for Robert L. Rosiello
Issuer symbol: MCRB
Transactions as of: 05 Aug 2025
Net transactions value: $0
Form type: 4
Filing time: 06 Aug 2025, 16:10:04 UTC
Previous filing: 09 Jun 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Rosiello Robert L.	Director	C/O SERES THERAPEUTICS, INC., 101 CAMBRIDGE PARK DRIVE, CAMBRIDGE	/s/ Thomas J. DesRosier, Attorney-in-Fact for Robert L. Rosiello	06 Aug 2025	0001645041

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	+10,000		$0.000000	10,000	05 Aug 2025	Common Stock	10,000	$14.28	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 August 5, 2026, August 5, 2027, August 5, 2028, August 5, 2029, subject to the reporting person continuing in service on the Board as a non-employee director through the applicable vesting date.