FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Brady Kelly 2. Date of Event Requiring Statement (Month/Day/Year) 03/02/2026 3. Issuer Name and Ticker or Trading Symbol Seres Therapeutics, Inc. [MCRB] (Last) (First) (Middle) C/O SERES THERAPEUTICS, INC., 101 CAMBRIDGE PARK DRIVE 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) See Remarks 5. If Amendment, Date Original Filed (Month/Day/Year) (Street) CAMBRIDGE, MA 02140 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock 8,441 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	(1)	02/13/2034	Common Stock	2,925	$22	D
Stock Option (right to buy)	(2)	02/06/2035	Common Stock	11,700	$15.64	D
Stock Option (right to buy)	(3)	02/11/2034	Common Stock	2,000	$23	D
Stock Option (right to buy)	(3)	02/11/2034	Common Stock	869	$23	D
Stock Option (right to buy)	(3)	02/11/2034	Common Stock	812	$23	D
Stock Option (right to buy)	(3)	02/11/2034	Common Stock	2,343	$23	D
Stock Option (right to buy)	(4)	02/11/2034	Common Stock	1,430	$23	D
Restricted Stock Units	(5)	(5)	Common Stock	358	$0	D
Restricted Stock Units	(6)	(6)	Common Stock	730	$0	D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Brady Kelly C/O SERES THERAPEUTICS, INC. 101 CAMBRIDGE PARK DRIVE CAMBRIDGE, MA 02140			See Remarks

Signatures

/s/ Thomas J. DesRosier, Attorney-in-Fact for Kelly M. Brady		03/11/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The options were granted on February 14, 2024. The option vested as to 25% of the shares on February 14, 2025. The remainder of the shares will vest in 12 equal quarterly installments thereafter.
(2)	The options were granted on February 7, 2025. The option vested as to 25% of the shares on February 7, 2026. The remainder of the shares will vest in 12 equal quarterly installments thereafter.
(3)	The stock options are fully vested.
(4)	The options were granted on February 12, 2024. The option vested as to 25% of the shares on February 3, 2024. The remainder of the shares will vest in 12 equal quarterly installments thereafter.
(5)	The restricted stock units were granted on February 3, 2023. The restricted stock units vested as to 25% of the shares on February 15, 2024. The remainder of the shares will vest in 12 equal quarterly installments thereafter. The restricted stock units have no expiration date.
(6)	The restricted stock units were granted on February 14, 2024. The restricted stock units vested as to 25% of the shares on February 15, 2025. The remainder of the shares will vest in 12 equal quarterly installments thereafter. The restricted stock units have no expiration date.
Remarks: EVP and Chief Operating Officer Exhibit 24 - Power of Attorney.

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