[Form 4] Seres Therapeutics, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Seres Therapeutics, Inc. reported that officer Brady Kelly received a grant of stock options covering 18,750 shares of common stock at an exercise price of $9.13 per share. The options expire on March 3, 2036, with 25% vesting on March 2, 2027 and the remaining 75% vesting in 12 equal quarterly installments thereafter.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Brady Kelly

Role See Remarks

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	18,750	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 18,750 shares (Direct)

Footnotes (1)

1. [object Object]

Key Figures

Option grant size: 18,750 shares Exercise price: $9.13 per share Post-transaction derivative holdings: 18,750 options +3 more

6 metrics

Option grant size 18,750 shares Stock option covering 18,750 shares of common stock granted to officer Brady Kelly

Exercise price $9.13 per share Exercise price of the stock option granted on the reported date

Post-transaction derivative holdings 18,750 options Total stock options held following the reported grant transaction

Initial vesting portion 25% of shares Portion of the option vesting on March 2, 2027

Subsequent vesting schedule 12 equal quarterly installments Remaining shares vest in 12 equal quarterly installments after March 2, 2027

Option expiration date March 3, 2036 Expiration date of the stock option granted to Brady Kelly

Key Terms

Stock Option (right to buy), exercise price, vest in 12 equal quarterly installments

3 terms

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

exercise price financial

"conversion_or_exercise_price: 9.1300"

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

vest in 12 equal quarterly installments financial

"The remainder of the shares will vest in 12 equal quarterly installments"

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/10/2026 - 04:15 PM Accepted by SEC EDGAR 07/10/2026 - 04:15 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Brady Kelly

(Last) (First) (Middle)

C/O SERES THERAPEUTICS, INC.

101 CAMBRIDGE PARK DRIVE

(Street)

CAMBRIDGE MASSACHUSETTS 02140

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Seres Therapeutics, Inc. [ MCRB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	See Remarks

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/08/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$9.13	07/08/2026		A		18,750		(1)	03/03/2036	Common Stock	18,750	$0	18,750	D

Explanation of Responses:

1. The option will vest as to 25% of the shares on March 2, 2027. The remainder of the shares will vest in 12 equal quarterly installments thereafter.

Remarks:

Chief Operating Officer, EVP

	/s/ Thomas J. DesRosier, Attorney-in-Fact for Kelly M. Brady	07/10/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)