Seres Therapeutics grants 6,500 stock options to director

Seres Therapeutics, Inc. director Eric D. Shaff received a grant of stock options covering 6,500 shares of common stock.

Rhea-AI Filing Summary

Seres Therapeutics, Inc. director Eric D. Shaff received a grant of stock options covering 6,500 shares of common stock. The options have an exercise price of $7.14 per share and expire on July 7, 2036. Vesting occurs on the earlier of July 8, 2027 or the day immediately prior to the first annual meeting of stockholders occurring after July 8, 2026.

Insights

Equity compensation analyst

Director received a standard-sized stock option grant with time-based vesting.

Director Eric D. Shaff was granted options on 6,500 shares of common stock at an exercise price of $7.14 per share, expiring on July 7, 2036. This is classified as a grant or award acquisition rather than an open-market purchase.

The options vest in a single tranche on the earlier of July 8, 2027 or the day before the first annual stockholder meeting after July 8, 2026. This time-based vesting aligns the director’s incentives with longer-term company performance and board service, without indicating any discretionary market buying or selling.

Insider Trade Summary

Grant/Award: 6,500 shares

Grant/Award 1 txn

Insider Shaff Eric D.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy) F1	6,500	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 6,500 contracts (Direct)

Footnotes (1)

1. F1. The option vests and becomes exercisable on the earlier to occur of (i) July 8, 2027 or (ii) the day immediately prior to the first annual meeting of the Company's stockholders occurring after July 8, 2026.

Key Figures

Option shares granted: 6,500 shares Exercise price: $7.14 per share Expiration date: July 7, 2036 +2 more

5 metrics

Option shares granted 6,500 shares Stock Option (right to buy) grant to director on July 8, 2026

Exercise price $7.14 per share Conversion or exercise price of the stock option grant

Expiration date July 7, 2036 Expiration of the granted stock options

Shares underlying options 6,500 shares Common Stock underlying the derivative security

Total options held after grant 6,500 options Total derivative securities following the reported transaction

Key Terms

Stock Option (right to buy), Grant, award, or other acquisition, underlying security, vests and becomes exercisable

4 terms

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

Grant, award, or other acquisition financial

"transaction_code_description: Grant, award, or other acquisition"

underlying security financial

"underlying_security_title: Common Stock as the underlying security"

vests and becomes exercisable financial

"The option vests and becomes exercisable on the earlier to occur of"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Eric D. Shaff report on his Form 4 for MCRB?

Eric D. Shaff reported a grant of stock options for 6,500 shares of Seres Therapeutics common stock, with an exercise price of $7.14 per share and expiration on July 7, 2036.

Is the Form 4 transaction for MCRB an insider buy or option grant?

The Form 4 for MCRB reports an option grant, coded "A" as a grant, award, or other acquisition, rather than an open-market stock purchase or sale.

How many shares are covered by Eric D. Shaff’s stock options in MCRB?

The stock option award to Eric D. Shaff covers 6,500 shares of Seres Therapeutics common stock as the underlying security, all from a single grant transaction.

What is the exercise price and term of the MCRB option grant?

The granted options have an exercise price of $7.14 per share and an expiration date of July 7, 2036, providing roughly a decade-long window to exercise after vesting.

When do Eric D. Shaff’s MCRB options vest?

The options vest and become exercisable on the earlier of July 8, 2027 or the day immediately prior to the first annual stockholders’ meeting occurring after July 8, 2026.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 07/10/2026 - 04:15 PM EDT 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^*

Shaff Eric D.

(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)

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

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)	$7.14	07/08/2026		A		6,500		(1)	07/07/2036	Common Stock	6,500	$0	6,500	D

Explanation of Responses:

1. The option vests and becomes exercisable on the earlier to occur of (i) July 8, 2027 or (ii) the day immediately prior to the first annual meeting of the Company's stockholders occurring after July 8, 2026.

	/s/ Thomas J. DesRosier, Attorney-in-Fact	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)