Seres Therapeutics director gets 7,508 stock options

Seres Therapeutics director Dennis A. Ausiello received a grant of stock options covering 7,508 shares of common stock.

Rhea-AI Filing Summary

Seres Therapeutics director Dennis A. Ausiello received a grant of stock options covering 7,508 shares of common stock. The options have an exercise price of $7.94 per share and expire on July 1, 2036. The award vests in four equal quarterly installments on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, with the final installment vesting earlier if the 2027 annual stockholder meeting occurs before July 1, 2027. Vesting requires his continued service on the board as a non-employee director through each vesting date.

Insider Trade Summary

Grant/Award: 7,508 shares

Grant/Award 1 txn

Insider Ausiello Dennis A

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	7,508	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy) — 7,508 contracts (Direct)

Footnotes (1)

1. F1. The option vests and becomes exercisable in four equal quarterly installments occurring on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, provided that if the issuer's 2027 annual meeting of stockholders occurs before July 1, 2027, 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.

Key Figures

Option grant size: 7,508 options Exercise price: $7.94 per share Expiration date: July 1, 2036 +1 more

4 metrics

Option grant size 7,508 options Stock Option (right to buy) granted to director

Exercise price $7.94 per share Conversion or exercise price of granted options

Expiration date July 1, 2036 Option term end for this grant

Post-transaction derivative holdings 7,508 options Total derivative securities following this grant

Key Terms

Stock Option (right to buy), exercise price, vesting, non-employee director, +1 more

5 terms

Stock Option (right to buy) financial

"security_title: Stock Option (right to buy)"

exercise price financial

"conversion_or_exercise_price: 7.9400"

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.

vesting financial

"The option vests and becomes exercisable in four equal quarterly installments"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

non-employee director financial

"continuing in service on the Board as a non-employee director"

annual meeting of stockholders financial

"if the issuer's 2027 annual meeting of stockholders occurs before July 1, 2027"

FAQ

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

What did Seres Therapeutics (MCRB) director Dennis A. Ausiello receive in this Form 4?

Dennis A. Ausiello received a grant of stock options for 7,508 shares of Seres Therapeutics common stock. These are compensation-related options, not an open-market purchase or sale of existing shares.

What is the exercise price and expiration date of Dennis Ausiello’s Seres Therapeutics options?

The granted stock options have an exercise price of $7.94 per share and expire on July 1, 2036. This means he can choose to buy shares at $7.94 any time after vesting until that expiration date.

How do Dennis Ausiello’s Seres Therapeutics options vest according to the Form 4?

The options vest in four equal quarterly installments on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027. If the 2027 annual stockholder meeting occurs earlier, the final installment vests immediately before that meeting.

What service conditions apply to Dennis Ausiello’s MCRB stock option grant?

Each vesting installment is conditioned on Dennis Ausiello continuing to serve on the Seres Therapeutics board as a non-employee director through the relevant vesting date. If service ends earlier, unvested installments would not vest under these terms.

How many Seres Therapeutics derivative securities does Dennis Ausiello hold after this grant?

Following this transaction, Dennis Ausiello holds 7,508 stock options as reported in the filing. These options represent rights to acquire 7,508 shares of Seres Therapeutics common stock upon exercise after they vest.

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

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Accepted by SEC EDGAR 07/02/2026 - 06:05 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^*

Ausiello Dennis A

(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)
07/01/2026

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)	$7.94	07/01/2026		A		7,508		(1)	07/01/2036	Common Stock	7,508	$0	7,508	D

Explanation of Responses:

1. The option vests and becomes exercisable in four equal quarterly installments occurring on October 1, 2026, January 1, 2027, April 1, 2027, and July 1, 2027, provided that if the issuer's 2027 annual meeting of stockholders occurs before July 1, 2027, 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.

	/s/ Thomas J. DesRosier, Attorney-in-Fact	07/02/2026
	** 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)