Seres Therapeutics (MCRB) awards 7,500 stock options to officer DesRosier with long vesting

Rhea-AI Filing Summary

Seres Therapeutics, Inc. reported that officer Thomas DesRosier received a grant of stock options covering 7,500 shares of common stock at an exercise price of $9.13 per share. The options expire on March 3, 2036. According to the vesting schedule, 25% of the shares vest on March 2, 2027, with the remaining shares vesting in 12 equal quarterly installments thereafter.

Insights

Equity compensation analyst

Officer receives 7,500-stock-option grant with long-term vesting.

Officer Thomas DesRosier was granted stock options on July 8, 2026 for 7,500 shares of common stock at an exercise price of $9.13 per share. This is recorded as a grant or award acquisition, not an open-market purchase.

The options vest over time: 25 percent on March 2, 2027, and the remaining 75 percent in 12 equal quarterly installments thereafter, with expiration on March 3, 2036. Such time-based vesting is designed to encourage longer-term service and alignment with shareholders, while spreading the economic benefit over several years.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider DesRosier Thomas

Role See Remarks

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy)	7,500	$0.00	--

Holdings After Transaction: Stock Option (right to buy) — 7,500 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Option grant size: 7,500 shares Exercise price: $9.13 per share Post-grant derivative holdings from award: 7,500 options +3 more

6 metrics

Option grant size 7,500 shares Number of common shares underlying the stock option grant to Thomas DesRosier

Exercise price $9.13 per share Exercise price of the stock options granted to Thomas DesRosier

Post-grant derivative holdings from award 7,500 options Total options held from this grant following the transaction

Initial vesting date March 2, 2027 Date on which 25% of the option shares vest

Vesting installments 12 quarterly installments Schedule over which the remaining 75% of option shares vest

Option expiration March 3, 2036 Expiration date of the granted stock options

Key Terms

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

4 terms

Stock Option (right to buy) financial

"The reported security is described as "Stock Option (right to buy)"."

exercise price financial

"The options have an exercise price of $9.13 per share."

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 thereafter."

expiration date financial

"The options carry an expiration date of March 3, 2036."

The expiration date is the deadline after which a financial contract, such as an option or a futures agreement, is no longer valid or can be exercised. It matters to investors because it determines the timeframe during which they can take action or benefit from the contract, similar to how a coupon or a food item has a limited period of usefulness. Once the expiration date passes, the contract loses its value or ability to be used.

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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

FAQ

What did Seres Therapeutics (MCRB) report for Thomas DesRosier in this Form 4?

The filing reports that officer Thomas DesRosier received a grant of 7,500 stock options for Seres Therapeutics common stock, recorded as a grant or award acquisition rather than an open-market trade.

What is the exercise price of the stock options granted to Thomas DesRosier at Seres Therapeutics (MCRB)?

The stock options granted to Thomas DesRosier have an exercise price of $9.13 per share. This is the price he must pay per share to exercise the options, subject to vesting.

How many Seres Therapeutics (MCRB) shares are covered by the new option grant?

The option grant to Thomas DesRosier covers 7,500 shares of Seres Therapeutics common stock. Following the grant, his reported derivative holdings from this award total 7,500 options.

What is the vesting schedule for Thomas DesRosier’s Seres Therapeutics (MCRB) stock options?

According to the footnote, 25% of the options vest on March 2, 2027. The remaining shares vest in 12 equal quarterly installments thereafter, creating a multi-year vesting period.

When do Thomas DesRosier’s Seres Therapeutics (MCRB) stock options expire?

The stock options granted to Thomas DesRosier are scheduled to expire on March 3, 2036. After that date, any unexercised options from this grant will no longer be exercisable.

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^*

DesRosier Thomas

(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		7,500		(1)	03/03/2036	Common Stock	7,500	$0	7,500	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:

EVP and Chief Legal Officer

	/s/ Thomas J. DesRosier	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)