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

Rhea-AI Filing Summary

On 06/30/2025, Director Michael D. Eisner filed a Form 4 indicating the acquisition of 343 IAC Inc. (ticker: IAC) common share units at $37.34 per share under the company’s Non-Employee Director Deferred Compensation Plan. After the transaction, Eisner’s aggregate beneficial ownership totals 170,711 shares, consisting of 167,349 shares held directly (including those in a grantor trust) and 3,362 share units accrued in the deferred plan. No sales or derivative security transactions were reported, and ownership remains classified as direct. This filing reflects a routine compensation-related share accrual rather than an open-market purchase or a material change in insider positioning.

Insights

Securities Analyst

TL;DR Small, plan-based share accrual; neutral signal, limited market impact.

The Form 4 shows a modest addition of 343 shares by Director Michael Eisner through the company’s deferred compensation program at $37.34 each. Post-transaction holdings rise to 170,711 shares, a negligible percentage of IAC’s outstanding float. Because the acquisition is automatic and compensation-driven—as opposed to a discretionary open-market buy—it offers minimal insight into Eisner’s view of valuation or near-term prospects. The absence of dispositions, options or derivatives suggests no directional change in insider sentiment. Overall, the event is routine, carries no material financial impact, and should not influence valuation models or trading strategies.

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^*

Berenson Stephen

(Last) (First) (Middle)

C/O SERES THERAPEUTICS, INC.

101 CAMBRIDGE PARK DRIVE

(Street)

CAMBRIDGE MA 02140

(City) (State) (Zip)

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)

3. Date of Earliest Transaction (Month/Day/Year)
07/01/2025

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

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

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

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)	$10.71	07/01/2025		A		11,470		(1)	07/01/2035	Common Stock	11,470	$0	11,470	D

Explanation of Responses:

1. The option vests and becomes exercisable in four equal quarterly installments occurring on October 1, 2025, January 1, 2026, April 1, 2026, and July 1, 2026, provided that if the issuer's 2026 annual meeting of stockholders occurs before July 1, 2026, 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	07/02/2025
	** 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.

FAQ

How many IAC shares did Michael D. Eisner acquire according to the Form 4?

343 common share units were acquired on 06/30/2025.

What is Michael Eisner's total IAC share ownership after the reported transaction?

He now beneficially owns 170,711 shares (direct and deferred units combined).

At what price were the new IAC share units credited to Eisner?

The units were recorded at $37.34 per share.

Was the transaction an open-market purchase?

No. The shares were accrued under the Non-Employee Director Deferred Compensation Plan, not bought on the open market.

Did Michael Eisner sell any IAC shares in this filing?

No sales were reported; only an acquisition of share units was disclosed.