Sec Form 4 Filing - Ege David S. @ Seres Therapeutics, Inc. - 2023-04-27

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

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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Ege David S. 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 (Last) (First) (Middle) C/O SERES THERAPEUTICS, INC., 200 SIDNEY STREET 3. Date of Earliest Transaction (MM/DD/YY) 04/27/2023 (Street) CAMBRIDGE, MA02139 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 Common stock 04/27/2023 A( 1 ) 20,000 A $ 0 66,734 D Common stock 04/28/2023 S( 2 ) 7,038 D $ 5.19 ( 3 ) 59,696 D

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 of Derivative Security: 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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Ege David S. C/O SERES THERAPEUTICS, INC. 200 SIDNEY STREET CAMBRIDGE, MA02139 See Remarks Signatures /s/ Thomas J. DesRosier, attorney-in-fact for David S. Ege 05/01/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On May 3, 2021, the reporting person was granted an award of 40,000 restricted stock units, which vested in the form of shares of the Issuer's common stock in two equal installments upon the satisfaction of certain performance criteria. On April 27, 2023, the Issuer's Board of Directors determined that the performance criteria for the second installment were met, resulting in the vesting and settlement of the award as to 20,000 shares. ( 2 )The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 instruction adopted by the reporting person on May 3, 2021, solely with the intent to cover taxes in connection with the vesting of the restricted stock units. ( 3 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $5.0350 to $5.1900, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Remarks: Executive Vice President and Chief Technology Officer

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.