Sec Form 4 Filing - PANORA ROBERT A @ TECOGEN INC. - 2025-05-27

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

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1. Name and Address of Reporting Person PANORA ROBERT A 2. Issuer Name and Ticker or Trading Symbol TECOGEN INC. [ TGEN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) COO and President (Last) (First) (Middle) C/O TECOGEN, INC., 76 TREBLE COVE ROAD, BLDG 1 3. Date of Earliest Transaction (MM/DD/YY) 05/27/2025 (Street) N. BILLERICA, MA01862 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

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 Stock Option (Right to Buy) $ 0.71 05/27/2025 X 70,000 ( 1 ) 07/09/2030 Common Stock 70,000 $ 0.71 130,000 ( 2 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other PANORA ROBERT A C/O TECOGEN, INC. 76 TREBLE COVE ROAD, BLDG 1 N. BILLERICA, MA01862 COO and President Signatures /s/ Robert A. Panora 06/02/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )100,000 shares of the 200,000 options shares granted pursuant to Stock Option Agreement dated 7/9/2020 vested on 6/30/2022 upon achievement of Adjusted EBITDA performance milestone. ( 2 )Exercise of option to purchase 70,000 shares of the 100,000 vested shares pursuant to Stock Option Agreement dated 7/9/2020 for 200,000 option shares leaves vested options to purchase 30,000 shares and unvested options to purchase 100,000 shares.

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).

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