TGEN Filing: Joint Tenants Report 460,300 Shares Representing 1.8%

Rhea-AI Filing Summary

Tecogen Inc. Schedule 13G/A: Tryfon Natsis and Despoina Pantopoulou report joint beneficial ownership of 460,300 shares of Tecogen common stock, representing 1.8% of the class based on 25,269,362 shares outstanding as of May 20, 2025. The reporting persons hold shared voting and dispositive power over all 460,300 shares and have no sole voting or dispositive power. Each reporting person is a citizen of Greece and lists a residence in Abu Dhabi. The filing includes a certification that the shares were not acquired to change or influence control of the issuer.

Positive

• Regulatory transparency: The reporting persons filed a Schedule 13G/A disclosing beneficial ownership as required.
• Non-controlling stake: Ownership of 1.8% is below 5%, indicating no reported intent to influence control.
• Clear power allocation: Filing specifies shared voting and dispositive power for all reported shares.

Negative

• None.

Insights

Financial Analyst

TL;DR A disclosed 1.8% stake is material for transparency but not a control position; no purchase timing or cost information is provided.

The filing documents a small, non-controlling joint stake of 460,300 shares in Tecogen, representing 1.8% of outstanding common stock based on the prospectus share count. Because the reporting persons report only shared voting and dispositive power and explicitly certify the holdings are not intended to influence control, this disclosure appears routine and primarily serves regulatory transparency. The filing does not disclose acquisition dates, price paid, or any plans regarding future transactions, limiting analysis of intent or economic exposure.

Corporate Governance Expert

TL;DR Filing shows compliant disclosure by joint holders with shared control; holding size is below thresholds that typically trigger control concerns.

The joint tenants have properly reported beneficial ownership under Schedule 13G/A. At 1.8% ownership, the stake is below 5%, consistent with the document's statement that the position constitutes ownership of 5 percent or less of a class. The certification clarifies the absence of intent to influence issuer control. There is no indication of group formation, agreements, or plans that would alter governance dynamics based on the information provided.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Tecogen Inc.

(Name of Issuer)

Common Stock, $0.001 par value

(Title of Class of Securities)

87876P201

(CUSIP Number)

06/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 87876P201

1

Names of Reporting Persons

Tryfon Natsis and Depoina Pantopoulou, as Joint Tenants with the Right of Survivorship

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

GREECE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 460,300.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 460,300.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

460,300.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.8 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: Percent of class represented by amount in row (9) has been calculated based on 25,269,362 shares of Tecogen Inc. common stock outstanding as of May 20, 2025, as reported in Tecogen Inc.'s prospectus on Form 424B3 filed with the Securities and Exchange Commission on May 22, 2025.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Tecogen Inc.
(b)	Address of issuer's principal executive offices: 76 Treble Cove Road, Building 1, North Billerica, Massachusetts, 01862
Item 2.
(a)	Name of person filing: This statement is being filed by Tryfon Natsis and Despoina Pantopoulou, as spouses and Joint Tenants with the Right of Survivorship, as Reporting Persons.
(b)	Address or principal business office or, if none, residence: The residential address for each Reporting Person is Block 7, The St. Regis Saadiyat Island Residences, Al Saadiyat Island, 54345 Abu Dhabi, United Arab Emirates.
(c)	Citizenship: Each Reporting Person is a citizen of Greece.
(d)	Title of class of securities: Common Stock, $0.001 par value
(e)	CUSIP No.: 87876P201
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 460,300 shares of Tecogen Inc. common stock.
(b)	Percent of class: 1.8% (based on 25,269,362 shares of Tecogen Inc. common stock outstanding as of May 20, 2025, as reported in Tecogen Inc.'s prospectus on Form 424B3 filed with the Securities and Exchange Commission on May 22, 2025).
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 460,300
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 460,300
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Tryfon Natsis and Depoina Pantopoulou, as Joint Tenants with the Right of Survivorship

Signature:	/s/ Tryfon Natsis
Name/Title:	Tryfon Natsis, in his capacity as a Joint Tenant with the Right of Survivorship
Date:	08/14/2025

Signature:	/s/ Despoina Pantopoulou
Name/Title:	Despoina Pantopoulou, in her capacity as a Joint Tenant with the Right of Survivorship
Date:	08/14/2025

FAQ

How many Tecogen (TGEN) shares do Tryfon Natsis and Despoina Pantopoulou own?

They report beneficial ownership of 460,300 shares of Tecogen common stock.

What percentage of Tecogen does the 460,300 shares represent?

The filing states this equals 1.8% of Tecogen's common stock based on 25,269,362 shares outstanding as of May 20, 2025.

Do the reporting persons have sole voting or dispositive power over the shares?

No. The filing indicates 0 shares with sole voting or dispositive power and 460,300 shares with shared voting and dispositive power.

Did the filers state an intent to influence control of Tecogen?

No. The certification states the securities were not acquired and are not held to change or influence control of the issuer.

What is the residence and citizenship of the reporting persons?

Each reporting person is a citizen of Greece and lists a residential address in Abu Dhabi, United Arab Emirates.