Offerings // TECOGEN INC.

TGEN offering history

Every offering-related filing in TECOGEN INC.’s recent SEC record — registrations (announced capacity) kept separate from pricing documents (executed sales). Reviewed 688 filings back to Dec 22, 2011.

Last executed offering

Jul 21, 2025

424B4 — priced deal (shares or notes)

Last registration (announced)

Aug 31, 2026

S-1/A — capacity, not a sale

Executed, last 12 months

424B pricings + 8-K 3.02 sales

Registered, last 12 months

S-1/S-3/F-series registrations

Date	Filing		What it means
Sep 4, 2026	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Sep 3, 2026	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Sep 1, 2026	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Aug 31, 2026	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Aug 31, 2026	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Jul 21, 2025	424B4 →	EXECUTED	Final prospectus — offering priced (typical for IPOs and marketed share deals)
Jul 17, 2025	S-1MEF →	REGISTERED	S-1MEF registration — capacity to sell shares, not a sale yet
Jul 17, 2025	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jul 16, 2025	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Jul 16, 2025	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Jul 16, 2025	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Jul 15, 2025	S-1 →	REGISTERED	S-1 registration — capacity to sell shares, not a sale yet
May 22, 2025	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
May 22, 2025	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Jul 1, 2022	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Mar 23, 2021	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Mar 22, 2021	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jul 27, 2020	AW →	WITHDRAWN	Registration withdrawn
Jul 10, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jul 10, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Apr 23, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Apr 6, 2020	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Apr 6, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Apr 3, 2020	RW →	WITHDRAWN	Registration withdrawn
Apr 2, 2020	S-3/A →	REGISTERED	S-3/A registration — capacity to sell shares, not a sale yet
Apr 27, 2017	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Apr 12, 2017	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jul 18, 2016	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jul 7, 2016	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Jun 30, 2016	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Apr 15, 2016	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Dec 31, 2015	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Oct 5, 2015	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Sep 30, 2015	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Sep 29, 2015	S-3/A →	REGISTERED	S-3/A registration — capacity to sell shares, not a sale yet
Sep 23, 2015	S-3/A →	REGISTERED	S-3/A registration — capacity to sell shares, not a sale yet
Sep 1, 2015	S-3/A →	REGISTERED	S-3/A registration — capacity to sell shares, not a sale yet
Aug 6, 2015	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Jun 22, 2015	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Jan 30, 2015	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)

TGEN offering-related filings from SEC EDGAR, newest first (capped at 40). Each links to the original document.

Two honest limits. (1) A 424B takedown can price shares or notes — EDGAR’s metadata doesn’t say which, so open the document: large investment-grade filers use these mostly for bond deals (no dilution), small-caps mostly for shares. (2) At-the-market (ATM) programs sell shares gradually and individual sales are not separately filed — the visible footprint is the enabling shelf and its 424B5; actual ATM share counts surface later in the 10-Q/10-K share count. Educational information from public filings, not investment advice.

Is a shelf active now? →Do they need money? →Red flags →Full TGEN workspace →

TGEN offering FAQ

When did TGEN last execute an offering?

Per SEC filings, TECOGEN INC.'s most recent priced offering document is a 424B4 filed 2025-07-21. Note a 424B takedown can price shares or notes (debt) — the linked document says which.

When did TGEN last announce or register an offering?

The most recent registration is a S-1/A filed 2026-08-31. A registration is capacity to sell shares — not a sale.

Does an offering always mean dilution?

Registered direct offerings and shelf takedowns issue new shares and dilute existing holders. Resale registrations (424B3/B7) let existing holders sell and do not create new shares. Secondary sales by insiders also do not dilute. Each row here is labeled with what it is.

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