Tecogen Inc. Files S-3 Registration; Trusts Enter 182-Day Lock-Up

What Happened

• On August 31, 2026, Tecogen Inc. filed a Form 8-K to disclose that it concurrently submitted a Registration Statement on Form S-3 with the SEC to register the reoffer and resale of 4,507,603 shares of its common stock by certain selling stockholders. The shares were previously acquired in private placements.
• On the same day, the trustee of the Hatsopoulos 2012 Family Trust and The George N. Hatsopoulos GST non-exempt QTIP Marital Trust (the “Trusts”), holding 3,475,714 of those shares, entered into lock-up agreements with Tecogen restricting transfers of those shares for 182 calendar days from the date the SEC declares the registration statement effective.

Key Details

• Total shares covered by the registration: 4,507,603 common shares (par value $0.001).
• Shares subject to lock-up: 3,475,714 held by the two Hatsopoulos trusts.
• Lock-up duration: 182 calendar days from the SEC’s declaration of effectiveness of the S-3.
• Shares were acquired in private placement transactions; the filing registers them for resale (not a new issuance). Lock-up form filed as Exhibit 99.1.

Why It Matters

• This filing could increase the number of freely tradable Tecogen shares once the S-3 is declared effective, which may affect supply and trading liquidity.
• The 182-day lock-up on the large Trust holdings limits immediate sales by those holders, partially constraining near-term dilution or selling pressure from that block.
• No offers or sales by the selling stockholders may occur until the registration is declared effective by the SEC. This is a disclosure about resale mechanics and investor liquidity, not an operational or management change.