Tecogen Inc美股招股说明书(2025-05-22版)

This prospectus supplement dated May 22, 2025, supplements, amends and updates certain information included in the reoffer prospectus, and Exchange Commission(“SEC”)on June 23, 2022, as part of the Registration Statement on Form S-8. The reoffer prospectus as supplemented bythis supplement relate to the resale of up to 3,800,000 shares(“shares”)of our common stock, $.001 par value per share(“common stock”), whichmay be reoffered and resold from time to time by certain selling stockholders as described under the caption“Selling Stockholders”in the reofferprospectus as supplemented and amended hereby. The selling stockholders consist of our current or former employees, directors, officers, and consultants who acquired, or will acquire, the deemed to be, our“affiliates”and the shares to be reoffered or resold by the selling stockholders are“control securities”under the Securities Act of1933, as amended(“Securities Act”).You should read this supplement in conjunction with the reoffer prospectus. Each selling stockholder that sells shares pursuant to the reofferprospectus as supplemented hereby and any broker or dealer through whom the shares may be resold may be deemed an “underwriter” within the The common stock offered by the reoffer prospectus as supplemented hereby may be reoffered or resold from time to time in transactionson the NYSE American LLC(“NYSE American”)stock exchange or any other market or exchange on which the shares are quoted or listed, in All of the proceeds of the resale of the shares offered by the reoffer prospectus as supplemented hereby will be received by the sellingstockholders. However, if options are exercised to purchase shares of our common stock covered by the reoffer prospectus as supplemented hereby,we will receive proceeds from payment of the option exercise price which we expect to use for general working capital purposes. The selling Our common stock is currently traded on the NYSE American under the symbol “TGEN.” On May 21, 2025, the closing price of ourcommon stock was $4.36. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these supplement. Any representation to the contrary is a criminal offense.