ClearSign Technologies Corporation (NASDAQ:CLIR) ("ClearSign" or the "Company"), a leader in advanced combustion and sensing technologies that help industrial operators dramatically reduce emissions, increase efficiency and support the use of cleaner fuels including hydrogen, today announces the pricing of an underwritten public offering with primarily existing stockholders of 777,780 shares of its common stock (the "Public Offering") at a price to the public of $4.33 per share, for gross proceeds of $3,367,787. The Company has also granted to the underwriter a 30-day option to purchase, at the same price per share as the underwriter paid for the initial shares, up to an additional 15% of the shares of common stock offered in the Public Offering to cover over-allotments in connection with the Public Offering, which if exercised in full would increase the gross proceeds to $3,872,955.51.

The Public Offering is expected to close on or about June 1, 2026, subject to customary closing conditions.

ClearSign intends to use the net proceeds from the Public Offering for working capital, research and development, marketing and sales, and general corporate purposes.