ClearSign Technologies Corporation Provides Fourth Quarter and Full Year 2025 Update (Form 8-K)

ClearSign Technologies Corporation Provides Fourth Quarter and Full Year 2025 Update

Achieves Record Quarterly Revenue of $3.7 Million

Annual Revenue Up 44% to Record $5.2 Million

TULSA, Okla., April 9, 2026 - 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 safety, and support the use of cleaner fuels including hydrogen, today provides an update on operations for the fourth quarter and full year ended December 31, 2025.

"We're pleased to have closed the year on a high note, delivering record results for both the fourth quarter and the full year. We believe that this performance reflects ClearSign's growing recognition across the industry and increasing traction in our markets," said Jim Deller, Ph.D., Chief Executive Officer of ClearSign. "We expect this momentum to continue, supported by a strong and expanding proposal pipeline. Our highly adaptable, new flexible fuel ClearSign Core-2 process burner technology, which delivers ultra-low emissions while utilizing fuel blends, including up to 100% hydrogen, enables us to provide combustion solutions for a broader range of customer applications. These innovations have already led to an increase in our backlog of orders, which now includes projects for new heater configurations that we previously would not have been able to address."

"We anticipate that these, and other ongoing projects, when completed and operational will strengthen our track record and expand our base of references. Looking ahead, our priorities are clear: continue to grow our proposal pipeline and convert those opportunities into orders," concluded Dr. Deller.

Strategic and Operational Highlights

Recent strategic and operational highlights including, and subsequent to, the fourth quarter of 2025:

Received Engineering Orders for 36 Process Burner Heaters and 32 Burner Process Heaters: The Company received two separate orders: (1) the first order was from an integrated petroleum producer as the first phase of a process heater retrofit for a total of 36 ClearSign Core^™ burners to be installed in their U.S. Gulf Coast refinery, and (2) the second order was from a major refiner as the first phase of a process heater retrofit for a total of 32 ClearSign Core^™ burners to be installed in one of its California refineries.

Reported Successful Sub 5ppm Department of Energy/Small Business Innovation Research Flexible Fuel Burner Testing: In conjunction with the U.S. Department of Energy's ("DOE") National Energy Technology Laboratory ("NETL"), under its Small Business Innovation Research ("SBIR") program, the Company successfully completed the testing of its ClearSign Core^™ Flexible Fuel, 100% Hydrogen Capable process burner branded as ClearSign Core^™ 2.

Received Fifth Low-Emission Flare Order from an Energy Company in California: The Company received an order covering engineering and product delivery for a total retrofit enclosed flare system at a production facility in California's San Joaquin Valley, scheduled for delivery in the third quarter of 2026. The scope of the order includes upgraded flare technology, stack components, and control upgrades, further expanding ClearSign's engagement beyond burner technology and into broader emission and system integration solutions.

Received Order for Comprehensive Testing of 100% Hydrogen Capable Burner from Petrochemical Client Requesting Performance Mapping for Future Deployment: The Company received an order for a comprehensive range of process burner testing from a major petrochemical customer. The testing included the collection of comprehensive operational data over a range of operating conditions and fuel blends.

Received Two Separate ClearSign Core^TM "M" Series Burner Orders from Heater Manufacturer Devco Process Heaters: Both orders are for the new ClearSign Core^™ M25. One of these orders has shipped and is awaiting installation in a hot oil heater at a New Mexico gas processing facility and the other has been installed and successfully started up in a gas processing facility of a multinational energy company in West Texas.

Financial Information

Cash and cash equivalents were approximately $9.2 million as of December 31, 2025.

There were 5,328,730 shares of the Company's common stock issued and outstanding as of December 31, 2025, which reflects the 1-for-10 reverse stock split of our shares of common stock that became effective on March 16, 2026.

Conference Call

The Company will be hosting a call at 5:00 PM ET today. Investors interested in participating on the live call can dial 1-888-506-0062 within the U.S. or 1-973-528-0011 from abroad, both using Participant Access Code: 837062. Investors can also access the call online through a listen-only webcast at https://www.webcaster5.com/Webcast/Page/3133/53796 or on the investor relations section of the Company's website at http://ir.clearsign.com/overview.

The Company will host a Q&A session during the call and investors wishing to submit a question ahead of time can do so by emailing questions to [email protected].

The webcast will be archived on the Company's investor relations website for at least 90 days and a telephonic playback of the conference call will be available by calling 877-481-4010 within the U.S. or 919-882-2331 from abroad using Replay Passcode #53796. The telephonic playback will be available for 7 days after the conference call.

About ClearSign Technologies Corporation

ClearSign Technologies Corporation designs and develops products and technologies for the purpose of decarbonization and improving key performance characteristics of industrial and commercial systems, including operational performance, energy efficiency, emission reduction, safety, the use of hydrogen as a fuel and overall cost-effectiveness. Our patented technologies, embedded in established OEM products as ClearSign Core^™ and ClearSign Eye^™ and other sensing configurations, enhance the performance of combustion systems and fuel safety systems in a broad range of markets, including the energy (upstream oil production and down-stream refining), commercial/industrial boiler, chemical, petrochemical, transport and power industries. For more information, please visit www.clearsign.com.