# EDGAR Filing Document

**Accession Number:** 0001434524
**File Stem:** 0001558370-25-008620
**Filing Date:** 2025-6
**Character Count:** 161598
**Document Hash:** e195b21dddf65f593b61b65d5b4cf6af
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001558370-25-008620.hdr.sgml**: 20250613

**ACCESSION NUMBER**: 0001558370-25-008620

**CONFORMED SUBMISSION TYPE**: ARS

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20241231

**FILED AS OF DATE**: 20250613

**DATE AS OF CHANGE**: 20250613

**EFFECTIVENESS DATE**: 20250613

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ClearSign Technologies Corp
- **CENTRAL INDEX KEY:** 0001434524
- **STANDARD INDUSTRIAL CLASSIFICATION:** INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
- **ORGANIZATION NAME:** 08 Industrial Applications and Services
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** ARS
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-35521
- **FILM NUMBER:** 251046743

**BUSINESS ADDRESS:**
- **STREET 1:** 8023 E. 63RD PLACE, SUITE 101
- **CITY:** TULSA
- **STATE:** OK
- **ZIP:** 74133
- **BUSINESS PHONE:** (918) 236-6461

**MAIL ADDRESS:**
- **STREET 1:** 8023 E. 63RD PLACE, SUITE 101
- **CITY:** TULSA
- **STATE:** OK
- **ZIP:** 74133

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CLEARSIGN COMBUSTION CORP
- **DATE OF NAME CHANGE:** 20080507

### Attached PDF Documents

**Attachment 1:** `clir-20241231xars.pdf`

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 10-K

(Mark One)

☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2024
OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from ______________ to ______________
Commission file number 001-35521

# CLEARSIGN TECHNOLOGIES CORPORATION

(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of incorporation or organization)

26-2056298
(I.R.S. Employer Identification No.)

8023 East 63rd Place, Suite 101
Tulsa, Oklahoma 74133
(Address of principal executive offices)
(Zip Code)

(918) 236-6461
(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

| Title of each class | Trading Symbol(s) | Name of each exchange on which registered |
| --- | --- | --- |
| Common Stock | CLIR | The Nasdaq Stock Market LLC |

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐ No ☑

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☑

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports); and (2) has been subject to such filing requirements for the past 90 days.

Yes ☑ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☑ No ☐.

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ☐
Non-accelerated filer ☑

Accelerated filer ☐
Smaller reporting company ☑
Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the issuer is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☑

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

State the aggregate market value of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold, or the average bid and asked price of such common equity, as of the last business day of the registrant’s most recently completed second fiscal quarter.

As of June 30, 2024, the aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant, computed by reference to the last sale price of the common equity was $33,474,132.

Indicate the number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date.

As of March 26, 2025, the registrant has 52,418,782 shares of common stock, par value $0.0001, issued and outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

None.

ClearSign

# Technologies Corporation

# TABLE OF CONTENTS

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS AND OTHER INFORMATION CONTAINED IN THIS REPORT 1

PART I 2

ITEM 1: BUSINESS 2
ITEM 1A: RISK FACTORS 15
ITEM 1B: UNRESOLVED STAFF COMMENTS 26
ITEM 1C: CYBERSECURITY 26
ITEM 2: PROPERTIES 27
ITEM 3: LEGAL PROCEEDINGS 27
ITEM 4: MINE SAFETY DISCLOSURES 27

PART II 28

ITEM 5: MARKET FOR REGISTRANT'S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES 28
ITEM 6: [RESERVED] 28
ITEM 7: MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS 29
ITEM 7A: QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK 35
ITEM 8: CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA 35
ITEM 9: CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE 36
ITEM 9A: CONTROLS AND PROCEDURES 36
ITEM 9B: OTHER INFORMATION 37
ITEM 9C: DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS 37

PART III 38

ITEM 10: DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE 38
ITEM 11: EXECUTIVE COMPENSATION 45
ITEM 12: SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS 50
ITEM 13: CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE 53
ITEM 14: PRINCIPAL ACCOUNTING FEES AND SERVICES 54

PART IV 55

ITEM 15: EXHIBITS, CONSOLIDATED FINANCIAL STATEMENT SCHEDULES 55
ITEM 16: FORM 10-K SUMMARY 55

[This page intentionally left blank]

1

# SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS AND OTHER INFORMATION CONTAINED IN THIS REPORT

This Annual Report on Form 10-K, or this “report,” contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the provisions of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Forward-looking statements give our current expectations or forecasts of future events. You can identify these statements by the fact that they do not relate strictly to historical or current facts. You can find many, but not all, of these statements by looking for words such as “approximates,” “believes,” “hopes,” “expects,” “anticipates,” “estimates,” “projects,” “intends,” “plans,” “would,” “should,” “could,” “may,” “will” or other similar expressions in this report. In particular, these include statements relating to future actions; prospective products, applications, customers and technologies; future performance or results of any products; anticipated expenses; and future financial results. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from our historical experience and our present expectations or projections. Factors that could cause actual results to differ materially from those discussed in the forward-looking statements include, but are not limited to:

- our history of losses and expectation that we will continue to experience operating losses and negative cash flows in the near future;
- our ability to successfully develop and implement our technologies and achieve profitability;
- our limited operating history;
- changes in government regulations that could substantially reduce, or even eliminate, the need for our technology;
- emerging competition and rapidly advancing technology in our industry that may outpace our technology;
- customer demand for the products and services we develop;
- the impact of competitive or alternative products, technologies and pricing;
- our ability to manufacture any products we design;
- general economic conditions and events and the impact they may have on us and our potential customers;
- the impact of a cybersecurity incident or other technology disruption;
- our ability to protect our intellectual property;
- our ability to obtain adequate financing in the future;
- our ability to retain and hire personnel with the experience and talent to develop our products and business;
- our success at managing the risks involved in the foregoing items; and
- other factors discussed in this report.

Forward-looking statements may appear throughout this report, including without limitation, the following sections: Item 1 “Business,” Item 1A “Risk Factors,” and Item 7 “Management’s Discussion and Analysis of Financial Condition and Results of Operations.” The forward-looking statements are based upon management’s beliefs and assumptions and are made as of the date of this report. We undertake no obligation to publicly update or revise any forward-looking statements included in this report. You should not place undue reliance on these forward-looking statements.

Unless otherwise stated or the context otherwise requires, the terms “ClearSign,” “we,” “us,” “our” and the “Company” refer to ClearSign Technologies Corporation and, where appropriate, its subsidiary, ClearSign Asia Limited.

PART I

ITEM 1. BUSINESS

Introduction

We design and develop technologies for the purpose of decarbonization and improving key performance characteristics of industrial and commercial combustion systems, including emission and operational performance, energy efficiency, and overall cost-effectiveness. We believe that our patented ClearSign CoreTM technology can enhance the performance of combustion systems in a broad range of markets, including the energy (upstream oil production, midstream gas processing and transportation, and down-stream refining), institutional, commercial and industrial boiler, chemical, and petrochemical industries. Our ClearSign CoreTM technology, which is our primary technology, uses either a porous ceramic structure or metal flame holder device held at a distance from the injection planes of a burner to significantly reduce flame length and achieve low emissions without the need for external flue gas recirculation, selective catalytic reduction, or high excess air systems. To date, our operations have been funded primarily through sales of our equity securities.

Our combustion technology has been successfully deployed in commercial projects such as down-stream refining and upstream oil production. These applications include our process burner, flaring and boiler burner technologies. Both our process burner and boiler burner technology can operate in high-intensity industrial burner applications at sites that are required to meet low air pollutant emissions.

We believe that combustion equipment utilizing ClearSign CoreTM technology is more effective and cost-efficient than current industry-standard air pollution control technologies and can reduce nitrogen oxide (“NOx”) emissions down to the levels required by new stringent emission regulations. NOx is a regulated greenhouse gas pollutant comprised of nitrogen oxide and nitrogen dioxide. These current industry-standard air pollution control technologies include selective catalytic reduction devices (“SCRs”), low- and ultra-low NOx burners, external flue gas recirculation systems and other similar technologies. Such air pollution control systems are widely used in places within our current target markets such as petroleum refining and petrochemical process heaters, large-scale once through steam generators (“OTSGs”), enclosed flares, institutional commercial and industrial boilers and other similar equipment. We believe that our ClearSign CoreTM technology can provide value to our customers not only by helping them meet current and possible future legislative mandates to reduce pollutant emissions, but also by improving operating efficiency and increasing overall return on investment.

Based on the operating data we have obtained from our installed products, burners utilizing ClearSign CoreTM technology can provide increased heat transfer efficiency as compared to other emission reducing technologies. This is consistent with the physics of heat transfer and the mechanisms by which the technology functions. The reported increased heat transfer efficiency may potentially result in cost savings in the low to mid-single digit percentage range for burners employing our technology. We believe that these potential costs savings could produce a significantly attractive pay-back period for an investment in ClearSign CoreTM technology-based burners. In addition, because the flame volumes in heaters utilizing ClearSign CoreTM technology are typically small, heaters using our technology are expected to operate at a lower cost, have increased productivity, and require less maintenance and downtime compared to heaters that operate with enlarged flames produced by traditional low NOx burners. The flames in a ClearSign CoreTM system are established from a predominantly premixed stream of fuel, combustion air and flue gasses stabilized on a downstream structure that promotes turbulence and ignition with minimal “bulking up.” In comparison, flames resulting from the traditional legacy process of slow mixing of the fuel and air, and dilutive inert flue gasses have a much larger size. With a lower volume flame in a ClearSign CoreTM system, surfaces in the heater or boiler experience less touching by the flame and it is anticipated that our systems can virtually eliminate flame impingement. Our technology also enables burners to function better in tightly spaced heaters compared to the flames of traditional low NOx burners. Most importantly, using our technology has the potential to decrease process downtime required during installation compared to retrofits utilizing the legacy technology of SCRs or flue gas recirculation systems.

We are also designing and commercializing a range of sensing products called the ClearSign Eye for two potential markets. The primary addressable market is similar to that of our ClearSign CoreTM technology, although not

limited to regions requiring emissions reduction. The flame sensing products are applicable to all installed burners that use a pilot for ignition, including in markets and regions beyond those where reducing emissions is a high priority. Like our burner technology, our burner sensing technology is being developed to provide convenient replacement and retrofit solutions for existing equipment as well as for inclusion in newly built equipment.

The secondary potential market for our sensing technology is outside of the typical combustion industry and includes transportation industries. We are collaborating with Narion Corporation to further develop our technology for this industry, which allows us to incur minimal costs while pursuing this market opportunity. While use of this fundamental technology in applications intended for transportation markets is proven, the development and refinement of specific products, obtaining the certifications required for commercial deployment and establishing an efficient manufacturing source and channels to market will take some time, and we cannot assure that these goals will be achieved. We believe that the opportunities for application of our sensing technology in the transportation market are global and of great value, but it will also take longer to commercialize products targeted for this market for the reasons stated above.

Overall, our sensing technologies could provide future diversification as well as the opportunity for continued business expansion and growth beyond the maturation of our combustion-related businesses.

## Our Industry

The combustion and emissions control systems markets are significant, both with respect to the wide array of industries in which the systems are used and the amount of capital spent installing and upgrading the systems. Combustion systems are used to provide heat for many different industrial and commercial processes, including boilers, petrochemical process heaters, and waste disposal systems. In order to maximize energy efficiency while keeping pace with regulatory guidelines for air pollution emissions, operators of combustion systems are continually installing, maintaining, and upgrading a variety of costly process control, air pollution control and monitoring systems. Although we believe that there are many potential markets for our ClearSign CoreTM technology, to date we have limited the introduction of this technology to petroleum refining process heaters, energy infrastructure process heaters, boilers for steam and hot water generation, boilers for building heating systems, and enclosed flares. We have initially targeted these markets for various reasons, such as, but not limited to: (i) environmental regulations imposed on these markets, (ii) total available market size, (iii) this technology being the most readily adapted to the needs of these industries and (iv) management experience and expertise.

Our initial target markets center on the energy sector, including downstream oil refineries through the use of process heaters and boilers as well as upstream crude oil production through the use of OTSGs and wellhead enclosed flares. We believe operators in our domestic target markets are under pressure to meet current and proposed federal, state and local pollution emissions standards. The standards applicable to our target markets have been developed over the past 50 years with broad political input. Due to the localized effects of poor air quality, we expect these standards to continue to become more stringent regardless of political leadership. As an illustration, air pollution emission standards are most stringent in the states of California and Texas, which historically have had leadership from different political parties. We believe this to be the case in the U.S. and worldwide in most major developed and developing countries. As a result, these standards are a significant driver for our development and sales efforts. We believe that our ClearSign CoreTM technology can provide a unique, cost-effective pollution control solution for operators in comparison to known competing products.

In the U.S., emissions standards largely emanate from the Clean Air Act of 1963 (as amended, the "Clean Air Act"), which is administered by the Environmental Protection Agency ("EPA") and regulates six common criteria air pollutants, including ground-level ozone. These regulations are enforced by state and local air quality districts as part of their compliance plans. As a precursor to ground-level ozone, NOx is a pollutant that is regulated by local air quality districts in order to achieve the EPA limits. The 8-hour ground-level ozone regulations have been reduced from 80 parts per billion ("ppb") in 1997, to 75 ppb in 2008, and 70 ppb in 2015, with the requirement of realizing these levels approximately 20 years following the year of legislation.

3

We have noted that local air quality districts designated by the EPA as “severe non-attainment zones” in California and Texas have undertaken a review of their air pollutant emissions regulations. These reviews are ongoing, in most regions, but two important regions have recently amended their local regulations to improve air quality. In December of 2020, the San Joaquin Valley region of California revised its regulations to require significant reductions in target NOx emissions from boilers, steam generators and process heaters. And, in November of 2021, the greater Los Angeles area also revised its regulations. These revised regulations substantially reduced target emissions for process heaters, boilers and other similar equipment pursuant to a new and comprehensive Best Available Retrofit Control Technology (“BARCT”) analysis, which we believe will result in an increased demand for our services and products.

On February 2, 2024, the South Coast Air Quality Management District of California (“SCAQMD”) as part of its periodic public participation process to enhance existing Best Available Control Technologies (“BACT”) determinations, assessed the process burner performance of our ClearSign CoreTM burner technology in certain currently operating customer installations. As a result of this assessment, SCAQMD approved new BACT performance guidelines for both single and multi-burner configurations. BACT guidelines are periodically updated by SCAQMD to reflect advancements in technology and to ensure affected equipment utilize the most efficient technologies. While the establishment of a new BACT benchmark does not specifically endorse ClearSign or our products, it does establish a limit in the industry that favors our products. According to SCAQMD, BACT is the most stringent emission limitation or control technique for a class and category of equipment that is “Achieved in Practice,” or “Contained in a State Implementation Plan” (“SIP”), or “Technologically Feasible.”

In addition, new regulations are starting to be adopted with respect to the NOx emissions of enclosed ground flares, which historically have not been viewed as a source of NOx emissions or subject to the same level of regulation. We believe that our ClearSign CoreTM technology is well-suited to address the challenges faced by oil producers and other industries in complying with current and predicted future local air emission standards. There are multiple ClearSign CoreTM flare applications now operational in California with NOx emissions below the levels required by new regulations.

In addition, we believe that current emissions standards in Europe, the Middle East, parts of Asia and Canada will continue to become stricter as these jurisdictions seek to achieve cleaner air. Existing and new emissions standards in such jurisdictions may create additional market opportunities for us. To date, we have one installation operating in the refinery of a major global oil refiner in Europe.

The current environmental impetus to reduce carbon dioxide emissions has created an interest in burner technology that can use hydrogen as a fuel source. Because hydrogen burns at a higher temperature than most other fuel gasses, it tends to create more NOx emissions. ClearSign CoreTM burners have demonstrated the ability to burn fuels with up to 80% hydrogen while still controlling NOx emissions to meet required regulatory levels. We believe that we can extend the capability of our ClearSign CoreTM technology to burn “pure” hydrogen fuel.

## Our Proprietary Technology

### ClearSign CoreTM Burner Technology

The name “ClearSign Core” was adopted to describe the inclusion of ClearSign’s burner technology in the products of original equipment manufacturers (“OEM”). Including our technology in OEM burner products enables us to leverage our technology by providing OEMs with the ability to offer a new product range with our technologies’ unique capabilities and differentiated product performance.

4

Our ClearSign CoreTM burner technology consists of an industrial burner body and a downstream flame stabilizing structure made of either porous ceramic or metal. When the unreacted mixture of gaseous fuel and air is directed at the flame stabilizing structure, the mixture ignites and the flame forms either within or immediately downstream from the structure itself. Because the fuel and air have more time to become a homogeneous mixture, NOx-forming hot spots and chemistry typically produced by such hot spots is reduced. In addition, the mixing and combustion propagating from the flame-stabilizing structure results in a dramatically shorter flame. The ability to modify the flame stabilizing structure enables a high level of control over the flame shape for optimization in a wide range of different applications. For example, we believe our ClearSign CoreTM products, without any external fans or associated power, can significantly reduce the harmful emission of NOx to levels of 5 ppm or below, depending on the application. The shorter flame in a ClearSign Core product can also potentially allow a furnace to operate at a higher capacity. We believe that heaters using the ClearSign CoreTM will be able to remain in operation for an extended time before the need for maintenance as its flame structure and heat transfer profile minimize the possibility of flame impingement, reduce the likelihood of carbon deposits forming on the inside surfaces of the process tubes (coking) and reduce the likelihood of process tube failure all while operating with enhanced thermal efficiency.

![img-0.jpeg](img-0.jpeg)
Refinery and Petrochemical Heater Technology

![img-1.jpeg](img-1.jpeg)
Boiler Technology

# ClearSign CoreTM Process Burner Technology

Our ClearSign CoreTM burners provide a simplified, pre-engineered and standardized direct burner replacement for traditional refinery process heaters. We believe that this product minimizes the customized engineering associated with retrofits and lends itself to mass production. The product was designed to enable quick and easy installation in single burner or multi-burner heaters or furnaces. We believe that the simplicity of the actions required to retrofit refinery process heaters with the ClearSign CoreTM technology, and the potential ability to install these burners will potentially contribute to demand for our ClearSign CoreTM process burners.

6

# ClearSign CoreTM Boiler Burner Technology

Our ClearSign CoreTM technology for boiler burners is essentially the same as our technology for process burners, but with different component details. Boiler burners have a different orientation and internal chamber dimensions, operate with a relatively high combustion air pressure, and, in the case of small fire tube boiler burners, have a lower fuel gas pressure. Our go to market strategy of incorporating the ClearSign CoreTM technology into a typical OEM process burner is the same as for our boiler burners.

# ClearSign CoreTM Flaring Burners

Our ClearSign CoreTM flaring technology incorporates the same mechanisms as our burner technology, namely directing the fuel gas (typically waste gas), into an air stream with that air and gas mixture forming a flame stabilized downstream on a flame stabilizing structure. This technology has been configured into standard modular designs that can be used individually, or in combination, to provide a flare product with extremely low NOx emissions. We have designed standardized flare configurations with standard firing capacities that can be combined in varying quantities to produce flares with different firing rates.

# ClearSign Eye Flame Sensor

The ClearSign Eye flame sensor is an electrical flame sensor for industrial applications. Unlike the traditional technology, called "flame rods," the ClearSign Eye sensing electrodes do not need to make contact with the flame. We are continuing to pursue "first adopter" installation opportunities for this patented sensing technology. We have multiple options open to us as channels to market, one of which includes manufacturing the sensors ourselves as an OEM and selling them to customers either directly or indirectly through intermediaries, and another being licensing. We believe our sensing technology is valuable because it potentially provides a very reliable alternative or replacement technology for critical industrial burner safety equipment. The currently available flame sensors are unreliable and require frequent maintenance. Our flame sensors can potentially be used with other combustion equipment such as flares, thermal oxidizer burners and boiler burners.

Our sensing technology can detect the capacitance of a flame while being physically outside of the flame envelope. As a result, our sensors can be easily retrofitted into existing burner technology. In addition, because the entire sensor probe can be positioned in a cool region, the ClearSign Eye can be manufactured with electrodes that have an optimized shape to provide the most robust signal and using processes and materials that provide an extremely long functional life.

# Development of Our Technology

To date, we have deployed our ClearSign CoreTM technology through retrofits and replacements of existing burners and complete replacement units in the case of our process burner and boiler burner products. Retrofits often involve engineering around an existing burner architecture that can complicate the ClearSign CoreTM burner installation, whereas replacements are more straightforward and more amenable to being sold and installed by third parties, enabling more expansive channels to market. Because of this, we have focused the development of our technology to provide designs that can be included into our prospective customers' equipment as self-contained modules or assemblies rather than projects involving the re-engineering of existing burner systems. In this form, we believe that the ClearSign CoreTM burner technology is ideally suited for installation into new heaters and burner replacements, including heater and furnaces requiring large quantities of burners. In addition, this strategy also provides for simple new burner installations, or burner replacements to reduce emissions in boilers ranging from small fire tube boilers to large water tube boilers. We have also developed the ClearSign CoreTM flare technology into similar repeatable forms to aid its inclusion in standard industry installations on a commercial scale with multiple installations now operational in California.

For simplification and marketing, we have adopted the term "ClearSign Core" to refer to the inclusion of our standardized proprietary combustion technology into a variety of combustion equipment types including, but not limited to, process heater burners, boiler burners, burners for thermal oxidizers and flares. Earlier ClearSign technology-based heater retrofits, in which a continuous ceramic "wall" was suspended above the existing burners, also continue to

operate, and are referred to as “Duplex” technology. Although the combustion controlling principles of both the “ClearSign Core” and “Duplex” technologies are the same, ClearSign CoreTM products have standardized technology and we believe they are easier to use and have a different channel to market.

ClearSign CoreTM burners currently operate in multiple boilers, heaters and flares and meet new compliance standards enacted by California air authority. We also have products in commercial use in Europe. As noted above, our principal technologies have been developed into standardized designs. Our business development activities are now focused on developing customer acceptance and adoption within what we believe are the most efficient channels to market. The industries using our technology take a conservative approach to adopting new technology and place significant reliance on references from existing customers when selecting new equipment. A major focus of our current business development activities is to make early sales and build our reference list in both the process burner and boiler burner industries. We also seek to provide comprehensive technical support to our sales efforts as well as demonstrate our technology and products in operation. We are currently able to demonstrate our products while operating in rental boilers, industrial scale process burner test furnaces, and at customer locations when permissible.

## ClearSign Core Technology Product Applications

To date, we have deployed our ClearSign CoreTM technology through the retrofit or replacement of existing burners. As noted above, retrofits often involve engineering around an existing burner architecture that can complicate the installation. By developing our ClearSign CoreTM technology into a replacement product, we have been able to standardize our designs and simplify supply-chain demands. In addition, we have enabled collaboration with other commercial equipment suppliers with the intent to incorporate our ClearSign CoreTM technology into their standard product lines. We believe that this further development of our products has greatly increased our ability to collaborate with partners to extend our potential market reach and the resources we make available to our prospective customers.

## Process Heaters in the Oil Refining, Petrochemical and Gas Processing Industries

To date, we have retrofitted six process heaters with our new ClearSign CoreTM process burners for refineries and fuel distributors, some of which are owned by global supermajor companies and Fortune 500 companies. Sites include four locations in California and one in Europe. The ClearSign CoreTM design provides a more simplified, pre-engineered and standardized direct burner replacement for traditional refinery process heaters that we believe can be mass produced and reduce the need for the customized engineering associated with typical retrofits. The ClearSign CoreTM design (including the boiler burner version) is our most developed burner product. It operates essentially in the same way as a standard burner, including fitting into a heater and integrating with existing control systems. We believe that this product is suitable for licensing as well as potential manufacturing arrangements with OEMs that have established manufacturing and distribution capabilities. At this time, we have a collaboration agreement in place with Zeeco Inc., one of the world's largest combustion equipment manufacturers (“Zeeco”). The selling and marketing of our process burners pursuant to this agreement, however, is contingent upon terms still under negotiation.

In 2021, we received our first international purchase order for a ClearSign Core refining process heater from a global supermajor refining company. This marked the second order we received from a global supermajor company. This international order was installed in 2021 and successfully placed it into full operation by the customer in January 2022. In addition, we fulfilled a multi-burner order for a Fortune 500 infrastructure company that continues to consistently meet all performance requirements including compliance with the California site’s air quality permit. The process burner installed at this site was used by SCAQMD to set new BACT guidelines (see discussion above under the “Our Industry” section). We also received a purchase order in 2022 from a California refinery for our ClearSign CoreTM process burners, amounting to twenty burners. Due to project delays, which were outside of our control, the process burners for this order were shipped to the jobsite during the third quarter of 2024 but the installation into the customer’s heater is now expected to occur during the third quarter of 2025. On May 18, 2023, we received an order for thirteen process burners from an existing California refinery customer. The order covered retrofitting two heaters, both of which have been installed and are currently operating. The process burners installed in both heaters have passed the customer’s NOx emissions permit level, which were validated by third-party inspectors.

7

In 2023, we received a purchase order from a heater manufacturer to install a modified ClearSign CoreTM boiler burner into a horizontally fired process heater. The end customer was a chemical company located in Texas. This project was a significant achievement for us, since it gave us the ability to demonstrate a new product offering. Since that first order in 2023, we have received three more orders for this same type of application. We believe these orders are representative of an underserved and growing market opportunity in low emissions burners for horizontally fired process heaters. Two of these orders are in the state of Texas, and are believed to be a response to anticipated changes to Texas air emissions regulations, which we expect will ultimately lead to additional demand for our technology.

As we seek to expand the markets into which we can sell our products, we plan to continue extending the range of ClearSign CoreTM process burners to enable the replacement of other burner shapes and configurations, as well as for use in alternate process applications.

## Hydrogen Process Burners

We are currently in the research and development phase to design a one-hundred percent hydrogen capable ClearSign CoreTM process burner. The goal of this project is to develop an ultra-low NOx hydrogen burner, which we believe will enable the adoption of hydrogen fuel for industrial heating, leading to reductions in the industrial emissions of both carbon dioxide and nitrogen oxides. Current burners and previous efforts to decarbonize industrial combustion processes through the utilization of hydrogen fuel are inhibited by the lack of industrial hydrogen burners capable of burning pure hydrogen while controlling emissions of NOx emissions to the most stringent levels required in the industry.

We have received two grants from the Department of Energy ("DOE") to fund the development of this technology. In total, the DOE awards approximate $1.9 million in the aggregate, with a target end date occurring in 2025. See "Note 12 - Government Assistance" for further details about these monies.

## Industrial Commercial Boilers

Boilers are used in many industrial applications, and smaller scale commercial and residential applications, to generate steam and hot water. Several boiler manufacturers produce many styles of boiler equipment for these different applications. In our target markets, boilers exist in two different industry-standard forms: water tube, which tend to be larger and in which the water or steam flows through a series of tubes that surround the space in which the flame forms; or fire tube in which the flame is formed inside a large tube that passes through the outer vessel holding the water.

Our "Core" boiler burner technology has been developed to enable it to be used in a series of consistently designed firetube boilers. For fire tube products, we have developed our own patent protected burner replacement product that is similar in concept to our ClearSign CoreTM burners for process heaters. These boiler burners have achieved performance levels meeting the most stringent new California NOx regulations, in a typical commercial fire tube boiler produced by one of the industry's largest suppliers in the U.S. For instance, through our collaboration agreement in place with California Boiler to sell, deliver, install and service fire tube boiler burners in the U.S., we were able access larger sizes of fire tube boilers in order to verify the function of a range of fire tube boiler burners.

In 2023, we received two purchase orders for our ClearSign Core boiler burner technology. Both boiler burner purchase orders were sold as a package with our collaborative partner, California Boiler, and its subsidiary, Rogue Combustion, into the San Joaquin Valley Air Pollution Control District of California. The NOx emission permits for these boilers vary, with one boiler noted at 5ppm and the other at 2.5ppm. Third-party source testing has validated the 5ppm and 2.5ppm emission orders. In 2024, we received three additional orders from Rogue Combustion with one of these three orders accompanied by a letter of intent for three follow-on orders.

## Wellhead Enclosed Flares

Based upon discussions with local regulators and the examination of regulatory reports, we believe that certain regions are targeting enclosed flare emissions for increased future regulation. California, for example, has already added new low NOx emissions regulations for flares. We have adapted ClearSign CoreTM technology to suit this application.

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Our collaboration agreement with the field engineering and servicing company California Boiler includes flare sales and installation. To date, we have four flare units installed and operating in California resulting from this California Boiler collaboration agreement.

## OTSGs for the Enhanced Oil Recovery Industry

We have successfully installed our Duplex technology in three OTSG projects in the enhanced oil recovery industry in California. Field data reported by our customers indicates significant efficiency improvements resulting from the installation of the ClearSign technology. We believe our new standardized boiler burner range of products is also well suited to this application.

## Sensing Products

We are currently engaged with a prominent refining customer as a first adopter to install our flame sensors on burners in one of their heaters facilitating our first field demonstration. Although we have not yet completed the product launch of our sensing products and subsequent commercialization thereof, we have obtained clear and consistent customer feedback guiding its first application. The target market for this technology is potentially every burner with a pilot on which flame sensors are deployed, providing a global and very high-volume opportunity. This market is not limited by emissions mandates or the type or manufacturer of the burners. The product has value for retrofit applications, where it is applied to existing burners, and for new burners, where it can be installed in burners by OEMs.

We are assessing the possibility of manufacturing the sensing products ourselves as well as partnering with one or more established OEM suppliers. Demonstration units have been manufactured and we currently have the ability to manufacture the sensor ourselves for the foreseeable future. We are also exploring alternative paths to monetize the technology, including opportunities to license our technology.

The fundamental technology for the sensors envisioned for transport applications is the same as for the flame sensors, but the application and form of the final product will be very different. We have received notable interest in this product from a major global customer giving us the confidence that there is a potential market for this technology, which is therefore worthy of future investment. This sensor product is in the very early stages of development and would be deployed in a highly regulated environment requiring a thorough product development process. The interest we have received to date, however, suggests that this could potentially be a significant future business opportunity for ClearSign.

## Our Target Markets

Our ClearSign CoreTM products compete in the combustion and emissions control markets. These industries are highly competitive and currently dominated by companies that have comparatively more established products and substantially greater infrastructure, customer support networks, and financial resources. Based on testing and completed field installations to date, however, we believe that our ClearSign CoreTM technology provides several unique and powerful business solutions for our customers, including, but not limited to: (i) overall cost-effective installation, (ii) energy efficiency, (iii) operational performance and (iv) significantly reduced emissions. Further, we believe that our technology is well-suited to create substantial synergistic value by incorporating it into mainstream commercial offerings with the market incumbents, thus leveraging the "ClearSign Core" technology along with the established breadth and capabilities of collaborating companies, such as Zeeco and California Boiler.

We are targeting the following segments of the combustion market for adoption of our ClearSign CoreTM technology:

- institutional, commercial and industrial boilers;
- refining, energy infrastructure and petrochemical process heaters;
- enclosed flares and thermal oxidizers; and
- enhanced oil recovery steam generators

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In each of these segments, we are marketing solutions that include our ClearSign CoreTM technology which we believe could simultaneously improve productivity, operational efficiency and pollution control.

Our target markets are greatly affected by air emission regulations and economic conditions. Accordingly, we prioritize our activities in target market segments geographically based on the needs of the local industries and the current and anticipated future requirements imposed by local environmental regulations. Details regarding the localized effect of environmental regulations in the United States are described in the section of this report titled "Our Industry." In general, our immediate regional opportunities are in the West and Gulf Coasts of the United States.

## Competition and Barriers to Entry

The industry in which we operate is global in scope and populated by large, established suppliers of burners and post-combustion air pollution control systems. These suppliers possess resources that are substantially greater than ours. Worldwide, suppliers of burners and air pollution control equipment include but are not limited to companies such as Callidus, Eclipse and Maxon (all three are subsidiaries of Honeywell), John Zink Hamworthy Combustion (a subsidiary of Koch Industries and including Coen), General Electric, Haldor Topsøe, Hitachi, Linde, Zeeco, Fives Group, Cleaver Brooks, Power Flame (a subsidiary of Aztec Inc.), and others.

These companies provide systems that include low and ultra-low NOx burners, selective and non-selective catalytic reduction systems, and other pollution control technologies. They are well-established and their combustion and emissions control systems are based mostly on mature, well-understood and proven technologies. As a result of the relatively slow pace of developing and adopting innovation, we believe the technology and products currently being offered by our large competitors have become commoditized with differentiation between suppliers most often based on price. These industry characteristics provide both an opportunity and a barrier to more nimble, disruptive companies.

From a customer's perspective, installation of legacy air pollution control technologies is viewed as a method of avoiding fines, as a cost of doing business, and as a means to operate within current and anticipated future regulatory requirements.

Unlike most other kinds of capital equipment that provide an economic return through enhanced productivity or efficiency, we believe customers of traditional emissions control equipment do not expect any positive return on emissions control investments other than the ability to continue to operate or avoid fines. We believe the ClearSign CoreTM suite of products are further differentiated from its competitors because they give prospective customers the opportunity to greatly reduce capital investment and, in certain cases, realize a return on investment through increased efficiency and/or increased productivity.

As indicated above, we are seeking to develop our business in the combustion and emissions control market and to establish ourselves in a highly competitive industry among companies that have substantial financial resources, a well-developed infrastructure and established products. Our business development strategy seeks to obtain recognition of our technology's value while minimizing the challenges inherent in this market including the strengths of the other market participants.

Major barriers faced by a new equipment manufacturer seeking to enter this market include:

1. Developing engineering, order fulfillment and customer service staff: Especially in the refining and petrochemical industries, customers require specialist support throughout the life cycle of the combustion equipment including with order execution when purchasing. Recruiting and developing sufficient staff with the special skills necessary to provide the level of service required by customers in this market would take time and result in a significant ongoing overhead cost.
2. Developing operational infrastructure: Especially in the refining and petrochemical industries, customers require thorough quality assurance procedures, including demonstration of an item from their order, to prove that it meets performance guarantees. This requires, among other things, having access to a test furnace. Developing such an operation would require significant investment and ongoing costs.

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3. Conservative customers: Our customers are very careful and methodical about adopting a new technology or product because of the complexity of their infrastructures, the cost of downtime in any part of a processing plant and the potential safety hazards of their operations.

4. Profit opportunity: There is very little differentiation between the products offered by the established burner equipment providers, which results in thin profit margins for the sale of new or replacement burners. A significant portion of a company's profit results from the sales of replacement parts and equipment upgrades. Any new entrant without a differentiating technology will not have this established source of significant and immediate profit.

## Go to Market Strategy

We developed our “go to market” strategy for the ClearSign CoreTM combustion business considering our strengths and weaknesses. The most important weaknesses are related to the barriers to entry identified above. We are a small company with limited financial resources and do not have the infrastructure to meet the requirements of our sophisticated target global customers without significant investment and increase in operational costs. Although we have highly skilled and experienced employees, we do not have the manpower to provide comprehensive service and customer support ourselves. We believe that it is in the best interests of the Company and our stockholders to develop our business utilizing an “asset light” model. Accordingly, we seek to collaborate with strategic partners to the extent possible to sell our products and maximize the profitability of those sales.

We believe that our technology is our main strength, which has been developed to provide a standard set of “core” components that can be incorporated into any generic OEM burner body. These components enable unique performance that minimizes emissions and controls flame size. We believe that our strengths also include the market opportunity potentially created by new and anticipated environmental emissions control regulations. These regulations will potentially require combustion performance that either exceeds the technology available from the incumbent equipment manufacturers or requires retrofitting existing equipment with a post-combustion clean up apparatus. Installing clean-up apparatus is very expensive especially for small to mid-sized heaters. We believe that the incumbent burner OEM product development approaches are, and will continue to be, incremental in nature, and are unlikely to pose a significant threat to the value provided by ClearSign Core technology in the foreseeable future.

## Manufacturing Footprint and Product Quality Strategy

Our business has been, and continues to be, developed with the goal of combining our technology with the infrastructure and resources of major OEM equipment manufacturers. Through such collaborative arrangements, OEM burner manufacturers can reap the benefits of adding truly differentiated and unique product lines to their offerings and ClearSign can overcome the barrier to market of needing to build capital and operating expense-intensive infrastructure and hiring a large specialist staff. We also believe that having orders fulfilled by a well-known and trusted supplier will reduce the risk, as perceived by prospective customers, of dealing with a small company. We expect that developing strategically chosen collaborative partnerships will result in supplying ClearSign CoreTM technology to major global customers in large quantities together with the attendant engineering, quality control, customer support and project management services required by these sophisticated customers. We also believe that our collaborative partnerships will enable our OEM partners to offer a unique product in the marketplace and provide both parties with a potentially significant commercial opportunity. Forming such alliances is expected to dramatically accelerate the global sales and market adoption of our technology.

As announced in June 2019, we already have an agreement in place with Zeeco, who is one of the world’s largest burner manufacturers, to globally manufacture ClearSign CoreTM process burners. In December 2024, Zeeco and ClearSign announced the launch of a co-branded ClearSign Core process burner product line. We believe that this announcement marked the next stage of evolution in our relationship with Zeeco, where we will work together to market and sell ClearSign CoreTM technology. We are continuing to negotiate this next phase of our relationship, but we view this announcement as a commitment to solidify our shared marketing and sales efforts of ClearSign CoreTM technology going forward.

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In addition, we have a collaborative agreement with California Boiler to sell and produce both fire tube boiler burner and flare products. California Boiler created a wholly owned subsidiary Rogue Combustion for the purpose of marketing boiler burner systems solution using our ClearSign CoreTM technology, which are branded as Near Zero NOx (“NZN”) and Sub 5ppm NOx (“S5”) and Sub 9ppm NOx (“S9”) solutions. Typically, boiler burner customers rely on integrated service providers to design, install and service boiler burner systems. Our collaborative relationship with California Boiler and Rogue Combustion aligns with our “asset light” philosophy by providing us with a low-cost path to market, by limiting human capital investment in maintenance and installation technicians.

## Sales Channel and Marketing Strategy

In addition to targeting OEM manufacturers and service providers to augment our manufacturing footprint and on-time service capabilities, we target sales and marketing efforts at OEM heater companies and engineering companies supporting our refining, petrochemical and energy infrastructure customers. By focusing on this sales channel, we believe we can quickly gain repeat sales given these customers act as a conduit to multiple end users, which also allows us to maximize the reach of our limited selling and marketing resources. In 2024, as a result of adopting such go-to-market strategy, we received multiple orders originating from a single heater OEM.

We value and nurture our relationships with end users, and we view this sales channel as a critical path to overall market acceptance, since end users ultimately own and operate our equipment. Further, by maintaining and growing such relationships, we were able to successfully enter the market and generate the first adopters of our technology. We further believe that fostering these relationships will help us drive demand for our products downstream to OEM heater manufacturers and engineering service companies. We expect that these end users, as first adopters of our technology, will also play a vital role in future sales efforts by providing references to prospective customers, as, based on our experience, prospective customers frequently request a reference from an existing customer.

Another aspect of our marketing strategy relies on obtaining reputable third-party validation of our technology by demonstrating that our burners can meet or exceed the operational characteristics we set out to achieve. As noted above in the “Our Industry” section, the SCAQMD approved new BACT performance guidelines for both single and multi-burner configurations using our burners as part of an assessment review. While BACT guidelines do not specifically endorse our technology, we believe these new guidelines reinforce the viability of our burners’ operational capabilities to any industry skeptic. In addition, we participated in a study executed by the California Gas Emerging Technologies (“GET”) program to test and quantify the emissions improvements and efficiency gains of our ultra-low NOx boiler burner as compared to a conventional (or baseline) ultra-low-NOx burner. ICF a global advisory and technology service company, released its independent report on October 2, 2024, detailing the results of this study. In summary, our technology reported fuel savings at 3.3% when operating at sub-2.5 ppm NOx and 4.7% at sub-9 ppm NOx; electricity savings reported 7% at sub-2.5 ppm NOx and 25% at sub-9 ppm NOx. We believe these third-party reviews of our technology play a critical role in proving the efficacy of our technologies and dispelling industry skepticism.

## Pricing Strategy

We believe that the unique capabilities of our technology improve combustion equipment performance and provide significant economic value to our customers compared to the next best alternative solutions available. As a result, we expect that products containing ClearSign CoreTM technology will sell at prices based on the value they offer rather than pursuant to standard competitive pricing that our competitors are forced to use in these mature markets.

## Our Business Segment and Major Customers

We conduct our business activities and report financial results as one business segment. Our business segment engages in the design, development and sale of combustion technologies that improve the performance and cost-effectiveness of industrial combustion systems. The presentation of financial results as one reportable segment is consistent with the way that we operate our business and the manner in which our chief operating decision maker, currently our Chief Executive Officer, manages our operations for purposes of allocating resources and assessing financial results.

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Our operating activities are substantially all located within the United States, and our customers located in the United States accounted for 100% of revenues in the fiscal years ended December 31, 2024 and 2023. Our two California refinery customers accounted for 86% and 87% of our annual revenue for the years ended December 31, 2024 and 2023, respectively. No other customer represented greater than ten percent of annual revenues for the years ended December 31, 2024, and 2023.

|  | For the Year Ended December 31, |  |
| --- | --- | --- |
|  | 2024 | 2023 |
| Customer A | 59% | 28% |
| Customer B | 27 | 59 |
|  | 86% | 87% |

## Suppliers and Subcontractors

Due to our "asset light" model, we use subcontractors to source, warehouse and manufacture our products. This model allows us to maximize the value of our limited resources while minimizing capital investment. Our subcontractor, for the process burner product line, is intentionally single sourced through a collaborative agreement with a well-known and established industry leader, Zeeco. Our boiler burner product line is not dependent upon a single-sourced subcontractor. While we continuously assess, for any improvements in productivity and supply chain efficiency, there can be no assurance that our subcontractors will not experience supply interruptions, production capacity constraints or working capital limitations, which could adversely affect our business.

Raw steel and fabricated steel parts are a major component of our product cost, purchases of which are subject to the needs and specifications of our customers or subcontractors. Periodic changes in the price of steel may affect our final product pricing to customers. In addition, increases in the costs of raw steel or other supplies may also increase our working capital requirements, warranty obligations and product profitability.

Supply interruptions, tariffs or price increases may slow production, delay shipments to our customers or increase production costs in the future, any of which could adversely affect our financial results; however, we intend to pass along production cost increases to customers to the extent we deem appropriate. We expect that delays, interruptions or non-optimal scheduling of production related to interruptions in raw materials supplies would result in an increase to our production costs. We can give no assurance that global supply-chain constraints or geopolitical conflicts will not adversely affect our ability or our subcontractors' ability to procure raw materials and components necessary to build our products.

## Research and Development Program

The experience and industry contacts of our management team and consultants, along with potential customers in the petroleum, petrochemical, and industrial steam applications industries inform our research and development program. Field evaluation agreements, research agreements, and memoranda of understanding with potential development partners, customers and research institutions support this process. Our research and development activities make use of employees and consultants who are experts in the areas of industrial combustion, statistical experimental design, fluid mechanics, computer modeling techniques and heat transfer.

With the maturation of our ClearSign CoreTM technology, our development process has transitioned from research to commercialization. This has included optimizing the technology to perform in a manner readily adoptable by our prospective customers and easy to incorporate into the burner structures of our collaborative alliance partners. This later phase of development is influenced by customer feedback, product and component standardization, design for manufacture and inventory management simplification, both with respect to the manufacture of and lifetime support for our products.

We will continue to assess research and development opportunities to develop new product offerings where appropriate based on customer feedback and market trends. We are currently continuing to develop our flame sensing

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and hydrogen burner technology, which is discussed in detail under the “ClearSign CoreTM Technology Product Applications” section above in addition to the expansion of our burner technologies, and potentially other technologies aligned with our expertise and business focus, into adjacent customer applications and market verticals.

## Intellectual Property Protection

We have generated inventions that we believe to be patentable subject matter and for which we have been seeking protection through patent application filings. As of December 31, 2024, we have 74 active patent grants and another 23 patents pending with Patent Offices in the United States, China, and various European countries. We maintain an active review process to monitor for new inventions across the globe that threaten our intellectual property protection.

We cannot predict when our patent applications may result in issued patents, if at all. Further, we may modify a patent application in the future as we develop additional information. As a result, we may create additional patent applications from an existing application, consolidate existing patent applications, abandon applications, or otherwise modify applications based upon our judgment in order to protect our intellectual property in a reasonably cost-efficient manner.

## Government Regulation

Government regulation, particularly with respect to the environment, is likely to play an important role in shaping our product mix and offerings. In addition, field implementation of our technologies requires permits from various local, state and federal agencies that regulate mechanical and electrical infrastructure and fire and air pollution control.

We believe that we offer major advances in emissions reductions and efficiency improvements. We also believe that emissions regulations could require a reduction in pollutants such as NOx thereby potentially enhancing market demand for our technology upon implementation of any such regulations. Possible legislation related to greenhouse gases, boiler Maximum Available Control Technology (“MACT”) rules, or other general reductions in required pollutant levels globally, especially in the U.S. could bolster our ability to meet our business objectives. Although the timing of any such regulations is uncertain, the general trend over the last decades continues to be government-mandated reduction for all criteria pollutants. Ultimately, it may be possible for our technology to achieve BARCT and/or MACT designation. We believe that the availability of our technology alone may accelerate the government's willingness to adopt more stringent environmental regulations. Further, we believe efficiency improvements, combined with the elimination of flame impingement, could generate market demand regardless of the existing regulatory framework because the potential efficiency, productivity and savings gains from our products could result in the adoption of our technology.

At this time, we believe that the current U.S. administration does not support “green initiatives.” Nevertheless, we are not aware of any current or proposed federal, state or local environmental compliance regulations that would have a material detrimental effect on our business objectives or operations. The U.S. environmental regulation that supports the adoption of our technology originates from the Clean Air Act, which had several subsequent amendments specifically targeting NOx emissions, including the 1990 amendments to the Clean Air Act, or the Acid Rain Program, which contained requirements to reduce NOx emissions through the use of available combustion controls. While the current political environment may not be conducive for strengthening emissions controls at a national level, we believe global mega trends induced by social and political sentiment, and local and state regulatory requirements have laid the groundwork for continued support and adoption of our technology. In addition, we do not anticipate any major expenditures to be required in order for our technology to comply with any environmental protection statutes.

## Human Capital

As of December 31, 2024, we had 18 full-time employees, and no part-time employees. Our employees are not covered by collective bargaining agreements, and we believe our relationship with our employees is good.

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# Corporate History

We were incorporated in the State of Washington on January 23, 2008. Effective June 14, 2023, we changed our domicile from the State of Washington to the State of Delaware by means of a plan of conversion. The address of our corporate headquarters is 8023 East 63rd Place, Suite 101, Tulsa, Oklahoma 74133 and our telephone number is (918) 236-6461. Our website can be accessed at www.clearsign.com. The information contained on our website is not a part of this report. We currently operate in the United States. We have a wholly-owned subsidiary incorporated Hong Kong, China, but we are not currently operating in Hong Kong, China, because such entity is in a dormant status, which status became effective on March 12, 2025.

# ITEM 1A. RISK FACTORS

We are subject to various risks that may materially harm our business, prospects, financial condition and results of operations. An investment in our common stock is speculative and involves a high degree of risk. In evaluating an investment in shares of our common stock, you should carefully consider the risks described below, together with the other information included in this report.

The risks described below are not the only risks we face. If any of the events described in the following risk factors actually occurs, or if additional risks and uncertainties later materialize that are not presently known to us or that we currently deem immaterial, then our business, prospects, results of operations and financial condition could be materially adversely affected. In that event, the trading price of our common stock could decline, and you may lose all or part of your investment in our shares. The risks discussed below include forward-looking statements, and our actual results may differ substantially from those discussed in these forward-looking statements.

# Risks Related to Our Business

We are a company with a limited operating history and our future profitability is uncertain. We anticipate future losses and negative cash flows and we may never be profitable.

We are a company with a limited operating history and limited revenues to date. We have incurred losses since our inception and expect to experience operating losses and negative cash flows for the foreseeable future. As of December 31, 2024, we had a total accumulated deficit of approximately $99.0 million. We anticipate our losses will continue to increase from current levels because we expect to incur additional costs and expenses related to commercialization activities, product development, consulting costs, marketing and other promotional activities. In addition, we expect to continue incurring costs related to human capital development and strategic partnership development. We may never generate significant revenue and we may never be profitable.

If we do not receive additional financing when and as needed in the future, we may not be able to continue our development and commercialization efforts and our business may fail.

Our business is capital-intensive and requires capital investments in order for it to develop. Our cash on hand will likely not be sufficient to meet all of our long-term future needs because our target customers are, in general, slow to adopt new technologies, and we anticipate that we will require substantial additional funds in excess of our current financial resources for research, development and commercialization of our technology, to obtain and maintain patents and other intellectual property rights in our technology, and for working capital and other purposes, the timing and amount of which are difficult to ascertain. Until our technology generates revenues sufficient to support our operations, we plan to obtain the necessary working capital for operations through the sale of our securities, but we may not be able to obtain financing in amounts sufficient to fund our business plans. If we cannot obtain additional funding when and as needed, our business might fail.

Market acceptance of our technology and business is difficult to predict. If our technology does not achieve market acceptance, our business could fail.

If we are unable to effectively demonstrate our technology in a timely fashion, gain recognition in our market segments, and develop a critical level of successful sales and product installations, we may not be able to successfully generate sales revenue and our results of operations and financial condition would then suffer. Our ability to obtain future revenue will depend significantly upon achieving a critical mass of market awareness and sales to potential customers of our products. While we plan to achieve this awareness over time, there can be no assurance that awareness of our Company and technology will develop in a manner or pace that is necessary for us to achieve acceptance and profitability in the near term.

Further, we cannot predict the rate of adoption or acceptance of our technology by potential customers. While we have demonstrated our technology, this does not guarantee the industrial combustion market will accept it, nor can we control the rate at which such acceptance may be achieved. In certain market segments of ours, there is a well-established channel with a limited number of companies engaged in reselling to our target customers. Failure to achieve productive relations with a sufficient number of these prospective partners may impede adoption of our technology. Additionally, some potential customers in our target industries are historically risk-averse and have been slow to adopt new technologies. If our technology is not widely adopted in the industrial combustion market, we may not earn enough by selling or licensing our technology to support our operations, recover our research and development costs or become profitable and our business could fail.

Our efforts may never demonstrate the feasibility of our product.

Our research and development efforts remain subject to all of the risks associated with the development of new products based on emerging and innovative technologies, including without limitation unanticipated technical or other problems, our ability to scale our technology to large industrial applications, conditions in the field during installation and the possible insufficiency of funds for completing development of these products. Technical problems, including those specific to customer site implementation, may result in delays and cause us to incur additional expenses that would increase our losses. If we cannot complete, or if we experience significant delays in completing, research and development of our technology for use in potential commercial applications, particularly after incurring significant expenditures, our business may fail.

Changes to environmental regulations could make our technology less desirable.

The negative environmental impacts of industrial activity have given rise to significant environmental regulation in industrialized countries. These regulations are important incentives in the adoption of technologies like ours. To the extent that environmental regulations in the U.S. and in other industrialized countries are modified in the future, or even relaxed, our technology may not produce the results required, or may even be unnecessary, to comply with the modified regulations. If federal, state or local regulatory agencies relax the clean air regulations our technologies are designed to address, or do not effectively enforce them, or our customers cannot obtain air emission permits with our products, or permits to proceed with projects in general, our business and results of operations could be materially adversely affected.

Further, in January 2025, President Trump signed executive orders that, among other things, directed federal executive departments and agencies to initiate a regulatory freeze for certain rules that have not taken effect, pending review by the newly appointed agency head, and called upon the EPA to submit a report on the continuing applicability of its endangerment finding for greenhouse gas emissions under the Clean Air Act and issue guidance on the "social cost of carbon" to consider whether such metric should be eliminated. Moreover, in January 2025, President Trump signed an executive order calling to terminate all environmental justice offices and positions in the federal government, as well as any environmental justice initiatives, programs or other activities. It is unclear the impact the Trump administration or these new executive orders will have on the laws, rules and regulations applicable to us or on our business, financial condition and results of operations, and we cannot predict future developments related hereto.

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We are subject to sustainability efforts risks that could adversely affect our reputation and our business and results of operations.

Views about sustainability- and environmental-related issues are diverse, dynamic, and rapidly changing. For instance, there exists anti-environmental, social and governance (“ESG”) sentiment among certain stakeholders and government institutions, which has gained momentum across the U.S. While many companies and investors continue to focus on ESG matters, there has been an increase in anti-ESG initiatives and sentiment which may serve as a concern in the future, particularly in light of recent executive orders by President Trump. The future impact of any actions by the current administration on existing ESG policies and regulations cannot be predicted at this time, particularly given that such new orders are likely to face legal challenges. However, in the interim, such anti-ESG-related policies, legislation, initiatives, litigation, legal opinions, and scrutiny could result in less demand for our products and offerings, which can affect our business and results of operations. Further, we could be exposed to reputational, financial, and legal risk as a result of anti-ESG policies and regulations that may be enacted under the current administration, and our ability to retain and attract customers and employees may be negatively impacted as a result thereof.

Our revenue has been highly concentrated among a small number of customers, and our results of operations could be harmed if we lose a key revenue source and fail to replace it.

Our annual revenue has been highly concentrated, with a few customers accounting for a significant percentage of our total revenue. For the years ended December 31, 2024 and 2023, our two largest customers represented approximately 86% and 87% of total revenue, respectively. We expect that a relatively small number of customers will continue to account for a substantial portion of our revenue for the foreseeable future.

As a result of this revenue concentration, our results of operations could be adversely affected by the decision of a single key customer to cease using our technology or products or by a decline in the number of customers that are seeking to adopt our technology.

Our revenue concentration may also pose credit risks which could negatively affect our cash flow and financial condition.

We might also face credit risks associated with the concentration of our revenue among a small number of customers. Our failure to collect receivables from any customer that represents a large percentage of receivables on a timely basis, or at all, could adversely affect our cash flow or results of operations.

We may fail to adequately protect our proprietary technology, which would allow our competitors to take advantage of our research and development efforts.

Our long-term success largely depends on our ability to market our technology. We rely on a combination of patents, trade secrets and other intellectual property laws, confidentiality and security procedures and contractual provisions to establish and protect our proprietary rights in our technology, products and processes. If we fail to obtain or maintain these protections, we may not be able to prevent third parties from using our proprietary technologies. Our pending or future patent applications may not result in issued patents. In addition, any patents issued to us, or that may be issued to us in the future, may not contain claims sufficiently broad enough to protect us against third parties with similar technologies or products or from third parties infringing such patents or misappropriating our trade secrets or provide us with any competitive advantage. In addition, effective patent and other intellectual property protection may be unenforceable or limited in foreign countries. If a third party initiates litigation regarding the validity of our patents and is successful, a court could revoke our patents or limit the scope of coverage for those patents.

We also rely upon trade secrets, proprietary know-how and continuing technological innovation to remain competitive. We protect this information with reasonable security measures, including the use of confidentiality and invention assignment agreements with our employees and consultants and confidentiality agreements with strategic customers and partners. It is possible that these agreements may not be sufficient or that these individuals or companies may breach these agreements and that any remedies for a breach will be insufficient to allow us to recover our costs and

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damages. Furthermore, our trade secrets, know-how and other technology may otherwise become known or be independently discovered by our competitors.

We may incur substantial costs as a result of litigation or other proceedings relating to patent and other intellectual property rights.

A third party may sue us for infringing its intellectual property rights. Likewise, we may need to resort to litigation to enforce our patent rights or to determine the scope and validity of third-party intellectual property rights. The cost to us of any litigation or other proceeding relating to intellectual property rights, even if resolved in our favor, could be substantial, and the litigation would divert our efforts from our business activities. Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. If we do not prevail in this type of litigation, we may be required to pay monetary damages and/or expenses; stop commercial activities relating to our products; obtain one or more licenses in order to secure the rights to continue the manufacturing or marketing of our products; or attempt to compete in the market with substantially similar products. Uncertainties resulting from the initiation and continuation of any litigation could limit our ability to continue some of our operations.

A cybersecurity incident or other technology disruptions could negatively impact our business and our relationships with customers.

We use computers in substantially all aspects of our business operations. We also use mobile devices and other online activities to connect with our employees, consultants, suppliers and customers. Such uses give rise to cybersecurity risks, including security breaches, espionage, system disruption, theft, the compromise of trade secrets and inadvertent release of information. Our business involves the storage and transmission of sensitive and/or confidential information and intellectual property, including customers' and suppliers' information, private information about employees and financial and strategic information about us. If we fail to assess and identify cybersecurity risks associated with our operations, we may become increasingly vulnerable to such risks. Additionally, while we have implemented measures to prevent security breaches and cyber incidents, our preventative measures and incident response efforts may not be entirely effective. The theft, destruction, loss, misappropriation, or release of sensitive and/or confidential information or intellectual property, or interference with our information technology systems, could result in business disruption, negative publicity, brand damage, violation of privacy laws, loss of customers, potential liability and competitive disadvantage all of which could have a material adverse effect on our business, financial condition or results of operations.

We cannot guarantee that any collaborative business research and development partnership we enter into will be successful.

Collaborative arrangements involve risks that participating parties may disagree on business decisions and strategies. These disagreements could result in delays, additional costs, risks of litigation, and failure of the development of our technology within the combustion market segment. Success of any collaborative arrangements we enter into will depend, in part, on whether those with whom we collaborate fulfill their contractual obligations satisfactorily. If a party with whom we collaborate fails to perform its contractual obligations satisfactorily, we may be unable to make the additional investments or provide the added services that would be required to compensate for that failure. If we are unable to adequately address any such performance issues, our reputation may be materially adversely affected and we may be exposed to legal liability. Our inability to successfully maintain collaborative relationships, once we enter into them, or to enter into new collaborative arrangements, could have a material adverse effect on our results of operations.

If we are unable to keep up with rapid technological changes, our products may become obsolete.

The market for alternative environmental products is characterized by significant and rapid technological change and innovation. Although we intend to employ our technological capabilities to create innovative products and solutions that are practical and competitive in today's marketplace, future research and discoveries by others may make our products and solutions less attractive or even obsolete compared to other alternatives that may emerge.

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There are inherent dangers involved in the combustion process that utilize our technologies and products and the occurrence of any associated accident may negatively impact our business.

There is inherent danger in dealing with the combustion process. There is additional danger in modifying this process in ways that are new and have only been implemented on a limited basis at a commercial scale. There is only limited data or experience available from the operation of our equipment in both testing and commercial applications to validate suitability for general commercial use. Although we have not yet encountered any areas of risk in the development or testing of our products beyond those already inherent in the combustion process or those particular to an industrial site, we may be exposed to liabilities should an industrial accident occur during development, testing, or operation in our laboratory or during field implementation of our technology. Any such liabilities could have an adverse effect on our results of operations and financial condition and adversely affect our projected development and production estimates.

We depend on approval from various local, state and federal agencies to implement and operate our technology. There is no assurance that these agencies will approve our technology.

Our technology includes enhancement of the combustion process to reduce certain emissions at a lower cost of operation than current air pollution control devices. Field implementation of our technology will therefore require permits from various local, state and federal agencies that regulate mechanical and electrical infrastructure and fire and air pollution control. Our technology may be subject to heightened scrutiny since it will be new to these governing bodies. As such, there may be delays or rejections in applications of portions of or all of our technology in the individual jurisdictions involved.

We are uncertain of our profit margins and whether such profit margins, if achieved, will be able to sustain our business.

We have not fully developed all of our products and those products that have been developed have experienced limited sales. As a result, we cannot reliably predict our profit margins. Our operating costs could increase significantly compared to those we currently anticipate due to unanticipated results from the commercialization process, application of our technology to unique or difficult processes, regulatory requirements and particular field implementations. Further, we envision our pricing to be highly dependent on the benefits that our customers believe they will achieve using our products. Accordingly, we cannot predict whether or when we will achieve profitability, and if achieved, the amount of such profit margins.

Many of our potential competitors have greater resources, and it may be difficult to compete against them.

The combustion industry is characterized by intense competition. Many of our potential competitors have better name recognition and substantially greater financial, technical, manufacturing, marketing, personnel and/or research capabilities than we do. Although at this time we do not believe that any of our potential competitors have technology similar to ours, we are aware certain potential competitors are attempting to develop similar products. Many firms in the combustion industry have made and continue to make substantial investments in improving their technologies and manufacturing processes. In addition, they may be able to price their products below the marginal cost of production in an attempt to establish, retain or increase market share. Because of these circumstances, it may be difficult for us to compete successfully in the combustion market.

The loss of the services of our key management and personnel or the failure to attract additional key personnel could adversely affect our ability to operate our business.

A loss of one or more of our current officers or key employees could severely and negatively impact our operations. We have no present intention to obtain key-man life insurance on any of our executive officers or management. Additionally, competition for highly skilled technical, managerial and other personnel is intense. As our business develops, we might not be able to attract, hire, train, retain and motivate the highly skilled executives and employees we need to be successful. If we fail to attract and retain the necessary technical and managerial personnel, our business will suffer and might fail.

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There are many risks we are exposed to relating to our presence and prior business activities in China.

We are exposed to risks relating to our presence and prior business activities in China. As a result, the economic, political, legal and social conditions in China could have a material adverse effect on our business. In addition, the legal system in China has inherent uncertainties that may limit the legal protections available in the event of any claims or disputes that we may have with third parties, including our ability to protect the intellectual property we may use in China. As China's legal system is still evolving, the interpretation of many laws, regulations and rules is not always uniform and enforcement of these laws, regulations and rules involve uncertainties, which may limit the remedies available in the event of any claims or disputes with third parties. Some of the other risks we may be exposed to include, but is not limited to:

- the Chinese government exerts substantial influence over the manner in which we can conduct business activities;
- restrictions on currency exchange may limit the ability to receive and use cash effectively;
- the Chinese government may favor local businesses and make it more difficult for foreign businesses to operate in China on an equal footing, or in general;
- there are uncertainties related to the enforcement of contracts with certain parties; and
- more restrictive rules on foreign investment could adversely affect our ability to resume our operations in China.

To the extent we resume our operations in China, these risks could have a material adverse effect on our business, results of operations and financial condition.

Finally, the U.S. Foreign Corrupt Practices Act and similar foreign anti-corruption laws generally prohibit companies and their intermediaries from making improper payments or providing anything of value to improperly influence foreign government officials for the purpose of obtaining or retaining business or obtaining an unfair advantage. While we make every attempt to comply with these laws, our operations outside the United States may increase the risk of violating such laws. Violations of these laws may result in severe criminal or civil sanctions, could disrupt our business and result in a material adverse effect on our reputation, business and results of operations or financial condition.

We cannot provide assurance that rising inflation will not adversely affect our operations.

The impact of inflation on our operating results has been moderate in recent years, despite the recent increase in inflation generally across the economy. While inflation has not had a material impact upon operating results, there is no assurance that our business will not be affected by inflation in the future.

Due to the nature of our business and products, we may be liable for damages based on product liability and other tort and warranty claims.

We face an inherent risk of exposure to claims in the event that the failure, use or misuse of our products results, or is alleged to result, in death, bodily injury, property damage, or economic loss.

Although we currently maintain product liability coverage, which we believe to be adequate for the continued operation of our business, such insurance may become difficult or impossible to obtain in the future on terms acceptable to us. Moreover, our insurance coverage includes customary exclusions and conditions, may not cover certain specialized applications and generally does not cover warranty. A successful product liability claim or series of claims against us, including one or more consumer claims purporting to constitute class actions or claims resulting from extraordinary loss events, in excess of or outside our insurance coverage, or a significant warranty claim or series of claims against us, could materially decrease our liquidity, impair our financial condition and adversely affect our results of operations. Furthermore, regardless of the outcome, product liability claims can be expensive to defend, divert the attention of management and other personnel for significant periods of time and cause reputational damage.

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We cannot provide assurance that global supply-chain constraints and the threat of, or implementation of tariffs on imported or exported goods and materials will not adversely affect our commercialization efforts and business operations.

The impact of the global supply-chain constraints has been moderate for our company, reflecting generally modest increases in lead-time commitments from our suppliers and strategic partners. While these constraints have not had a material impact to-date, we can provide no assurance that our business will not be affected by in the future. Our products utilize components manufactured from materials that are frequently imported, and any increase in the cost of materials may increase costs and may impact our profit margin on goods sold. Tariffs applied to exported goods may inhibit our ability to develop our business overseas. In addition, the countries from which our products and materials are manufactured or imported may, from time to time, impose additional quotas, duties, tariffs, or other restrictions on their imports or adversely modify existing restrictions. Adverse changes in these import costs and restrictions, or our strategic partners' and suppliers' failure to comply with customs regulations or similar laws, could harm our business. However, it is not always possible to replace a supplier on short notice without disruption in our operations, and replacement of a supplier is often at higher prices.

Further, the materials that our subcontractors may import from time to time are generally at prices that support our current operating margins. These imports may be subject to custom requirements, tariffs, and quotas set by governments through mutual agreements or unilateral actions. The U.S. tariffs on steel and other imported goods may increase the costs of our foreign sourced materials, and any escalation in the tariffs may increase the impact, including without limitation recent tariffs against goods imported from China, Mexico, and Canada recently enacted by the current administration, as modified from time to time, and any retaliatory tariffs issued in response thereto. In case our operating costs increase materially as a result of any implemented tariffs, in order to sustain current operating margins, we may increase the costs of our products to customers and end users, or find alternative, similarly priced sources that are not subject to tariffs, which may delay our operations. If we are unable to effectively implement countermeasures to any proposed, or implemented, tariffs, our operating margins will be impacted.

Our subcontractors ability to import products in a timely and cost-effective manner may also be affected by conditions at ports or issues that otherwise affect transportation and warehousing providers, such as port and shipping capacity, high demand for ocean freight, labor disputes, hostilities or terrorism against ocean vessels or changes in shipping routes to avoid the same, severe weather, or increased homeland security requirements in the U.S. and other countries. These issues could delay importation of materials, increase our transit costs, or require us to locate alternative ports or warehousing providers to avoid disruption to customers. These alternatives may not be available on short notice or could result in higher transit costs, which could have an adverse impact on our business and financial condition.

We are dependent on third-party suppliers.

Although we are not dependent on any one supplier, we are dependent on the ability of our third-party suppliers to supply our raw materials, such as raw steel and fabricated steel. The third-party suppliers upon which we depend may default on their obligations to us due to bankruptcy, insolvency, lack of liquidity, adverse economic conditions, operational failure, fraud, loss of key personnel, or other reasons. We cannot assure that our third-party suppliers will dedicate sufficient resources to meet our scheduled delivery requirements or that our suppliers will have sufficient resources to satisfy our requirements during any period of sustained demand. Failure of suppliers to supply, or delays in supplying, our raw materials or certain components, or allocations in the supply of certain high demand raw components, for any reason, including, without limitation, disruptions in our suppliers' business activities due to cybersecurity incidents, terrorist activity, public health crises (such as coronavirus), fires or other natural disasters could materially adversely affect our operations and ability to meet our own delivery schedules on a timely and competitive basis. Additionally, our third-party suppliers may provide us with raw materials or component parts that fail to meet our expectations or the expectations of our customers, which could subject us to product liability claims, other claims and litigation.

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Failure of third parties to manufacture quality products or provide reliable services in a timely manner could cause delays in developing, constructing, and operating our projects, which could damage our reputation, adversely affect our partner relationships or adversely affect our growth.

Our success depends on our ability to develop, construct, and operate projects in a timely manner, which depends in part on the ability of third parties to provide us with timely and reliable products and services. In developing, constructing, and operating our projects, we rely on products meeting our design specifications and components manufactured and supplied by third parties, and on services performed by subcontractors. We also rely on subcontractors to perform substantially all of manufacturing work related to our projects, and we may need to engage subcontractors with whom we have no experience.

We currently have a collaboration agreement in place with Zeeco. If Zeeco or any of our subcontractors are unable to provide services that meet or exceed our customers' expectations or satisfy our contractual commitments, our reputation, business and operating results could be harmed. In addition, if we are unable to avail ourselves of warranties and other contractual protections with providers of products and services, we may incur liability to our customers or additional costs related to the affected products and services, which could adversely affect our business, financial condition and results of operations. Moreover, any delays, malfunctions, inefficiencies or interruptions in these products or services could adversely affect the quality and performance of our projects and require considerable expense to find replacement products and to maintain and repair our projects. This could cause us to experience interruption in our production and distribution of our products, difficulty retaining current relationships and attracting new relationships, or harm our brand, reputation or growth. Additionally, because the Company's contracts generally include progress payments from customers upon the completion of certain defined milestones, the revenue recognition of such project will depend on our subcontractor's services in order for us to be able to achieve such milestones timely. Any subcontractor delays in fulfilling our contracts may result in delay of revenue recognition by the Company, which in turn can affect our financial condition and results of operations.

Macroeconomic pressures in the markets in which we operate may adversely affect our financial results.

Geopolitical issues around the world can impact macroeconomic conditions and could have a material adverse impact on our financial results. For example, the ultimate impact of the conflict in Ukraine, Israel and Strait of Hormuz on fuel prices, inflation, the global supply chain and other macroeconomic conditions is unknown and could materially adversely affect global economic growth, disrupting discretionary spending habits and generally decreasing demand for our products and services. While we do not purchase any of significant raw materials directly from these regions, they have significant global reach on commodity prices. Disruptions in the markets for those inputs could negatively impact the world and domestic economy. Also, these conflicts have exacerbated geopolitical tensions globally. While the demand of our services in the U.S. have not yet been affected by these conflicts, we cannot predict the impact that the conflicts may have on future financial results. For example, domestic customers for some of our product lines may choose to reduce discretionary spending on goods and services such as ours until this volatility subsides.

We are exposed to fluctuations in the market values of our investments and in interest rates, either of which could impair the market value of our investments and harm our financial results.

As of December 31, 2024, we had investments in short-term (i.e., less than three months) U.S. treasuries and money market accounts backed by U.S. treasuries. In the future, we may invest in long- or short-term U.S. treasuries or other marketable securities with maturities of up to one year. Currently, we do not use financial derivatives to hedge our interest rate exposure.

These investments, as well as any cash deposit in bank accounts, are subject to general credit, liquidity, market, inflation and interest rate risks, which may be exacerbated by unusual events, such as higher interest rates, potential recession and debates on the debt-ceiling, which may affect various sectors of the financial markets and lead to global economic slowdown and high inflation. If the global credit and capital market continues to experience volatility or deteriorates, and to the extent we make future investments, our investment portfolio may be impacted, and we could determine that some or all of our investments experienced an other-than-temporary decline in fair value, requiring impairment, which could adversely impact our financial position and operating results.

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Risks Related to Owning Our Securities

The public market for our securities is volatile. This may affect not only the ability of our investors to sell their securities, but the price at which they can sell their securities.

We completed the initial public offering of our common stock in April 2012. Since that time, our common stock (NASDAQ: CLIR) has traded as low as $0.35 per share and as high as $11.75 per share based upon daily closing prices, and day-to-day trading has been volatile at times. This volatility may continue or increase in the future. The market price for the securities may be significantly affected by factors such as progress in the development of our technology, agreements with research facilities or co-development partners, commercialization of our technology, variations in quarterly and yearly operating results, general trends in the alternative energy industry or clean technology industry, and changes in state or federal regulations affecting us and our industry. Furthermore, in recent years the stock market has experienced extreme price and volume fluctuations that are unrelated or disproportionate to the operating performance of the affected companies, such as the market reactions to internet marketed 'short squeezes'. Such broad market fluctuations may adversely affect the market price of our securities.

There may be future sales of our common stock, or a perception that these sales could occur, which events could cause the price of our common stock to decline.

Sales of a substantial number of shares of our common stock in the public market or the perception that such sales might occur could materially adversely affect the market price of the shares of our common stock. For instance, the securities issued in our recent equity offerings (see "Note 8 - Equity" for additional information), as well as the Warrant Shares, have been registered for resale and are freely tradable without restriction or further registration under the Securities Act. As a result, a substantial number of shares of common stock may be sold in the public market, subject to certain beneficial ownership restrictions. We cannot predict the effect, if any, that market sales of those shares of common stock or the availability of those shares for sale will have on the market price of our common stock.

We may be required to raise additional capital by issuing new securities, which may have terms or rights superior to those of our shares of common stock, which could adversely affect the market price of our shares of common stock and our business.

We will require additional financing to fund research, development and commercialization of our technology, to obtain and maintain patents and other intellectual property rights in our technology, and for working capital and other purposes. We may not be able to obtain financing on favorable terms, if at all. If we raise additional funds by issuing equity securities, the percentage ownership of our then-current stockholders will be reduced. Further, we may have to offer new investors in our equity securities rights that are superior to the holders of common stock, which could adversely affect the market price and the voting power of shares of our common stock. If we raise additional funds by issuing debt securities, the holders of these debt securities would similarly have some rights senior to those of the holders of shares of common stock, and the terms of these debt securities could impose restrictions on operations and create a significant interest expense for us which could have a materially adverse effect on our business and results of operations.

We will have broad discretion as to the proceeds that we receive from the cash exercise by any holder of our Warrants, and we may not use the proceeds effectively.

We may receive up to approximately $22.5 million in aggregate gross proceeds from cash exercises of our outstanding Warrants based on the per share exercise price of such Warrants, and to the extent that we receive such proceeds, we intend to use the net proceeds from cash exercises of the Warrants for working capital, research and development, marketing and sales, and general corporate purposes. We have considerable discretion in the application of such proceeds. You must rely on our judgment regarding the application of the net proceeds from cash exercises of the Warrants, which may be used for corporate purposes that do not improve our profitability or increase the price of our shares of common stock. Such proceeds may also be placed in investments that do not produce income or that lose value. The failure to use such funds by us effectively could have a material adverse effect on our business, financial condition, operating results and cash flow.

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You may experience future dilution as a result of issuance of the Warrant Shares, future equity offerings by us and other issuances of our common stock or other securities. In addition, the issuance of the Warrant Shares, to the extent the Warrants are exercisable, and future equity offerings and other issuances of our common stock or other securities may adversely affect our common stock price.

You may experience future dilution as a result of the issuance of the Warrant Shares and other issuances of our common stock or other securities. In order to raise additional capital, if needed, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share as prior issuances of common stock. We may not be able to sell shares or other securities in any other offering at a price per share that is equal to or greater than the price per share previously paid by investors, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock or securities convertible into common stock in future transactions may be higher or lower than the prices per share for previous issuances of common stock or securities convertible into common stock paid by certain investors. In addition, the exercise price of the Warrants may be equal to or greater than the price per share previously paid by certain investors. You will incur dilution upon exercise of any outstanding stock options, warrants or upon the issuance of shares of common stock under our equity incentive programs.

We have not paid dividends in the past and have no immediate plans to pay dividends.

We plan to reinvest all of our earnings, to the extent we have earnings, in order to continue to develop our products, to market our products, to cover operating costs and to otherwise become and remain competitive. We do not plan to pay any cash dividends with respect to our securities in the foreseeable future. We cannot assure you that we would, at any time, generate sufficient surplus cash that would be available for distribution to the holders of our common stock as a dividend.

We have a significant number of options and restricted stock units outstanding and we may issue additional awards in the future to employees, officers, directors, independent contractors and agents. Sales of the underlying shares of common stock could adversely affect the market price of our common stock.

As of December 31, 2024, we had outstanding options for the purchase of 2,943 thousand shares of common stock and 864 thousand shares of outstanding restricted stock units ("RSUs"). Under the ClearSign Technologies Corporation 2021 Equity Incentive Plan (the "2021 Plan") and the ClearSign Technologies Corporation 2013 Consultant Stock Plan (the "2013 Consultant Plan," and collectively, the "Plans"), we have the ability to grant awards of shares, RSU's or options to purchase shares of our common stock to employees, officers, directors, independent contractors and agents. Furthermore, the Plan provides for increases in the number of shares available for awards based on the terms outlined in such Plan. Certain holders may sell these shares in the public markets from time to time, without limitations on the timing, amount or method of sale. If our stock price rises, the holders may exercise their options and RSUs and sell a large number of shares. This could cause the market price of our common stock to decline.

We have the right to issue shares of preferred stock. If we were to issue preferred stock, it is likely to have rights, preferences and privileges that may adversely affect our common stock or other securities.

We are authorized to issue 2 million shares of "blank check" preferred stock, with such rights, preferences and privileges as may be determined from time-to-time by our board of directors (the "Board"). The Board is empowered, without stockholder approval, to issue preferred stock in one or more series, and to fix for any series the dividend rights, dissolution or liquidation preferences, redemption prices, conversion rights, voting rights, and other rights, preferences and privileges for the preferred stock. No shares of preferred stock are presently issued and outstanding and we have no immediate plans to issue shares of preferred stock. The issuance of shares of preferred stock, depending on the rights, preferences and privileges attributable to the preferred stock, could adversely reduce the voting rights and powers of the common stock and the portion of our assets allocated for distribution to common stockholders in a liquidation event, and could also result in dilution in the book value per share of our common stock. The preferred stock could also be utilized, under certain circumstances, as a method for raising additional capital or discouraging, delaying or preventing a change

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in control of the Company, to the detriment of our stockholders. We cannot assure you that we will not, under certain circumstances, issue shares of our preferred stock.

Our certificate of incorporation (as amended, the “certificate of incorporation”) provides that the Court of Chancery of the State of Delaware is the exclusive forum for certain disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our certificate of incorporation provides that, with certain limited exceptions, the Court of Chancery of the State of Delaware is the exclusive forum for:

- any derivative action or proceeding brought on our behalf;
- any action asserting a claim of breach of fiduciary duty owed by any director, officer or stockholder;
- any action asserting a claim against us arising under the Delaware General Corporation Law (“DGCL”), or as to which the DGCL confers jurisdiction on the Court of Chancery of the State of Delaware;
- any action arising pursuant to any provision of our bylaws or certificate of incorporation; and
- any action asserting a claim against us or any current or former director, officer or stockholder that is governed by the internal-affairs doctrine.

This provision does not apply to suits brought to enforce a duty or liability created by the Securities Act, the Exchange Act or any other claim for which the U.S. federal courts have exclusive jurisdiction. In addition, unless we consent in writing to the selection of an alternative forum, to the fullest extent permitted by law, the federal district courts of the United States of America shall be the exclusive forum for the resolution of any complaint asserting a cause or causes of action arising under the Securities Act, including all causes of action asserted against any defendant to such complaint.

For the avoidance of doubt, this provision is intended to benefit and may be enforced by us, our officers and directors, the underwriters to any offering giving rise to such complaint, and any other professional entity whose profession gives authority to a statement made by that person or entity and who has prepared or certified any part of the documents underlying the offering. However, these choice of forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, or other employees. Further, these choice of forum provisions may increase the costs for a stockholder to bring such a claim and may discourage them from doing so.

While the Delaware courts have determined that such choice of forum provisions are facially valid, a stockholder may nevertheless seek to bring a claim in a venue other than those designated in the exclusive forum provisions, and there can be no assurance that such provisions will be enforced by a court in those other jurisdictions. If a court were to find the choice of forum provision contained in our certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions. For example, the Court of Chancery of the State of Delaware recently determined that the exclusive forum provisions of federal district courts of the United States of America for resolving any complaint asserting a cause of action arising under the Securities Act is not enforceable. We note that investors cannot waive compliance with the federal securities laws and the rules and regulations thereunder.

The rights of our stockholders to take action against our directors and officers are limited.

Our certificate of incorporation provides for indemnification of our directors and officers to the fullest extent authorized or permitted under Delaware law, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL as the same exists or hereafter may be amended.

Our bylaws obligates us to indemnify each of our directors or officers who is or is threatened to be made a party to or witness in a proceeding by reason of his or her service in those or certain other capacities, to the maximum extent permitted by Delaware law, from and against any claim or liability to which such person may become subject or which such person may incur by reason of his or her status as a present or former director or officer of us or serving in such

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other capacities. In addition, we may be obligated to reimburse the expenses reasonably incurred by our present and former directors and officers in connection with such proceedings. As a result, we and our stockholders may have more limited rights to recover money damages from our directors and officers than might otherwise exist absent these provisions in our bylaws or that might exist with other companies, which could limit your recourse in the event of actions that are not in our best interests.

**We have incurred and will incur significant costs as a result of being a public company that reports to the Securities and Exchange Commission and our management is required to devote substantial time to meet compliance obligations.**

As a public company reporting to the Securities and Exchange Commission (the "SEC"), we incur significant legal, accounting, investor relations, printing, board compensation, and other expenses that we did not incur as a private company. These costs totaled $1.6 million in 2024. We are subject to the reporting requirements of the Exchange Act and the Sarbanes-Oxley Act of 2002 (with the exception of the requirement of auditor attestation of internal control over financial reporting from which we are currently excluded as a non-accelerated filer company), as well as rules subsequently implemented by the SEC that impose significant requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and changes in corporate governance practices. In addition, there are significant corporate governance and executive compensation-related provisions in the Dodd-Frank Wall Street Reform and Protection Act that as we grow could increase our legal and financial compliance costs, make some activities more difficult, time-consuming or costly and may also place undue strain on our personnel, systems and resources. Our management and other personnel continually devote a substantial amount of time to these compliance initiatives. Furthermore, these rules and regulations may make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain qualified people to serve on our Board, our Board committees or as executive officers.

**ITEM 1B. UNRESOLVED STAFF COMMENTS.**

None.

**ITEM 1C. CYBERSECURITY.**

We recognize the critical importance of developing, implementing, and maintaining robust cybersecurity measures to safeguard our information systems and protect the confidentiality, integrity, and availability of our data.

**Governance**

The audit and risk committee of our Board (the "Audit Committee") oversees risks related to cybersecurity, including the security of corporate information and the steps management takes to monitor and control these risks. Management regularly briefs the audit committee on our cybersecurity risk profile, potential threats, and continuous improvement initiatives. Our approach to managing cybersecurity risks is part of a continuous improvement process, both in the context of cybersecurity and broader operational risk management. This ongoing process, which includes employee training, is aimed at routinely reviewing and, as necessary, enhancing our oversight processes and tools to ensure they remain effective and resilient in their management of cybersecurity risk.

**Risk Management and Strategy**

We engage a third-party Managed Service Provider ("MSP") to implement technology infrastructure and oversee its tactical operations. Our MSP employs multiple people with experience in technical leadership, system architecture, network infrastructure and cybersecurity. We believe using an MSP provides economies of scale for a smaller-sized company such as ours, by allowing us access to a broad range of experience and tool sets that would otherwise be difficult to acquire in-house. Our MSP uses specialized third-party services and tool sets for identifying, protecting against, and detecting cyber incidents. Through these services and tools, our detection capabilities include, but

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are not limited to, near real-time monitoring, intrusion detection systems, and advanced analytics to identify abnormal patterns of behavior. These third-party detection tools provide near real-time alerts, log aggregation, and threat intelligence feeds.

In addition, we have engaged cybersecurity consultants, unaffiliated with our MSP, to advise management, assess our technology tools and review our cybersecurity practices. Our consultants utilized the National Institute of Standards and Technology (“NIST”) Cybersecurity Framework to assess our cybersecurity risk and governance practices. The NIST Cybersecurity Framework enables organizations, regardless of size, to apply principles and best practices of risk management to improve security and resilience.

## Material Impact of Cybersecurity Threats

While to date we are not aware of any material information security breaches and have not incurred significant operating expenses related to information security breaches, we acknowledge the persistent and evolving nature of these threats, which have the potential to materially impact our business strategy, operations, and financial standing adversely. See Item 1A, “Risk Factors” under the risks related to our business section for more information. Our incident response practices require incident assessments to be conducted in concert with our Chief Executive Officer, Chief Financial Officer and MSP. This enables faster response and effective communication, including public disclosure if a material cybersecurity event were to occur.

## ITEM 2. PROPERTIES.

Our principal office is located at 8023 East 63rd Place, Suite 101 Tulsa, Oklahoma 74133 with satellite offices located in Seattle and Beijing, China. At our principal office in Tulsa, we lease 3,922 square feet of office space, under a lease which expires in September 2027. Monthly minimum rent is approximately $5 thousand with an annual 2.0% increase. The Company also sub-leases 940 square feet of office space located in Seattle, Washington and 656 square feet in Beijing, China. The minimum monthly rent for our Seattle location is approximately $2 thousand with a termination date of September 30, 2025. The term of the Beijing lease began on June 1, 2024 and expires in June 2025. The monthly minimum rent for our Beijing location is approximately $3 thousand (20,000 RMB).

## ITEM 3. LEGAL PROCEEDINGS.

From time to time we may become involved in various lawsuits and legal proceedings which arise in the ordinary course of business. Litigation is subject to inherent uncertainties and an adverse result in any such matter may harm our business. As of the date of this report, we are not a party to any material pending legal proceedings.

## ITEM 4. MINE SAFETY DISCLOSURES.

Not applicable.

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# PART II

# ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES.

## Market Information for Common Stock

Our common stock is listed on the Nasdaq Capital Market under the symbol “CLIR”.

## Holders of Record

According to our transfer agent, as of March 21, 2025, we had 289 stockholders of record. This number does not include an indeterminate number of holders whose shares are held by brokers in street name. Our stock transfer agent is VStock Transfer, LLC, 18 Lafayette Place, Woodmere, NY 11598.

## Recent Issuances of Unregistered Securities

On December 31, 2024, we issued 3.8 thousand shares of common stock, having a weighted average per share value of $0.90 from our 2013 Consultant Plan to our investor relations firm, Firm IR Group LLC, for services provided in the three months ended December 31, 2024. We relied on Section 4(a)(2) of the Securities Act of 1933, as amended, and Regulation D promulgated thereunder to issue the stock.

## Equity Compensation Plan Information

See “Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters,” for information about our equity compensation plans.

## Dividend Policy

We have not paid any cash dividends on our common stock to date. The payment of cash dividends in the future is dependent upon our revenues and earnings, if any, capital requirements, the terms of any indebtedness and general financial condition. The payment of any cash dividends will be within the discretion of the board at such time. In addition, the board is not currently contemplating and does not anticipate declaring any stock dividends in the foreseeable future.

## Purchases of Equity Securities by the Issuer and Affiliated Purchasers

We had no share repurchase activity for the three months ended December 31, 2024.

# ITEM 6. [RESERVED]

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# ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with the audited consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. In addition to historical information, this discussion and analysis here and throughout this Form 10-K contains forward-looking statements that involve risks, uncertainties and assumptions. Our actual results may differ materially from those anticipated in these forward-looking statements due to a number of factors, including but not limited to, the risks described in the section titled "Risk Factors."

## Overview

We design and develop technologies for the purpose of decarbonization and improving key performance characteristics of industrial and commercial combustion systems, including emission and operational performance, energy efficiency and overall cost-effectiveness. Our ClearSign CoreTM technology has been proven in full scale industrial test furnaces and boilers and first customer installations are currently operating in normal commercial applications. Our revenues to date have not been sufficient enough to meet operating expenses.

We have incurred losses since inception totaling $99.0 million and we expect to experience operating losses and negative cash flow for the foreseeable future. We have historically financed our operations primarily through issuances of equity securities. As of December 31, 2024, we have raised approximately $105.3 million in gross proceeds through the sale of our equity securities. We may need to raise additional capital in the future, however, the significant volatility in the capital markets may negatively affect our ability to raise this additional capital.

In order to generate meaningful revenues, our technologies must gain market recognition and acceptance to develop sufficient recurring sales. In addition, management believes that the successful growth and operation of our business is dependent upon our ability to obtain adequate sources of funding through co-development agreements, strategic partnering agreements, or equity or debt financing to support commercialization of our research and development efforts, protect intellectual property, form relationships with strategic partners and provide for working capital and general corporate purposes. There can be no assurance that we will be successful in achieving our long-term plans, or that such plans, if consummated, will result in profitable operations or enable us to continue in the long-term as a going concern.

Our costs include employee salaries and benefits, compensation paid to consultants, materials and supplies for prototype development and manufacture, costs associated with development activities including materials, subcontractors, travel and administration, legal and accounting expenses, sales and marketing costs, general and administrative expenses, and other costs associated with an early stage, publicly traded technology company. We currently have 18 full-time employees. Because using third party expertise and resources is more efficient than maintaining full time resources, we also expect to incur ongoing consulting expenses related to technology development and some administrative, sales and legal functions commensurate with our current level of activities.

The amount that we spend for any specific purpose may vary significantly, and could depend on a number of factors including, but not limited to, the pace of progress of our commercialization and development efforts, actual needs with respect to product testing, development and research, market conditions, and changes in or revisions to our sales and marketing strategies.

Research, development, and commercial acceptance of new technologies are, by their nature, unpredictable. Although we undertake development and commercialization efforts with reasonable diligence, there can be no assurance that the net proceeds from our securities offerings will be sufficient to enable us to develop our technology to the extent needed to create sufficient future sales to sustain operations. If the net proceeds from these offerings are insufficient for this purpose, we will consider other options to continue our path to commercialization, including, but not limited to, additional financing through follow-on equity offerings, debt financing, co-development agreements, sale or licensing of developed intellectual or other property, or other alternatives.

We cannot assure that our technologies will be accepted, that we will ever earn revenues sufficient to support our operations, or that we will ever be profitable. Furthermore, we have no committed source of financing, and we cannot assure that we will be able to raise money as and when we need it to continue our operations. If we cannot raise funds as and when we need them, we may be required to scale back our development by reducing expenditures for employees, consultants, business development and marketing efforts or to otherwise severely curtail, or even to cease, our operations.

## Recent Developments

### Public Offering and Concurrent Private Placement

On April 23, 2024, we completed an underwritten public offering, whereby we sold 4,620,760 shares of common stock and 5-year redeemable warrants to purchase up to 4,620,760 shares of common stock (the “Public Warrants”) (plus a 45-day option to purchase up to an additional 693,114 shares of common stock and Public Warrants to purchase up to 693,114 shares of common stock, or up to 693,114 shares of common stock only) at a price of $0.92 per set of one share of common stock and one Public Warrant. Concurrently, we completed a private placement, whereby we sold 2,249,763 shares of common stock, pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 3,155,642 shares of common stock and redeemable warrants (the “Private Warrants”) to purchase up to 8,108,106 shares of common stock. The offering prices in the private placement were $0.91 per share and $0.01 per Private Warrant, or $0.9099 per Pre-Funded Warrant and $0.01 per Private Warrant, as applicable. The redeemable warrants issued in both offerings have an exercise price equal to $1.05 per share.

In connection with this offering, we issued Public Ventures, LLC (“Public Ventures”) 5-year warrants to purchase up to 369,660 shares of common stock at an exercise price of $1.1375 per share as part of their underwriter compensation, which underwriter warrants became exercisable on October 16, 2024 (the “Underwriter Warrants”). We also issued Public Ventures 5-year warrants to purchase up to 432,432 shares of common stock at an exercise price of $1.1375 per share as part of their placement agent compensation in connection with the private placement, which warrants became exercisable on October 16, 2024 (the “Placement Agent Warrants,” and together with the Public Warrants, Private Warrants, Pre-Funded Warrants and Underwriter Warrants, the “Warrants,” and the shares issuable upon exercise of the Warrants, the “Warrant Shares”). Both sets of warrants may be exercised on a cashless basis based on a formula set forth in the respective warrants.

Subsequently, on May 15, 2024, Public Ventures exercised its option in full to purchase an additional 693,114 shares of common stock and Public Warrants to purchase up to 693,114 shares of common stock at a price of $0.92 per set of one share of common stock and one Public Warrant, in connection with which we issued Public Ventures additional Underwriter Warrants to purchase up to 55,449 shares of common stock.

The public offering and the concurrent private placement resulted in combined gross proceeds of approximately $9,300 thousand, and net proceeds of approximately $8,100 thousand. The exercise of Public Ventures’ option to purchase additional shares of common stock and Public Warrants resulted in additional gross proceeds of approximately $638 thousand.

### Participation Right Exercise

On June 24, 2024, following clirSPV LLC’s (the “SPV”) notice to exercise its participation right in connection with the underwritten public offering and concurrent private placement discussed above (see “Note 8 - Equity” for additional information), we entered into a securities purchase agreement (the “Securities Purchase Agreement”) with the SPV whereby we issued an aggregate of (i) 3,907,000 shares of common stock, (ii) Pre-Funded Warrants to purchase up to 786,000 shares of common stock, and (iii) Private Warrants to purchase up to 7,039,500 shares of common stock.

Subsequently, on June 26, 2024, the SPV and we entered into an Amendment to the Securities Purchase Agreement (the “Amendment”) to provide for a revised allocation of the SPV’s subscription between shares of common stock and Pre-Funded Warrants in lieu thereof. Pursuant to the Amendment, the SPV subscribed for: (i) 3,350,000 shares of common stock, (ii) Pre-Funded Warrants to purchase up to 1,343,000 shares of common stock and (iii) Private

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Warrants to purchase up to 7,039,500 shares of common stock, for aggregate gross proceeds of approximately $4.3 million.

## Amendment to Certificate of Incorporation

On June 25, 2024, we held our 2024 annual meeting of stockholders, at which our stockholders approved, among other items, an increase in the number of authorized shares of common stock available for issuance under our certificate of incorporation to 87,500,000 shares from 62,500,000 shares previously authorized.

Accordingly, on June 25, 2024, we filed an amendment to our certificate of incorporation with the Secretary of State of the State of Delaware, reflecting the increase of our authorized shares of common stock to 87,500,000 shares, which became effective upon filing.

## Suspension of Activities in China

On October 1, 2024, we informed our employees that we were suspending our operations in China as a result of delayed progress in the commercialization of our products in that geographic market and as part of our efforts to align strategic priorities and to reduce operating costs. The suspension of our operations in China involved declaring our Beijing, China wholly-owned subsidiary dormant, a legal entity status available under current China law, which became effective on March 12, 2025. Under this legal entity status, operational activities will cease for a time period not to exceed three years. By pursuing this entity status, we initiated a project to suspend current operational activities. Suspension activities include disposal and shipment of certain equipment in China, the termination of 2 employees and related benefit costs, and legal entity filing fees. In connection with this action, we estimated that we would incur certain one-time costs, primarily consisting of employee termination payments, as well as equipment disposal and shipment and legal filing fees. See “Note 2 - Summary of Significant Accounting Policies - Foreign Operations” below for additional information.

## Termination of clirSPV LLC Agreement

Effective as of February 19, 2025, that certain Stock Purchase Agreement, dated as of July 12, 2018, between us and the SPV (the "SPV Purchase Agreement") was terminated as a result of the SPV's beneficial ownership percentage declining to less than 10% of our issued and outstanding shares of common stock, as reported on a SPV filing with the SEC dated February 19, 2025. As a result of the termination of the SPV Purchase Agreement, the related Voting Agreement entered into with the SPV, pursuant to which the SPV had a right to nominate one director to our Board at each of our annual meeting of stockholders, or any other meeting of stockholders at which members of our Board were to be elected, was also terminated, effective immediately.

## Critical Accounting Policies

The following discussion and analysis of financial condition and results of operations is based upon our consolidated financial statements, which have been prepared in conformity with accounting principles generally accepted in the United States of America. Certain accounting policies and estimates are particularly important to the understanding of our financial position and results of operations. These policies and estimates require the application of significant judgment by management. These estimates can be materially affected by changes from period to period as economic factors and conditions outside of our control change. As a result, they are subject to an inherent degree of uncertainty. In applying these policies, our management uses their judgment to determine the appropriate assumptions to be used in the determination of certain estimates. Those estimates are based on our historical operations, our future business plans and projected financial results, the terms of existing contracts, our observance of trends in the industry, information provided by our customers and information available from other outside sources, as appropriate. See "Note 2 - Summary of Significant Accounting Policies" to our consolidated financial statements included elsewhere in this report for a more complete description of our significant accounting policies.

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Revenue Recognition and Cost of Goods Sold.

The Company recognizes revenue and related cost of goods sold in accordance with Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers. Revenues and cost of goods sold are recognized once the goods or services are delivered to the customer's control or non-refundable performance obligations are satisfied. The Company's contracts with customers generally have performance obligations and a schedule of non-refundable cancellation obligations. The contracts generally will be fully performed upon delivery of certain documents or equipment. Revenue related to the contracts is recognized following the completion of non-refundable performance obligations as defined in the contract.

The Company's contracts generally include progress payments from customers upon completion of defined milestones. As these payments are received, they are offset against accumulated project costs and recorded as either contract assets or contract liabilities. Upon completion of the performance obligations and collectability is determined, revenue can be recorded. The Company records cost of goods sold based on allocated costs assigned to performance obligations. Allocations can occur based on overall estimated contract profit or readily identifiable cost assignments. For any contract in connection with which the Company is expected to incur costs in excess of the contact price, the Company accrues the estimated loss in full in the period such determination is made.

## Impairment of Long-Lived Assets

The Company tests long-lived assets, consisting of fixed assets, patents, and other intangible assets, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable through the estimated undiscounted cash flows expected from the use and eventual disposition of the assets. In the event an asset in not fully recoverable a loss is recognized based on the amount by which the carrying amount exceeds the fair value of the long-lived assets. Fair value is determined based on the present value of estimated expected cash flows using a discount rate commensurate with the risks involved, quoted market prices, or appraised values depending upon the nature of the assets. Losses on long-lived assets to be disposed of are determined in a similar manner, except those fair values are reduced for the cost of disposal.

## Product Warranties

The Company warrants all installed products against defects in materials and workmanship, and shortcomings in performance compared to contractual guarantees for a period specified in each contract. Accruals for product warranties are based on expected warranty experience and current product performance trends which are recorded as a component of cost of goods sold at the time revenue is recognized. The warranty liabilities are reduced by material and labor costs during the warranty period in the periods in which the costs are incurred. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary, and such adjustments could be material if estimates differ significantly from actual warranty expense. The warranty liabilities are included in accounts payable and accrued liabilities in the consolidated balance sheets.

## Research and Development

The cost of research and development is expensed as incurred. Research and development costs consist of salaries, benefits, share-based compensation, consumables, computer modeling costs and consulting fees, including costs to develop and test prototype equipment and parts. Research and development costs are offset by any funds received from strategic partners in cost sharing, collaborative projects. During the years ended December 31, 2024 and 2023, the Company received $145 thousand and $60 thousand, respectively, from such arrangements.

## Share-Based Compensation

The costs of all employee stock options, as well as other equity-based compensation arrangements, are reflected in the audited, condensed consolidated financial statements based on the estimated fair value of the awards on the grant date. That cost is recognized over the period during which an employee is required to provide service in exchange for the award, or in the case of performance options, expense is recognized upon completion of a milestone as defined in the

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grant agreement. Share-based compensation for stock grants to non-employees is determined as the fair value of the consideration received or the fair value of equity instruments issued, whichever is more reliably measured.

## Results of Operations

## Comparison of the Years Ended December 31, 2024 and 2023

Highlights of our annual financial performance are as follows:

| (in thousands, except per share data) | For the Year Ended December 31, |  |  |  |
| --- | --- | --- | --- | --- |
|  | 2024 | 2023 | $ Change | % Change |
| Revenues | $3,596 | $2,403 | $1,193 | 49.6% |
| Cost of goods sold | 2,478 | 1,586 | $892 | 56.2% |
| Gross profit | 1,118 | 817 | $301 | 36.8% |
| Research and development | 1,471 | 739 | $732 | 99.1% |
| General and administrative | 6,135 | 6,059 | $76 | 1.3% |
| Operating Expenses | 7,606 | 6,798 | $808 | 11.9% |
| Other income, net | 1,189 | 787 | $402 | 51.1% |
| Net loss | $(5,299) | $(5,194) | $(105) | (2.0)% |
| Basic and diluted net income per common share | $(0.11) | $(0.13) | $0.02 | 15.4% |

## Revenues and Gross Profit

Consolidated revenues for the years ended December 31, 2024 and 2023 were $3,596 thousand and $2,403 thousand, respectively. Revenues increased by $1,193 thousand, or 49.6%, during the year ended December 31, 2024 as compared to the same period in 2023. Revenues for the years ended December 31, 2024 and 2023 were generated from orders related to both our product lines, process burners and boiler burners, with the predominate amount of revenues generated from our process burner product line. Typically, our process burner contracts include three different performance obligations by which we can recognize revenue, which include design engineering, customer witness tests and burner shipment. We allocate process burner contractual revenue to each of these performance obligations with weighting allocations assigned in the following order of importance: burner shipment, customer witness test and engineering design. The difference in revenue from the year ended December 31, 2024, to the same period in 2023, is mainly due to the higher number of process burners shipped. During the year ended December 31, 2024, we shipped twenty-five process burners to two separate California refineries operated by two different customers, compared to eight process burners to a California refinery and three separate customer witness tests during the same period in 2023.

Gross profit increased by $301 thousand, or 36.8%, for the year ended December 31, 2024 compared to the same period in 2023. The favorable increase in gross profit for the year ended December 31, 2024, was predominantly due to higher revenues. Profit margin decreased by 2.9% from 34.0% for the year ended December 31, 2023, to 31.1% for the year ended December 31, 2024, which impacted our gross profit for such period by $104 thousand. The unfavorable impact to profit margin was due to higher than expected start-up costs from our 1,200 HP boiler burner project during the fourth quarter of 2024, which caused us to incur an overall loss on the project.

## Operating Expenses

Operating expenses consist of research and development ("R&amp;D") and general and administrative ("G&amp;A") expenses. These are addressed separately below.

## Research and Development

R&amp;D expenses increased $732 thousand, or 99.1%, for the year ended December 31, 2024, as compared to the same period in 2023. This unfavorable year-over-year increase in R&amp;D expenses was mainly driven by additional head

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count and related benefit costs of $269 thousand that did not exist in the same period in 2023. In addition, we incurred an unfavorable additional year-over-year expense related to product development costs for our process burner product line for a total of $367 thousand for the year ended December 31, 2024.

During the year ended December 31, 2023, we experienced a year-over-year unfavorable increase of $234 thousand primarily attributable to $83 thousand related to the hiring of our new Chief Technology Officer, and $60 thousand related to our hydrogen burner project. The hydrogen burner development project costs are offset by government assistance monies (see the "Other Income" discussion below for further details).

## General and Administrative

G&amp;A expenses increased $76 thousand, or 1.3%, for the year ended December 31, 2024, as compared to the same period in 2023. This unfavorable increase in G&amp;A expenses is primarily comprised of $394 thousand for a one-time non-recurring accrual estimate related to the decision to suspend our operations in China (see "Recent Developments - Suspension of Activities in China" above for more details). This suspension involved declaring our Beijing, China wholly-owned subsidiary dormant, which is a legal entity status available under China law. Under this legal entity status, operational activities cease for a period not to exceed three years. The unfavorable increase in G&amp;A expenses was partially offset by a decrease of $248 thousand in human capital costs primarily driven by the timing of employee departures and subsequent onboarding.

During the year ended December 31, 2023, we experienced a year-over-year unfavorable increase of $331 thousand primarily attributable to a $172 thousand difference for a non-cash, non-recurring expense related to the vesting of restricted stock units triggered by the departure of a director on our board, and a $81 thousand non-cash, non-recurring impairment of demonstration burners.

## Other Income

Other income increased by $402 thousand, or 51.1%, for the year ended December 31, 2024, as compared to the same period in 2023. The favorable increase is primarily attributable to $442 thousand increase in government assistance from our DOE hydrogen burner development grant, and $192 thousand increase in interest income from a higher cash balance during 2024, as compared to the same period in 2023. The favorable increase was partially offset by an unfavorable decrease of $197 thousand related to the decommissioning project of our Seattle office whereby we sold used equipment and materials during the year ended December 31, 2023.

During the year ended December 31, 2023, we experienced a favorable year-over-year increase of $428 thousand primarily attributable to an increase of $241 thousand in interest income and an increase of $197 thousand from our Seattle office decommissioning project.

## Liquidity and Capital Resources

At December 31, 2024, our cash and cash equivalents balance totaled $14,035 thousand compared to $5,684 thousand at December 31, 2023, an increase of $8,351 thousand. The increase in cash and cash equivalents is primarily attributable to our public offering and the concurrent private placement and the related SPV's exercise of its participation right during 2024 (see "Note 8 - Equity" for additional information), which was partially offset by our net loss of $5,299 thousand.

At December 31, 2024, our current assets were in excess of current liabilities resulting in working capital of $12,809 thousand as compared to $4,253 thousand at December 31, 2023. We believe we have sufficient cash and expected cash collections to fund current operating expenses for over twelve months. We have no contractual debt obligations and to the extent we may require additional funds beyond twelve months from the date hereof, and customer cash collections cannot fund our needs, we may utilize equity offerings. Historically, we have funded operations predominantly through equity offerings. Until the growth of revenue increases to a level that covers operating expenses, we intend to continue to fund operations in this manner, although the volatility in the capital markets may negatively affect our ability to do so. As of December 31, 2024, approximately 21.3 million shares of our common stock are

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issuable upon exercise of our outstanding warrants, which number excludes the shares of common stock issuable upon exercise of the Pre-Funded Warrants, and we may receive up to $22.5 million in aggregate gross proceeds from the cash exercises thereof, subject to certain beneficial ownership limitations set forth therein. The Warrants require the warrant holder to tender cash upon exercise, with the exception of the Underwriter Warrants (as defined above) which allow the holder to exercise cashless if they so desire. These equity financial instruments may from time-to-time fund future cash needs, but the volatility of our common stock price and the risk tolerance of warrant holders will determine the extent in which we will be able to raise funds in this manner.

Operating activities for the year ended December 31, 2024, resulted in cash outflows of $4,373 thousand, primarily due to the net loss of $5,299 thousand and a decrease in contract liabilities of $1,043 thousand during such period, which was partially offset by net non-cash expenses of $846 thousand, and an increase in accounts payable, accrued liabilities and lease liabilities of $816 thousand. The decision to suspend our China operations during the third quarter of 2024 continues to impact our accounts payable and accrued liabilities by an increase of $239 thousand during the year ended December 31, 2024. During the third quarter of 2024, we recorded a one-time accrual estimate of $394 thousand for the costs to prepare and place our Beijing, China subsidiary into a dormant state. As of December 31, 2024, we have incurred $155 thousand in cash outflows with the remaining $239 thousand in accrued liabilities predominantly related to severance costs. Our warranty reserve naturally increased due to increased product shipments during the year ended December 31, 2024, which impacted accounts payable and accrued liabilities (see “Note 6 - Product Warranties” below for additional information). The change in contract liabilities during the year ended December 31, 2024, was predominantly impacted by our shipment of process burners during the year ended December 31, 2024 (see “Note 5 - Revenue, Contract Assets and Contract Liabilities” below for additional information).

Operating activities for the year ended December 31, 2023 resulted in cash outflows of $3,233 thousand, primarily due to the loss for the period of $5,194 thousand, offset with non-cash expenses of $1,045 thousand, and an increase of $869 thousand of contract liabilities, which represents payments from customers in advance of future project costs.

Investing activities for the year ended December 31, 2024, resulted in cash outflows of $218 thousand, which is primarily attributable to $179 thousand of disbursements for patents and other intangible assets.

Investing activities for the year ended December 31, 2023 resulted in cash inflows of $2,490 thousand, which is primarily attributable to the redemption $4,847 thousand of short-term held-to-maturity U.S. treasuries, partially offset by $2,162 thousand of purchases for the same type of investments.

Financing activities for the year ended December 31, 2024, resulted in cash inflows of $12,946 thousand, which is primarily attributable to the net proceeds received of $12,967 thousand from the issuance of securities in connection with the recent equity offerings (see “Note 8 - Equity” for additional information).

Financing activities for the year ended December 31, 2023 included $15 thousand in disbursements for taxes paid related to vesting of employee restricted stock units.

## Off-Balance Sheet Transactions

We do not have any off-balance sheet transactions.

## ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

As a smaller reporting company, we are not required to provide this information.

## ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

Please see the financial statements beginning on page F-1 located in this report and incorporated herein by reference.

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# ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE.

None.

# ITEM 9A. CONTROLS AND PROCEDURES

## Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act that are designed to reasonably ensure that information required to be disclosed in our reports filed under the Exchange Act, is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our principal executive officer and principal accounting and financial officer, as appropriate, to allow timely decisions regarding required disclosure.

We carried out an evaluation under the supervision and with the participation of management, including our Chief Executive Officer (principal executive officer) and our Chief Financial Officer (principal accounting and financial officer), of the effectiveness of the design and operation of our disclosure controls and procedures as of December 31, 2024, the end of the period covered by this Annual Report on Form 10-K. Based upon the evaluation of our disclosure controls and procedures as of December 31, 2024, our Chief Executive Officer (principal executive officer) and our Chief Financial Officer (principal accounting and financial officer) concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

## Management’s Report on Internal Control over Financial Reporting

Our Chief Executive Officer (principal executive officer) and our Chief Financial Officer (principal accounting and financial officer) are responsible for establishing and maintaining internal control over financial reporting. Internal control over financial reporting is defined in Rule 13a-15(f) and 15d-15(f) promulgated under the Act as a process designed by, or under the supervision of, our principal executive and principal financial officers and effected by our Board, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and includes those policies and procedures that:

- pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of our assets;
- provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that our receipts and expenditures are being made only in accordance with authorizations of management and our directors; and
- provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of our assets that could have a material effect on the financial statements.

Because of its inherent limitations, our internal control over financial reporting may not prevent or detect misstatements. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation. Projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

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