Financial Data and Key Metrics Changes - For Q3 2025, the company recognized approximately $1 million in revenues, a decrease from approximately $1.9 million in Q3 2024, primarily due to a large order shipped in the prior year [5][6] - The net loss increased by approximately $274,000 compared to the same period in 2024, driven by the decrease in sales volume [7] - Gross margin increased by approximately 6.1 percentage points year-over-year for Q3 2025, reinforcing the long-term strategy to target margins between 40% and 45% [8] - Net cash used in operations for Q3 was approximately $1.8 million, compared to $1.4 million in the same period in 2024 [8] Business Line Data and Key Metrics Changes - Q3 2025 revenue was generated from multiple spare parts orders, a midstream order, a flare order, and engineering services, indicating a diversification strategy adding incremental revenue [6] - The M-series burners are targeted at the gas industry and midstream gas, with significant growth potential in the energy sector, particularly with export LNG [18][19] Market Data and Key Metrics Changes - There has been an uptick in order flow across major product lines, driven by regulatory pressures and increased customer inquiries, particularly in Texas and California [11][12] - The company is seeing increased interest in its products due to ongoing regulatory changes in key markets, which are pushing customers to meet compliance requirements [12][92] Company Strategy and Development Direction - The company aims to expand its market presence by getting more equipment out in the field and building customer trust [11] - The focus is on developing a range of burners capable of operating on various fuel types, including hydrogen, to meet future market demands [88] - The company is also looking to leverage its technology in larger systems projects, moving beyond just burner sales to include comprehensive solutions [62] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the future, highlighting the successful completion of significant projects and the potential for further orders [71] - The company anticipates continued traction in orders for the M-series and flare products, which are expected to fill revenue gaps while larger process burner orders are being developed [78] - Management does not foresee headwinds from federal regulatory changes, particularly regarding NOx emissions, and expects ongoing inquiries related to hydrogen capabilities [81][82] Other Important Information - The company has a strong working capital position, with approximately $10.5 million in cash and cash equivalents as of September 30, 2025 [8] - The relationship with Zeeco is strong, with extensive collaboration on testing and burner fabrication [70] Q&A Session Summary Question: What is the outlook for 2026 expected revenues based on the different types of orders? - Management indicated that while process burner orders are larger and take longer to execute, quicker-turn products like the M-series and flare orders will help fill revenue gaps [77][78] Question: Are there new product opportunities under development? - Management confirmed that there is potential for new products, particularly leveraging the technology developed under the SBIR program [80] Question: Is there any risk from federal regulatory changes affecting sales? - Management does not expect headwinds from the EPA regarding NOx emissions and sees ongoing interest in hydrogen capabilities from global clients [81][82] Question: What is the significance of spare parts in revenue? - Spare parts are becoming an increasingly important and consistent revenue stream, expected to grow as more equipment is installed [90][91] Question: What factors are driving increased orders from Texas and the Gulf Coast? - Management noted that while California business remains strong, there is a significant uptick in interest from the Gulf Coast due to regulatory awareness and acceptance in the industry [92]

Financial Data and Key Metrics Changes - For Q3 2025, the company recognized approximately $1 million in revenues, a decrease from approximately $1.9 million in Q3 2024, primarily due to a large order shipped in the prior year [5][6] - The net loss increased by approximately $274,000 compared to the same period in 2024, driven by the decrease in sales volume [6][8] - Gross margin increased by approximately 6.1 percentage points year-over-year for Q3 2025, reinforcing the long-term strategy to target margins between 40% and 45% [7] Business Line Data and Key Metrics Changes - Q3 2025 revenue was generated from multiple spare parts orders, a midstream order, a flare order, and engineering services, indicating a diversification strategy adding incremental revenue [6] - The M-series burners are targeted at the gas industry and midstream gas, with significant growth potential due to ongoing upgrades and compliance needs [18][19] Market Data and Key Metrics Changes - There has been an uptick in order flow across major product lines, driven by regulatory pressures and increased customer inquiries, particularly in Texas and California [11][12] - The company is seeing increased interest in its products due to evolving regulations in key markets, particularly regarding NOx emissions [17][62] Company Strategy and Development Direction - The company aims to expand its market presence by leveraging its technology to meet regulatory requirements and customer needs, particularly in the process burner and flare markets [12][62] - The development of a burner capable of operating on 100% hydrogen is seen as a significant opportunity for future applications, despite current market conditions [91] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the upcoming quarter, highlighting the shipment of 26 burners and ongoing projects that are expected to contribute to revenue [73][75] - The company anticipates that the M-series and flare products will help fill revenue gaps while larger process burner orders are being developed [80][82] Other Important Information - The company has approximately $10.5 million in cash and cash equivalents as of September 30, 2025, positioning it well for future growth [8] - Spare parts sales are expected to become a significant and consistent revenue stream as more equipment is installed [95] Q&A Session Summary Question: What is the impact of different order types on revenue expectations for 2026? - Management noted that process burner orders are larger but take longer to execute, while M-series and flare orders turn more quickly, helping to balance revenue flow [78][80] Question: Are there new product opportunities under development? - Management indicated potential for new products, particularly leveraging the technology developed under the SBIR program, which is versatile for various applications [83] Question: Is there any risk from federal regulatory changes affecting sales? - Management does not foresee significant headwinds from federal regulations, particularly regarding NOx emissions, and believes global interest in hydrogen capabilities will continue [84][92] Question: What is the outlook for spare parts revenue? - Spare parts are expected to grow as more equipment is installed, providing a high-margin revenue stream for the company [95] Question: What factors are driving increased orders from Texas and the Gulf Coast? - Management highlighted acceptance in the industry and upcoming regulatory changes as key factors driving interest in these regions [96]

As filed with the Securities and Exchange Commission on August 20, 2025 Registration No. 333-289549 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 1 TO FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 CLEARSIGN TECHNOLOGIES CORPORATION (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) (Primary Standard Industrial Delaware 3823 26-2056298 (I.R.S. Employer Identification No.) 8023 East 63 ...

As filed with the Securities and Exchange Commission on August 12, 2025 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 CLEARSIGN TECHNOLOGIES CORPORATION (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 3823 26-2056298 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identification No.) 8023 East ...

Financial Data and Key Metrics Changes - For Q1 2025, the company recognized approximately $400,000 in revenues, a decrease from $1,100,000 in the same period in 2024, primarily due to a decrease in process burner shipments [4][5] - The net loss increased by approximately $1,000,000 compared to Q1 2024, largely attributed to decreased sales volume and $581,000 in legal fees [5][6] - Net cash used in operations was approximately $1,100,000 for Q1 2025, compared to $1,000,000 in Q1 2024, with cash and cash equivalents at approximately $12,800,000 at the end of Q1 2025 [8] Business Line Data and Key Metrics Changes - The revenue decrease was driven by a shift from process burner shipments to spare parts orders [5] - The company has two significant process burner orders in different production stages, with installations expected in Q3 2025 [26][28] - A new product line, flare burners, has seen increased traction due to regulatory needs, with recent repeat orders from existing customers [13][18] Market Data and Key Metrics Changes - The number of quotations provided this year has doubled compared to the same period last year, with the total value of proposals nearly five times higher than last year [31][32] - The company is experiencing increased inquiries and interest in the midstream market, particularly for M1 burners [35] Company Strategy and Development Direction - The company is focusing on diversifying product lines and sales channels, with significant activities in engineering and customer interactions [11][12] - There is a strong emphasis on expanding sales channels through partnerships, such as with Zico, to enhance market reach [29][30] - The company is also exploring opportunities in the boiler burner market and enhancing the ClearSign Eye sensor product line [42][44] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the sales pipeline, noting that inquiries and proposals are increasing, indicating strong future business potential [31][32] - The company is closely monitoring regulatory changes and their impact on the market, particularly regarding NOx emissions and hydrogen technology [69][70] - Management highlighted the importance of upcoming installations and projects as key milestones for growth [56][57] Other Important Information - Legal fees incurred during the quarter were related to a regulatory inquiry and board activities concerning stockholder nominations [6][7] - The company is actively participating in key industry conferences to strengthen relationships and expand its network [38][39] Q&A Session Summary Question: How are Zico salespeople incentivized to sell or market your products? - Management indicated that the incentive system for Zico's sales team is still being worked out, but there is definitely an incentive structure in place [61][62] Question: Can additional sensors be deployed at the same location for ClearSign Eye? - Management confirmed that the refinery has many heaters, presenting thousands of potential opportunities for additional sensors [64] Question: How does the current tariff and regulatory environment affect the business? - Management noted minimal impact from tariffs and emphasized that the main driver remains the need for low NOx emissions, with no projects currently affected by tariff-related issues [66][69] Question: What is the competitive landscape for the increased proposal volume? - Management stated that the proposal growth is a mix of competitive situations and unique offerings, with ClearSign being recognized as a credible alternative to traditional solutions [78][80] Question: How much of the proposal volume is related to Zico? - Management clarified that currently, inquiries are primarily from the ClearSign team, with no contributions from Zico yet, indicating that Zico's impact will be additional to existing business [85]

Financial Data and Key Metrics Changes - For Q1 2025, the company recognized approximately $400,000 in revenues, a decrease from $1,100,000 in the same period in 2024, primarily due to a decrease in process burner shipments [5][6] - The net loss increased by approximately $1,000,000 compared to Q1 2024, attributed to decreased sales volume and $581,000 in legal fees [6][7] - Net cash used in operations was approximately $1,100,000 for Q1 2025, compared to $1,000,000 in Q1 2024, with cash and cash equivalents at approximately $12,800,000 at the end of Q1 2025 [8][9] Business Line Data and Key Metrics Changes - The revenue decrease was largely due to a shift from process burner shipments to spare parts orders [6] - The company has received a large order for 26 process burners for a Texas Gulf Coast chemical company, which is currently in testing [11][12] - A repeat order for flare products has been received, indicating a resurgence in this product line driven by regulatory needs [13][14] Market Data and Key Metrics Changes - The number of quotations provided this year has doubled compared to the same period last year, with the total value of proposals being just under five times that of the previous year [30][31] - The company is seeing increased interest in the midstream market, with repeat inquiries from established customers [35][36] Company Strategy and Development Direction - The company is focusing on diversifying product lines and sales channels, with ongoing efforts to engage with channel partners like Zico [28][36] - There is a strong emphasis on expanding the sales pipeline and leveraging relationships with major refineries to establish ClearSign as a credible alternative for emissions control solutions [40][78] - The company is also exploring opportunities in the hydrogen technology space while maintaining its focus on low NOx requirements [68][69] Management's Comments on Operating Environment and Future Outlook - Management expressed optimism about the future, citing strong interest in their products and the potential for increased inquiries and orders [30][31] - The company is closely monitoring the impact of tariffs and regulatory changes, noting minimal current effects on their operations [66][68] - Upcoming milestones include the startup of significant process burner projects and the engagement with Zico's sales team [55][56] Other Important Information - Legal fees incurred during the quarter were related to an SEC inquiry and stockholder director nominations, which are nearing completion [7] - The ClearSign Eye sensor product line is expected to see commercial traction in the next three to six months as installations begin [94] Q&A Session Summary Question: How are Zico salespeople incentivized to sell ClearSign products? - Management indicated that the incentive system is still being worked out, and discussions about specific incentives for ClearSign products have not yet occurred [61][62] Question: Can additional sensors be deployed at the same supermajor refinery? - Yes, the supermajor has many heaters with potential opportunities for additional sensors, and they have multiple refineries globally [64][65] Question: How does the current tariff and regulatory environment affect the business? - Management noted minimal impact from tariffs, with ongoing monitoring of regulatory changes, particularly regarding hydrogen technology [66][68] Question: What is the competitive landscape for the increased proposal volume? - The proposal growth includes competitive situations, but ClearSign is increasingly seen as a credible alternative to traditional solutions like SCR [77][78] Question: How much of the proposal volume is related to Zico? - Currently, inquiries are primarily from the ClearSign team, with no contributions from Zico yet, indicating that Zico's impact is still to come [82]