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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

☒ | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended

June 30, 2026

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: 001-33059

FUEL TECH, INC.

(Exact name of registrant as specified in its charter)

Delaware | 20-5657551
(State or other jurisdiction of incorporation of organization) | (I.R.S. Employer Identification Number)

Fuel Tech, Inc.

27601 Bella Vista Parkway

Warrenville, IL 60555-1617

630-845-4500

www.ftek.com

(Address and telephone number of principal executive offices)

________________________________

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 | FTEK | NASDAQ

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 |  | ☐ | Accelerated filer |  | ☐
Non-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 is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

On July 31, 2026 there were outstanding 31,216,789 shares of Common Stock, par value $0.01 per share, of the registrant.

Table of Contents

FUEL TECH, INC.

Form 10-Q for the six-month period ended June 30, 2026

INDEX

|  | Page
PART I. FINANCIAL INFORMATION |
Item 1. | Financial Statements (Unaudited) | 1
| Condensed Consolidated Balance Sheets as of June 30, 2026 and December 31, 2025 | 1
| Condensed Consolidated Statements of Operations for the Three and Six Months Ended June 30, 2026 and 2025 | 2
| Condensed Consolidated Statements of Comprehensive Income (Loss) for the Three and Six Months Ended June 30, 2026 and 2025 | 3
| Condensed Consolidated Statements of Stockholders' Equity for the Three and Six Months Ended June 30, 2026 and 2025 | 4
| Condensed Consolidated Statements of Cash Flows for the Six Months Ended June 30, 2026 and 2025 | 5
| Notes to Condensed Consolidated Financial Statements | 6
Item 2. | Management’s Discussion and Analysis of Financial Condition and Results of Operations | 15
Item 3. | Quantitative and Qualitative Disclosures about Market Risk | 17
Item 4. | Controls and Procedures | 17
PART II. | OTHER INFORMATION | 18
Item 1. | Legal Proceedings | 18
Item 1A. | Risk Factors | 18
Item 2. | Unregistered Sales of Equity Securities and Use of Proceeds | 18
Item 5. | Other Information | 18
Item 6. | Exhibits | 18
SIGNATURES | 19

Table of Contents

PART I. | FINANCIAL INFORMATION

Item 1. | Financial Statements

FUEL TECH, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(Unaudited)(in thousands, except share and per share data)

|  | June 30, |  |  | December 31, |
|  | 2026 |  |  | 2025 |
ASSETS |  |  |  |  |  |  |  |
Current assets: |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ | 7,620 |  |  | $ | 11,939 |
Short-term investments |  |  | 11,991 |  |  |  | 12,942 |
Accounts receivable, less current expected credit loss of $107 and $108, respectively |  |  | 3,904 |  |  |  | 5,355 |
Inventories, net |  |  | 358 |  |  |  | 373 |
Prepaid expenses and other current assets |  |  | 1,153 |  |  |  | 1,335 |
Total current assets |  |  | 25,026 |  |  |  | 31,944 |
Property and equipment, net of accumulated depreciation of $17,608 and $19,433, respectively |  |  | 4,782 |  |  |  | 4,739 |
Goodwill |  |  | 2,116 |  |  |  | 2,116 |
Other intangible assets, net of accumulated amortization of $604 and $561, respectively |  |  | 604 |  |  |  | 646 |
Right-of-use operating lease assets, net |  |  | 490 |  |  |  | 536 |
Long-term investments |  |  | 9,974 |  |  |  | 6,991 |
Other assets |  |  | 202 |  |  |  | 207 |
Total assets |  | $ | 43,194 |  |  | $ | 47,179 |
LIABILITIES AND STOCKHOLDERS' EQUITY |  |  |  |  |  |  |  |
Current liabilities: |  |  |  |  |  |  |  |
Accounts payable |  |  | 2,817 |  |  | $ | 3,242 |
Accrued liabilities: |  |  |  |  |  |  |  |
Operating lease liabilities - current |  |  | 94 |  |  |  | 89 |
Employee compensation |  |  | 718 |  |  |  | 1,308 |
Other accrued liabilities |  |  | 1,279 |  |  |  | 1,634 |
Total current liabilities |  |  | 4,908 |  |  |  | 6,273 |
Operating lease liabilities - non-current |  |  | 439 |  |  |  | 491 |
Deferred income taxes, net |  |  | 187 |  |  |  | 187 |
Other liabilities |  |  | 293 |  |  |  | 296 |
Total liabilities |  |  | 5,827 |  |  |  | 7,247 |
Stockholders’ equity: |  |  |  |  |  |  |  |
Common stock, $.01 par value, 40,000,000 shares authorized, 32,457,627 and 32,281,179 shares issued, and 31,216,789 and 31,074,438 shares outstanding, respectively |  |  | 324 |  |  |  | 322 |
Additional paid-in capital |  |  | 165,712 |  |  |  | 165,616 |
Accumulated deficit |  |  | (124,381 | ) |  |  | (121,796 | )
Accumulated other comprehensive loss |  |  | (1,751 | ) |  |  | (1,718 | )
Nil coupon perpetual loan notes |  |  | 76 |  |  |  | 76 |
Treasury stock, at cost |  |  | (2,613 | ) |  |  | (2,568 | )
Total stockholders’ equity |  |  | 37,367 |  |  |  | 39,932 |
Total liabilities and stockholders’ equity |  | $ | 43,194 |  |  | $ | 47,179 |

See notes to condensed consolidated financial statements.

1

Table of Contents

FUEL TECH, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(Unaudited)

(in thousands, except share and per-share data)

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Revenues |  | $ | 6,485 |  |  | $ | 5,558 |  |  | $ | 12,565 |  |  | $ | 11,940 |
Costs and expenses: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of sales |  |  | 3,810 |  |  |  | 3,029 |  |  |  | 7,246 |  |  |  | 6,452 |
Selling, general and administrative |  |  | 3,594 |  |  |  | 3,347 |  |  |  | 7,310 |  |  |  | 6,688 |
Research and development |  |  | 646 |  |  |  | 490 |  |  |  | 1,170 |  |  |  | 1,060 |
|  |  | 8,050 |  |  |  | 6,866 |  |  |  | 15,726 |  |  |  | 14,200 |
Operating loss |  |  | (1,565 | ) |  |  | (1,308 | ) |  |  | (3,161 | ) |  |  | (2,260 | )
Interest income |  |  | 266 |  |  |  | 537 |  |  |  | 506 |  |  |  | 816 |
Other income, net |  |  | 79 |  |  |  | 86 |  |  |  | 79 |  |  |  | 20 |
Loss before income taxes |  |  | (1,220 | ) |  |  | (685 | ) |  |  | (2,576 | ) |  |  | (1,424 | )
Income tax expense |  |  | (10 | ) |  |  | (4 | ) |  |  | (9 | ) |  |  | (4 | )
Net loss |  | $ | (1,230 | ) |  | $ | (689 | ) |  | $ | (2,585 | ) |  | $ | (1,428 | )
Net loss per common share: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic net loss per common share |  | $ | (0.04 | ) |  | $ | (0.02 | ) |  | $ | (0.08 | ) |  | $ | (0.05 | )
Diluted net loss per common share |  | $ | (0.04 | ) |  | $ | (0.02 | ) |  | $ | (0.08 | ) |  | $ | (0.05 | )
Weighted-average number of common shares outstanding: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic |  |  | 31,181,000 |  |  |  | 30,868,000 |  |  |  | 31,137,000 |  |  |  | 30,796,000 |
Diluted |  |  | 31,181,000 |  |  |  | 30,868,000 |  |  |  | 31,137,000 |  |  |  | 30,796,000 |

See notes to condensed consolidated financial statements.

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FUEL TECH, INC.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)

(Unaudited)

(in thousands)

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Net loss |  | $ | (1,230 | ) |  | $ | (689 | ) |  | $ | (2,585 | ) |  | $ | (1,428 | )
Other comprehensive income (loss): |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency translation adjustments |  |  | 10 |  |  |  | 11 |  |  |  | (33 | ) |  |  | 146 |
Comprehensive loss |  | $ | (1,220 | ) |  | $ | (678 | ) |  | $ | (2,618 | ) |  | $ | (1,282 | )

See notes to condensed consolidated financial statements.

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FUEL TECH, INC.

CONDENSED STATEMENTS OF STOCKHOLDERS’ EQUITY

(Unaudited)(in thousands of dollars or shares, as appropriate)

The following summarizes the changes in total stockholders' equity for the three and six months ended June 30, 2025:

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  | Nil |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  |  |  |  |  | Other |  |  | Coupon |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Accumulated |  |  | Comprehensive |  |  | Perpetual |  |  | Treasury |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Deficit |  |  | Loss |  |  | Loan Notes |  |  | Stock |  |  | Total |
Balance at December 31, 2024 |  |  | 30,708 |  |  | $ | 317 |  |  | $ | 165,295 |  |  | $ | (119,472 | ) |  | $ | (1,915 | ) |  | $ | 76 |  |  | $ | (2,346 | ) |  | $ | 41,955 |
Net loss |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (739 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (739 | )
Foreign currency translation adjustments |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 135 |  |  |  | — |  |  |  | — |  |  |  | 135 |
Stock compensation expense |  |  | — |  |  |  | — |  |  |  | 110 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 110 |
Common shares issued upon vesting of restricted stock units |  |  | 85 |  |  |  | 1 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 1 |
Taxes paid on behalf of equity award participants |  |  | (24 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (24 | ) |  |  | (24 | )
Balance at March 31, 2025 |  |  | 30,769 |  |  | $ | 318 |  |  | $ | 165,405 |  |  | $ | (120,211 | ) |  | $ | (1,780 | ) |  | $ | 76 |  |  | $ | (2,370 | ) |  | $ | 41,438 |
Net loss |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (689 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (689 | )
Foreign currency translation adjustments |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 11 |  |  |  | — |  |  |  | — |  |  |  | 11 |
Stock compensation expense |  |  | — |  |  |  | — |  |  |  | 102 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 102 |
Common shares issued upon vesting of restricted stock units |  |  | 429 |  |  |  | 4 |  |  |  | (4 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Taxes paid on behalf of equity award participants |  |  | (123 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (198 | ) |  |  | (198 | )
Balance at June 30, 2025 |  |  | 31,075 |  |  | $ | 322 |  |  | $ | 165,503 |  |  | $ | (120,900 | ) |  | $ | (1,769 | ) |  | $ | 76 |  |  | $ | (2,568 | ) |  | $ | 40,664 |

The following summarizes the changes in total stockholders' equity for the three and six months ended June 30, 2026:

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  | Nil |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  |  |  |  |  | Other |  |  | Coupon |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Accumulated |  |  | Comprehensive |  |  | Perpetual |  |  | Treasury |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Deficit |  |  | Loss |  |  | Loan Notes |  |  | Stock |  |  | Total |
Balance at December 31, 2025 |  |  | 31,074 |  |  | $ | 322 |  |  | $ | 165,616 |  |  | $ | (121,796 | ) |  | $ | (1,718 | ) |  | $ | 76 |  |  | $ | (2,568 | ) |  | $ | 39,932 |
Net loss |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (1,355 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (1,355 | )
Foreign currency translation adjustments |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (43 | ) |  |  | — |  |  |  | — |  |  |  | (43 | )
Stock compensation expense |  |  | — |  |  |  | — |  |  |  | 56 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 56 |
Common shares issued upon vesting of restricted stock units |  |  | 109 |  |  |  | 1 |  |  |  | (1 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Taxes paid on behalf of equity award participants |  |  | (26 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (34 | ) |  |  | (34 | )
Balance at March 31, 2026 |  |  | 31,157 |  |  | $ | 323 |  |  | $ | 165,671 |  |  | $ | (123,151 | ) |  | $ | (1,761 | ) |  | $ | 76 |  |  | $ | (2,602 | ) |  | $ | 38,556 |
Net loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (1,230 | ) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (1,230 | )
Foreign currency translation adjustments |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 10 |  |  |  | — |  |  |  | — |  |  |  | 10 |
Stock compensation expense |  |  | — |  |  |  | — |  |  |  | 42 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 42 |
Common shares issued upon vesting of restricted stock units |  |  | 68 |  |  |  | 1 |  |  |  | (1 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Taxes paid on behalf of equity award participants |  |  | (8 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (11 | ) |  |  | (11 | )
Balance at June 30, 2026 |  |  | 31,217 |  |  | $ | 324 |  |  | $ | 165,712 |  |  | $ | (124,381 | ) |  | $ | (1,751 | ) |  | $ | 76 |  |  | $ | (2,613 | ) |  | $ | 37,367 |

See notes to condensed consolidated financial statements.

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FUEL TECH, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

(in thousands)

|  | Six Months Ended |
|  | June 30, |
|  | 2026 |  |  | 2025 |
Operating Activities |  |  |  |  |  |  |  |
Net loss |  | $ | (2,585 | ) |  | $ | (1,428 | )
Adjustments to reconcile net loss to net cash (used in) provided by operating activities: |  |  |  |  |  |  |  |
Depreciation |  |  | 353 |  |  |  | 327 |
Amortization |  |  | 44 |  |  |  | 18 |
Interest income on held-to-maturity securities, net of premium amortization and discount accretion |  |  | 67 |  |  |  | (90 | )
Provision for credit losses, net of recoveries |  |  | (1 | ) |  |  | — |
Stock-based compensation, net of forfeitures |  |  | 98 |  |  |  | 212 |
Changes in operating assets and liabilities: |  |  |  |  |  |  |  |
Accounts receivable |  |  | 1,434 |  |  |  | 1,987 |
Employee retention credit receivable |  |  | — |  |  |  | 1,232 |
Inventory |  |  | 15 |  |  |  | (218 | )
Prepaid expenses, other current assets and other non-current assets |  |  | 182 |  |  |  | 77 |
Accounts payable |  |  | (417 | ) |  |  | (833 | )
Accrued liabilities and other non-current liabilities |  |  | (931 | ) |  |  | 203 |
Net cash (used in) provided by operating activities |  |  | (1,741 | ) |  |  | 1,487 |
Investing Activities |  |  |  |  |  |  |  |
Purchases of equipment and patents |  |  | (399 | ) |  |  | (101 | )
Purchases of debt securities |  |  | (9,103 | ) |  |  | (4,949 | )
Maturities of debt securities |  |  | 7,000 |  |  |  | 5,750 |
Net cash (used in) provided by investing activities |  |  | (2,502 | ) |  |  | 700 |
Financing Activities |  |  |  |  |  |  |  |
Taxes paid on behalf of equity award participants |  |  | (45 | ) |  |  | (222 | )
Net cash used in financing activities |  |  | (45 | ) |  |  | (222 | )
Effect of exchange rate fluctuations on cash |  |  | (31 | ) |  |  | 114 |
Net (decrease) increase in cash and cash equivalents |  |  | (4,319 | ) |  |  | 2,079 |
Cash and cash equivalents at beginning of period |  |  | 11,939 |  |  |  | 8,510 |
Cash and cash equivalents at end of period |  | $ | 7,620 |  |  | $ | 10,589 |

See notes to condensed consolidated financial statements.

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FUEL TECH, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

June 30, 2026

(Unaudited)

(in thousands, except share and per-share data)

1. General

Organization

Fuel Tech, Inc. and subsidiaries ("Fuel Tech", the "Company", "we", "us" or "our") develops and provides proprietary technologies for air pollution control, process optimization, water treatment, and advanced engineering services. These technologies enable customers to operate in a cost-effective and environmentally sustainable manner.

The Company’s nitrogen oxide (NOx) reduction technologies reduce nitrogen oxide emissions from boilers, furnaces, and other stationary combustion sources. To reduce NOx emissions, our technologies utilize advanced combustion modification techniques and post-combustion NOx control approaches including non-catalytic, catalytic, and combined systems. The Company also provides solutions for the mitigation of particulate matter, including particulate control with electrostatic precipitator products and services, and using flue gas conditioning systems which modify the ash properties of particulate for improved collection efficiency. The Company’s FUEL CHEM® technology improves the efficiency, reliability, fuel flexibility, boiler heat rate, and environmental status of combustion units by controlling slagging, fouling, corrosion, and opacity. Water treatment technologies include DGI® Dissolved Gas Infusion Systems which utilize a patented gas-infusing saturator vessel and a patent-pending channel injector to deliver supersaturated oxygen-water solutions and potentially other gas-liquid combinations to target process applications or environmental issues within the municipal and industrial water sectors. The infusion process has a variety of potential applications in the water and wastewater treatment sector, including aquaculture, agriculture/horticulture, pulp & paper, tanneries, landfill leachate, irrigation, treatment of natural waters, wastewater odor management as well as supplying oxygen or other gases for biochemical reactions and pH adjustment.

Many of Fuel Tech’s products and services rely heavily on the Company’s computational fluid dynamics modeling capabilities, which are enhanced by internally developed, high-end visualization software.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, the financial statements reflect all adjustments (consisting of normal recurring accruals) considered necessary for the fair statement of Fuel Tech's financial position, cash flows, and results of operations for the periods presented. All significant intercompany transactions and balances have been eliminated. The results of operations for the three and six months ended June 30, 2026 are not necessarily indicative of the results to be expected for the full year ending December 31, 2026. For further information, refer to the audited consolidated financial statements and footnotes thereto included in Fuel Tech’s Annual Report on Form 10-K for the year ended December 31, 2025 as filed with the Securities and Exchange Commission.

2. Summary of Significant Accounting Policies

Investments

The Company's investment policy provides for $20,000 in funds at BMO Harris Bank, N.A. (BMO Harris) to be invested in debt securities. The funds are held in money market funds until they are invested in those securities. A portion of the funds invested are restricted as collateral under the Investment Collateral Security agreement (see Note 10). At June 30, 2026, the amount of funds collateralized under the Investment Collateral Security agreement is $2,574 relating to existing standby letters of credit that is comprised of $2,250 with varying maturity dates that expire no later than June 30, 2027 and $324 with a latest maturity date of October 8, 2028.

We consider all highly liquid debt investments with original maturities from the date of purchase of three months or less as cash equivalents. Cash equivalents include investments in money market funds. Carrying value of cash equivalents approximates fair value due to the maturities of three months or less.

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Our investments in debt securities consist of United States (US) Treasury securities, including Notes, Bonds, and Bills, and US Government Agency securities, which are designated as held-to-maturity (HTM) and stated at amortized cost. The Company has the positive intent and ability to hold these investments to maturity and does not expect to sell any debt securities before maturity to settle an obligation under the Investment Collateral Security agreement. The original maturities of our HTM investments range from three to thirty-six months. HTM debt investments with original maturities of approximately three months or less from the date of purchase are classified within cash and cash equivalents. HTM debt investments with original maturities at the date of purchase greater than approximately three months and remaining maturities of less than one year are classified as short-term investments. HTM debt investments with remaining maturities beyond one year are classified as long-term investments. Interest income, including amortization of premium and accretion of discount, is included on the Condensed Consolidated Statements of Operations in Interest income under the effective yield method. Accrued interest is included in Prepaid expenses and other current assets on the Condensed Consolidated Balance Sheets. Due to the creditworthiness of the entities issuing these securities, there is no impairment recorded related to the unrealized losses.

The following table provides the amortized cost, gross unrealized gains and losses, and fair value of our HTM debt securities:

|  | As of |
Held-to-maturity debt securities: |  | June 30, 2026 |  |  | December 31, 2025 |
Amortized cost |  | $ | 21,965 |  |  | $ | 19,933 |
Gross unrecognized gains |  |  | 4 |  |  |  | 76 |
Gross unrecognized losses |  |  | (40 | ) |  |  | — |
Fair value |  | $ | 21,929 |  |  | $ | 20,009 |

The following table provides the amortized cost and fair value of debt securities by maturities at June 30, 2026:

|  | Amortized Cost |  |  | Fair Value |
Within one year |  | $ | 11,991 |  |  | $ | 11,979 |
After one year through two years |  |  | 9,974 |  |  |  | 9,950 |
Total |  | $ | 21,965 |  |  | $ | 21,929 |

Inventories

Inventories consist primarily of equipment constructed for resale and spare parts and are stated at the lower of cost or net realizable value, using the weighted-average cost method. At June 30, 2026 and December 31, 2025, inventory included equipment constructed for resale of $176 and spare parts, net of reserves, of $182 and $197, respectively. Usage is recorded in cost of sales in the period that parts were issued to a project, used to service equipment, or sold to customers. Equipment constructed for resale that is in process is recorded in Other assets. In process equipment for inventory recorded as Other assets was $52 and $53 as of June 30, 2026 and December 31, 2025, respectively. Inventories are periodically evaluated to identify obsolete or otherwise impaired parts and are written off when management determines usage is not probable. The Company estimates the balance of excess and obsolete inventory by analyzing inventory by age using the last used and original purchase dates and existing sales pipeline for which the inventory could be used.

Allowance for Credit Losses

The Company accounts for expected credit losses under Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) ASU 2019-10, Financial Instruments - Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842). This guidance requires the measurement of all expected losses based on historical experience, current conditions and reasonable and supportable forecasts. For trade receivables and other financial instruments, we are required to use a forward-looking expected loss model rather than the incurred loss model for recognizing credit losses which reflects losses that are probable.

For the general risk categories, the Company uses historical losses over a fixed period, excluding certain write-off activity that was not considered a credit loss event, to determine the historical credit loss. Historical loss rates are then adjusted to consider current economic conditions and past, current, and future events and circumstances when determining expected credit losses. Investments in financial assets issued by US Government and Government Agency are considered as having zero expected credit losses and are excluded from the allowance for credit loss calculation.

The following table provides the roll forward of the allowance for credit losses:

At January 1, 2025 |  | $ | 106 |
Provision charged to expense |  |  | — |
(Write-offs) / Recoveries |  |  | 2 |
At December 31, 2025 |  | $ | 108 |
Provision charged to expense |  |  | — |
(Write-offs) / Recoveries |  |  | (1 | )
At June 30, 2026 |  | $ | 107 |

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3. Revenue

Disaggregated Revenue by Product Technology

The following table presents our revenues disaggregated by product technology:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Air Pollution Control |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Technology solutions |  | $ | 2,078 |  |  | $ | 1,644 |  |  | $ | 2,833 |  |  | $ | 2,216 |
Spare parts |  |  | 417 |  |  |  | 425 |  |  |  | 811 |  |  |  | 675 |
Ancillary revenue |  |  | 290 |  |  |  | 436 |  |  |  | 745 |  |  |  | 917 |
Total Air Pollution Control technology revenues |  |  | 2,785 |  |  |  | 2,505 |  |  |  | 4,389 |  |  |  | 3,808 |
FUEL CHEM |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
FUEL CHEM technology solutions |  |  | 3,700 |  |  |  | 3,053 |  |  |  | 8,176 |  |  |  | 8,132 |
Total Revenues |  | $ | 6,485 |  |  | $ | 5,558 |  |  | $ | 12,565 |  |  | $ | 11,940 |

Disaggregated Revenue by Geography

The following table presents our revenues disaggregated by geography, based on the location of the end-user:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
United States |  | $ | 5,901 |  |  | $ | 4,442 |  |  | $ | 11,148 |  |  | $ | 9,801 |
Foreign Revenues |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Latin America |  |  | 189 |  |  |  | 65 |  |  |  | 375 |  |  |  | 413 |
Europe |  |  | 305 |  |  |  | 707 |  |  |  | 698 |  |  |  | 1,184 |
Africa |  |  | 14 |  |  |  | 156 |  |  |  | 14 |  |  |  | 194 |
Asia |  |  | 76 |  |  |  | 188 |  |  |  | 330 |  |  |  | 348 |
Total Foreign Revenues |  |  | 584 |  |  |  | 1,116 |  |  |  | 1,417 |  |  |  | 2,139 |
Total Revenues |  | $ | 6,485 |  |  | $ | 5,558 |  |  | $ | 12,565 |  |  | $ | 11,940 |

Timing of Revenue Recognition

The following table presents the timing of our revenue recognition:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Products transferred at a point in time |  | $ | 4,407 |  |  | $ | 3,914 |  |  | $ | 9,732 |  |  | $ | 9,724 |
Products and services transferred over time |  |  | 2,078 |  |  |  | 1,644 |  |  |  | 2,833 |  |  |  | 2,216 |
Total Revenues |  | $ | 6,485 |  |  | $ | 5,558 |  |  | $ | 12,565 |  |  | $ | 11,940 |

Contract Balances

The timing of revenue recognition, billings, and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the Condensed Consolidated Balance Sheets. In our Air Pollution Control (APC) technology segment, amounts are billed as work progresses in accordance with agreed-upon contractual terms. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. These assets are reported on the Condensed Consolidated Balance Sheets on a contract-by-contract basis at the end of each reporting period. At June 30, 2026, December 31, 2025, and December 31, 2024, contract assets for APC technology projects were approximately $1,223, $887, and $2,075, respectively, and are included in accounts receivable on the Condensed Consolidated Balance Sheets.

The Company will periodically bill in advance of costs incurred before revenue is recognized, resulting in contract liabilities. These liabilities are reported on the Condensed Consolidated Balance Sheets on a contract-by-contract basis at the end of each reporting period. Contract liabilities were $960, $1,026, and $721 at June 30, 2026, December 31, 2025, and December 31, 2024, respectively, and are included in other accrued liabilities on the Condensed Consolidated Balance Sheets.

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Changes in the contract asset and liability balances during the six-month period ended June 30, 2026 were not materially impacted by any other items other than amounts billed and revenue recognized as described previously. Revenue recognized that was included in the contract liability balance at the beginning of the period was $155 and $607 for the three and six months ended June 30, 2026, respectively, and $171 and $543 for the three and six months ended June 30, 2025, respectively, which represented revenue from progress towards completion of our APC technology contracts.

As of June 30, 2026 and December 31, 2025, we had no construction contracts in progress that were identified as a loss contract.

Remaining Performance Obligations

Remaining performance obligations represents the transaction price of APC technology booked orders for which work has not been performed. As of June 30, 2026, the aggregate amount of the transaction price allocated to remaining performance obligations was $14,308. The Company expects to recognize revenue on approximately $10,489 of the remaining performance obligations over the next 12 months with the remaining recognized thereafter.

Accounts Receivable

The components of accounts receivable are as follows:

|  | As of |
|  | June 30, 2026 |  |  | December 31, 2025 |
Trade receivables |  | $ | 2,690 |  |  | $ | 4,494 |
Unbilled receivables |  |  | 1,223 |  |  |  | 887 |
Other short-term receivables |  |  | 98 |  |  |  | 82 |
Allowance for credit losses |  |  | (107 | ) |  |  | (108 | )
Total accounts receivable |  | $ | 3,904 |  |  | $ | 5,355 |

4. Restructuring Activities

On January 18, 2019, the Company announced a planned suspension of its APC business operation in China. This action was part of Fuel Tech’s ongoing operational improvement initiatives designed to prioritize resource allocation, reduce costs, and drive profitability for the Company on a global basis. The transition associated with the suspension of the APC business which has taken place through June 30, 2026 includes staff rationalization and reduction, supplier and partner engagement, and the monetization of certain assets. The remaining transition activities include the execution of the activities to satisfy the requirements for the remaining APC projects in China (with a backlog totaling approximately $3) and those related to subsidiary closure.

The following table presents our revenues and net loss for the three and six months ended June 30, 2026 and 2025 in China as follows:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Total revenues |  | $ | 14 |  |  | $ | — |  |  | $ | 14 |  |  | $ | — |
Net loss |  |  | (9 | ) |  |  | (12 | ) |  |  | (22 | ) |  |  | (30 | )

The following table presents net assets in China as of June 30, 2026 and December 31, 2025:

|  | As of |
|  | June 30, 2026 |  |  | December 31, 2025 |
Total assets |  | $ | 768 |  |  | $ | 767 |
Total liabilities |  |  | 78 |  |  |  | 83 |
Total net assets |  | $ | 690 |  |  | $ | 684 |

Total assets primarily consist of cash and other receivables. Total liabilities consist of accounts payable and certain accrued liabilities.

5. Accumulated Other Comprehensive Loss

The changes in accumulated other comprehensive loss by component were as follows:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Foreign currency translation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at beginning of period |  | $ | (1,761 | ) |  | $ | (1,780 | ) |  | $ | (1,718 | ) |  | $ | (1,915 | )
Other comprehensive income (loss): |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Foreign currency translation adjustments (1) |  |  | 10 |  |  |  | 11 |  |  |  | (33 | ) |  |  | 146 |
Total accumulated other comprehensive loss |  | $ | (1,751 | ) |  | $ | (1,769 | ) |  | $ | (1,751 | ) |  | $ | (1,769 | )

(1) | In all periods presented, there were no tax impacts related to rate changes and no amounts were reclassified to earnings.

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6. Treasury Stock

Common stock held in treasury totaled 1,240,838 and 1,206,741 with a cost of $2,613 and $2,568 at June 30, 2026 and December 31, 2025, respectively. These shares were withheld from employees to settle personal tax withholding obligations that arose as a result of restricted stock units that vested.

7. Earnings per Share

Basic earnings per share excludes the dilutive effects of stock options, restricted stock units (RSUs), warrants, and the nil coupon non-redeemable convertible unsecured loan notes. Diluted earnings per share includes the dilutive effect of the nil coupon non-redeemable convertible unsecured loan notes, RSUs, warrants, and unexercised in-the-money stock options, except in periods of net loss where the effect of these instruments is anti-dilutive. Out-of-money stock options and warrants are excluded from diluted earnings per share because they are unlikely to be exercised and would be anti-dilutive if they were exercised. For the three and six months ended June 30, 2026 and 2025, basic earnings per share is equal to diluted earnings per share because all outstanding stock awards, warrants, and convertible loan notes are considered anti-dilutive during periods of net loss.

The following table sets forth the weighted-average shares used in calculating the earnings per share for the three and six months ended June 30, 2026 and 2025:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Basic weighted-average shares |  |  | 31,181,000 |  |  |  | 30,868,000 |  |  |  | 31,137,000 |  |  |  | 30,796,000 |
Unexercised options and unvested RSUs |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Diluted weighted-average shares |  |  | 31,181,000 |  |  |  | 30,868,000 |  |  |  | 31,137,000 |  |  |  | 30,796,000 |

For the three and six months ended June 30, 2026, Fuel Tech had weighted-average outstanding equity awards of 27,900 and 66,200, respectively, and warrants of 2,850,000 in both periods, which were antidilutive or represent out-of-the-money options for the purpose of the calculation of diluted earnings per share. For the three and six months ended June 30, 2026, Fuel Tech had incremental equity awards of 92,800 and 114,800, respectively, that were excluded from the computation of diluted earnings per share as the inclusion of such would have been anti-dilutive due to a net loss in the period. These equity awards could potentially dilute basic earnings per share in future years.

For the three and six months ended June 30, 2025, Fuel Tech had weighted-average outstanding equity awards of 36,800 and 71,300, respectively, and warrants of 2,850,000 in both periods, which were antidilutive or represent out-of-the-money options for the purpose of the calculation of diluted earnings per share. For the three and six months ended June 30, 2025, Fuel Tech had incremental equity awards of 316,100 and 467,100, respectively, that were excluded from the computation of diluted earnings per share as the inclusion of such would have been anti-dilutive due to a net loss in the period. These equity awards could potentially dilute basic earnings per share in future years.

8. Stock-Based Compensation

Fuel Tech's 2024 Long-Term Incentive Plan (2024 Plan) was adopted in June 2024 and replaced our prior incentive plan which was approved by our stockholders in 2014 (LTIP). No further grants will be made from the LTIP. The 2024 Plan and LTIP are referred to collectively as the Incentive Plans.

Under the Incentive Plans, awards may be granted to participants in the form of Non-Qualified Stock Options, Incentive Stock Options, Stock Appreciation Rights, Restricted Stock, RSUs, Performance Awards, Bonuses or other forms of share-based or non-share-based awards or combinations thereof. Participants in the Incentive Plans may be our directors, officers, employees, consultants, or advisors (except consultants or advisors in capital-raising transactions) as the directors determine are key to the success of our business. There are a maximum of 3,118,570 shares that may be issued or reserved for awards to participants under the Incentive Plans. As of June 30, 2026, Fuel Tech had 3,039,233 shares available for issuance under the Incentive Plans.

We did not record any excess tax benefits within income tax expense for the three and six months ended June 30, 2026 and 2025. Given the Company has a full valuation allowance on its deferred tax assets, there were no excess tax benefits to record for the three and six months ended June 30, 2026 and 2025. In addition, we account for forfeitures of awards based on an estimate of the number of awards expected to be forfeited and adjust the estimate when it is no longer probable that the employee will fulfill the service condition.

Stock-based compensation is included in selling, general, and administrative costs in our Condensed Consolidated Statements of Operations. The components of stock-based compensation for the three and six months ended June 30, 2026 and 2025 were as follows:

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Stock options and restricted stock units, net of forfeitures |  | $ | 42 |  |  | $ | 102 |  |  | $ | 98 |  |  | $ | 212 |
After-tax effect of stock-based compensation |  | $ | 42 |  |  | $ | 102 |  |  | $ | 98 |  |  | $ | 212 |

Stock Options

Stock options granted to employees under the Incentive Plans have a 10-year life and they vest as follows: 50% after the second anniversary of the award date, 25% after the third anniversary, and the final 25% after the fourth anniversary of the award date. Fuel Tech calculates stock compensation expense for employee option awards based on the grant date fair value of the award, less expected annual forfeitures, and recognizes expense on a straight-line basis over the four-year service period of the award. Stock options granted to members of our Board of Directors vest immediately. Stock compensation for these awards is based on the grant date fair value of the award and is recognized in expense immediately.

Fuel Tech uses the Black-Scholes option pricing model to estimate the grant date fair value of employee stock options. The principal variable assumptions utilized in valuing options and the methodology for estimating such model inputs include: (1) risk-free interest rate – an estimate based on the yield of zero–coupon treasury securities with a maturity equal to the expected life of the option; (2) expected volatility – an estimate based on the historical volatility of Fuel Tech’s Common Stock for a period equal to the expected life of the option; and (3) expected life of the option – an estimate based on historical experience including the effect of employee terminations.

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Stock option activity for Fuel Tech’s Incentive Plans for the six months ended June 30, 2026 was as follows:

|  |  |  |  |  |  |  |  |  | Weighted- Average |  |  |  |  |
|  | Number |  |  | Weighted- |  |  | Remaining |  |  | Aggregate |
|  | of |  |  | Average |  |  | Contractual |  |  | Intrinsic |
|  | Options |  |  | Exercise Price |  |  | Term |  |  | Value |
Outstanding on January 1, 2026 |  |  | 71,000 |  |  | $ | 1.20 |  |  |  |  |  |  |  |  |
Granted |  |  | — |  |  |  | — |  |  |  |  |  |  |  |  |
Exercised |  |  | — |  |  |  | — |  |  |  |  |  |  |  |  |
Expired or forfeited |  |  | (27,000 | ) |  |  | 1.58 |  |  |  |  |  |  |  |  |
Outstanding on June 30, 2026 |  |  | 44,000 |  |  | $ | 0.96 |  |  |  | 1.44 |  |  | $ | 55 |
Exercisable on June 30, 2026 |  |  | 44,000 |  |  | $ | 0.96 |  |  |  | 1.44 |  |  | $ | 55 |

As of June 30, 2026, there was no unrecognized compensation cost related to non-vested stock options granted under the Incentive Plans.

Restricted Stock Units

RSUs granted to employees vest over time based on continued service (typically vesting over a period between two to four years), and RSUs granted to directors vest after a one year vesting period based on continued service. Such time-vested RSUs are valued at the date of grant based on the closing price of the Common Shares on the grant date. Compensation cost, adjusted for estimated forfeitures, is amortized on a straight-line basis over the requisite service period.

In addition to the time vested RSUs, in 2025 the Company entered into an Executive Performance RSU Award Agreement (the “Agreement”) with certain officers, including its President and Chief Executive Officer, Chief Financial Officer and Senior Vice President, Sales (each a “Participating Executive”) pursuant to which each Participating Executive will have the opportunity to earn a specified amount of restricted stock units (RSUs) based on Fuel Tech’s performance in 2026. The target amount of RSUs for each of four possible RSU award components is set for each Participating Executive for 2026. The amount of actual RSU awards to be issued is contingent on performance by the Participating Executive and the Company in the performance areas and for the measurement periods set forth in the Agreement as determined by the Company.

The Agreement provides for four possible RSU awards: “Look-Back RSUs,” “Total Revenue RSUs,” “New Business Revenue RSUs,” and “Operating Income” RSUs. If the Look-Back RSU’s are awarded, these RSUs will follow a vesting schedule that provides for vesting of one-third of the granted Look-Back RSUs after the first anniversary of the grant determination date, one-third after the second anniversary date and one-third after the third anniversary date. If the Total Revenue RSUs, New Business Revenue RSUs, or Operating Income RSUs targets are achieved, these RSU’s will follow a vesting schedule whereby 100% of the granted RSUs will vest one year following the grant determination date. All RSUs are valued at the date of grant based on the closing price of the Company’s common stock on the grant date.

At June 30, 2026, there is $632 of unrecognized compensation cost related to all non-vested share-based compensation arrangements granted under the Incentive Plan. That cost is expected to be recognized over the remaining requisite service period of 1.75 years.

A summary of restricted stock unit activity for the six months ended June 30, 2026 is as follows:

|  |  |  |  |  | Weighted Average |
|  |  |  |  |  | Grant Date |
|  | Shares |  |  | Fair Value |
Unvested restricted stock units at January 1, 2026 |  |  | 1,109,222 |  |  | $ | 1.06 |
Granted |  |  | 115,850 |  |  |  | 1.33 |
Vested |  |  | (176,449 | ) |  |  | 1.29 |
Forfeited |  |  | (425,100 | ) |  |  | 1.02 |
Unvested restricted stock units at June 30, 2026 |  |  | 623,523 |  |  | $ | 1.08 |

The fair value of restricted stock that vested during the six-month period ended June 30, 2026 was $228.

Deferred Directors Fees

In addition to the Incentive Plans, Fuel Tech has a Deferred Compensation Plan for Directors (Deferred Plan). Under the terms of the Deferred Plan, Directors can elect to defer Directors’ fees for shares of Fuel Tech Common Stock that are issuable at a future date as defined in the agreement. In accordance with Accounting Standards Codification (ASC) 718, Fuel Tech accounts for these awards as equity awards as opposed to liability awards. During the six-month periods ended June 30, 2026 and 2025, Fuel Tech recorded no stock-based compensation expense under the Deferred Plan.

9. Warrants

The following table summarizes information about warrants outstanding and exercisable at June 30, 2026:

Exercise Price |  |  | Number Outstanding/Exercisable |  |  | Weighted Average Remaining Life in Years |  |  | Weighted Average Exercise Price |
$5.10 |  |  |  | 2,500,000 |  |  | 0.12 |  |  | $ | 5.10 |
$6.45 |  |  |  | 350,000 |  |  | 0.12 |  |  | $ | 6.45 |
|  |  |  | 2,850,000 |  |  |  |  |  |  |  |

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10. Debt Financing

The Company's Investment Collateral Security Agreement with BMO Harris is used for the sole purpose of issuing standby letters of credit and requires us to pledge our investments as collateral for 150% of the aggregate face amount of outstanding standby letters of credit. The Company pays 250 basis points on the face values of outstanding letters of credit. There are no financial covenants set forth in the Investment Collateral Security agreement. At June 30, 2026, the Company had outstanding standby letters of credit totaling approximately $1,716 under the Investment Collateral Security agreement. At June 30, 2026, the investments held as collateral totaled $2,574. Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments.

11. Business Segment and Geographic Financial Data

Business Segment Financial Data

We segregate our financial results into two reportable segments representing two broad technology segments as follows:

| • | The Air Pollution Control technology segment includes technologies to reduce NOx emissions in flue gas generated by the firing of natural gas or coal from boilers, incinerators, furnaces, and other stationary combustion sources. These include Over-Fire Air systems, NOxOUT® and HERT™ Selective Non-Catalytic Reduction systems, and Selective Catalytic Reduction (SCR) systems. Our SCR systems can also include Ammonia Injection Grid, and Graduated Straightening Grid GSG™ systems to provide high NOx reductions at significantly lower capital and operating costs than conventional SCR systems. ULTRA® technology creates ammonia at a plant site using safe urea for use with any SCR application. Electrostatic Precipitator (ESP) technologies make use of electrostatic precipitator products and services to reduce particulate matter. Flue Gas Conditioning systems are chemical injection systems offered in markets outside the U.S. and Canada to enhance electrostatic precipitator and fabric filter performance in controlling particulate emissions.

| • | The FUEL CHEM® technology segment, which uses chemical processes in combination with advanced Computational Fluid Dynamics and Chemical Kinetics Modeling boiler modeling, for the control of slagging, fouling, corrosion, opacity and other sulfur trioxide-related issues in furnaces and boilers through the addition of chemicals into the furnace using TIFI® Targeted In-Furnace Injection™ technology.

The “Other” classification includes those profit and loss items not allocated to either reportable segment. There are no inter-segment sales that require elimination.

Our Chief Executive Officer (CEO) serves as our Chief Operating Decision Maker (CODM) and is responsible for reviewing segment performance and making decisions regarding resource allocation. We evaluate performance and allocate resources based on reviewing gross margin by reportable segment. We do not allocate selling, general and administrative expenses, interest, other non-operating income or expense items, or taxes to segments. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies (Note 1 in our annual report on Form 10-K). We do not review assets by reportable segment, but rather, in aggregate for the Company as a whole.

Information about reporting segment net sales and gross margin from continuing operations is provided below:

|  | Air Pollution |  |  | FUEL CHEM |  |  |  |  |  |  |  |  |
Three months ended June 30, 2026 |  | Control Segment |  |  | Segment |  |  | Other |  |  | Total |
Revenues from external customers |  | $ | 2,785 |  |  | $ | 3,700 |  |  | $ | — |  |  | $ | 6,485 |
Cost of sales |  |  | (1,775 | ) |  |  | (2,035 | ) |  |  | — |  |  |  | (3,810 | )
Gross margin |  |  | 1,010 |  |  |  | 1,665 |  |  |  | — |  |  |  | 2,675 |
Selling, general and administrative |  |  | — |  |  |  | — |  |  |  | (3,594 | ) |  |  | (3,594 | )
Research and development |  |  | — |  |  |  | — |  |  |  | (646 | ) |  |  | (646 | )
Income (loss) from operations |  | $ | 1,010 |  |  | $ | 1,665 |  |  | $ | (4,240 | ) |  | $ | (1,565 | )

|  | Air Pollution |  |  | FUEL CHEM |  |  |  |  |  |  |  |  |
Three months ended June 30, 2025 |  | Control Segment |  |  | Segment |  |  | Other |  |  | Total |
Revenues from external customers |  | $ | 2,505 |  |  | $ | 3,053 |  |  | $ | — |  |  | $ | 5,558 |
Cost of sales |  |  | (1,406 | ) |  |  | (1,623 | ) |  |  | — |  |  |  | (3,029 | )
Gross margin |  |  | 1,099 |  |  |  | 1,430 |  |  |  | — |  |  |  | 2,529 |
Selling, general and administrative |  |  | — |  |  |  | — |  |  |  | (3,347 | ) |  |  | (3,347 | )
Research and development |  |  | — |  |  |  | — |  |  |  | (490 | ) |  |  | (490 | )
Income (loss) from operations |  | $ | 1,099 |  |  | $ | 1,430 |  |  | $ | (3,837 | ) |  | $ | (1,308 | )

|  | Air Pollution |  |  | FUEL CHEM |  |  |  |  |  |  |  |  |
Six months ended June 30, 2026 |  | Control Segment |  |  | Segment |  |  | Other |  |  | Total |
Revenues from external customers |  | $ | 4,389 |  |  | $ | 8,176 |  |  | $ | — |  |  | $ | 12,565 |
Cost of sales |  |  | (2,764 | ) |  |  | (4,482 | ) |  |  | — |  |  |  | (7,246 | )
Gross margin |  |  | 1,625 |  |  |  | 3,694 |  |  |  | — |  |  |  | 5,319 |
Selling, general and administrative |  |  | — |  |  |  | — |  |  |  | (7,310 | ) |  |  | (7,310 | )
Research and development |  |  | — |  |  |  | — |  |  |  | (1,170 | ) |  |  | (1,170 | )
Income (loss) from operations |  | $ | 1,625 |  |  | $ | 3,694 |  |  | $ | (8,480 | ) |  | $ | (3,161 | )

|  | Air Pollution |  |  | FUEL CHEM |  |  |  |  |  |  |  |  |
Six months ended June 30, 2025 |  | Control Segment |  |  | Segment |  |  | Other |  |  | Total |
Revenues from external customers |  | $ | 3,808 |  |  | $ | 8,132 |  |  | $ | — |  |  | $ | 11,940 |
Cost of sales |  |  | (2,284 | ) |  |  | (4,168 | ) |  |  | — |  |  |  | (6,452 | )
Gross margin |  |  | 1,524 |  |  |  | 3,964 |  |  |  | — |  |  |  | 5,488 |
Selling, general and administrative |  |  | — |  |  |  | — |  |  |  | (6,688 | ) |  |  | (6,688 | )
Research and development |  |  | — |  |  |  | — |  |  |  | (1,060 | ) |  |  | (1,060 | )
Income (loss) from operations |  | $ | 1,524 |  |  | $ | 3,964 |  |  | $ | (7,748 | ) |  | $ | (2,260 | )

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Geographic Segment Financial Data

Information concerning our operations by geographic area is provided below. Revenues are attributed to countries based on the location of the end-user. Assets are those directly associated with operations of the geographic area.

|  | Three Months Ended |  |  | Six Months Ended |
|  | June 30, |  |  | June 30, |
|  | 2026 |  |  | 2025 |  |  | 2026 |  |  | 2025 |
Revenues: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
United States |  | $ | 5,901 |  |  | $ | 4,442 |  |  | $ | 11,148 |  |  | $ | 9,801 |
Foreign |  |  | 584 |  |  |  | 1,116 |  |  |  | 1,417 |  |  |  | 2,139 |
|  | $ | 6,485 |  |  | $ | 5,558 |  |  | $ | 12,565 |  |  | $ | 11,940 |

|  | June 30, |  |  | December 31, |
|  | 2026 |  |  | 2025 |
Assets: |  |  |  |  |  |  |  |
United States |  | $ | 40,636 |  |  | $ | 44,345 |
Foreign |  |  | 2,558 |  |  |  | 2,834 |
|  | $ | 43,194 |  |  | $ | 47,179 |

12. Accrued Liabilities

The components of other accrued liabilities are as follows:

|  | As of |
|  | June 30, 2026 |  |  | December 31, 2025 |
Contract liabilities (Note 3) |  | $ | 960 |  |  | $ | 1,026 |
Warranty reserve (Note 13) |  |  | 159 |  |  |  | 159 |
Deferred revenue |  |  | 89 |  |  |  | 91 |
Accrued professional fees |  |  | — |  |  |  | 83 |
Other accrued liabilities |  |  | 71 |  |  |  | 275 |
Total other accrued liabilities |  | $ | 1,279 |  |  | $ | 1,634 |

13. Commitments and Contingencies

Fuel Tech is subject to various claims and contingencies related to, among other things, workers compensation, general liability (including product liability), and lawsuits. The Company records liabilities where a contingent loss is probable and can be reasonably estimated. If the reasonable estimate of a probable loss is a range, the Company records the most probable estimate of the loss or the minimum amount when no amount within the range is a better estimate than any other amount. The Company discloses a contingent liability even if the liability is not probable or the amount is not estimable, or both, if there is a reasonable possibility that a material loss may have been incurred.

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From time to time we are involved in litigation with respect to matters arising from the ordinary conduct of our business. In the opinion of management, based upon presently available information, either adequate provision for anticipated costs have been accrued or the ultimate anticipated costs will not materially affect our consolidated financial position, results of operations, or cash flows. We do not believe we have any pending loss contingencies that are probable or reasonably possible of having a material impact on our consolidated financial position, results of operations or cash flows.

Fuel Tech issues a standard product warranty with the sale of its products to customers. Our recognition of warranty liability is based primarily on analyses of warranty claims experienced in the preceding years as the nature of our historical product sales for which we offer a warranty are substantially unchanged. This approach provides an aggregate warranty accrual that is historically aligned with actual warranty claims experienced.

There was no change in the warranty liability balance included in the other accrued liabilities line of the Condensed Consolidated Balance Sheets during the six months ended June 30, 2026 and 2025. The warranty liability balance was $159 at June 30, 2026 and December 31, 2025.

14. Income Taxes

The Company’s effective tax rate is approximately 0.3% and 0.3% for the six-month periods ended June 30, 2026 and 2025, respectively. The Company's effective tax rate differs from the statutory federal tax rate of 21% for the six-month periods ended June 30, 2026 and 2025 primarily due to a full valuation allowance recorded on our United States, China and Italy deferred tax assets since we cannot anticipate when or if we will have sufficient taxable income to utilize the deferred tax assets in the future. Further, our effective tax rate differs from the statutory federal tax rate due to state taxes, differences between U.S. and foreign tax rates, foreign losses incurred with no related tax benefit, non-deductible commissions, and non-deductible meals and entertainment expenses for the six-month periods ended June 30, 2026 and 2025.

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FUEL TECH, INC.

Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations

Overview

During the quarter, the Company delivered revenue growth in both reportable segments, reflecting improved demand in FUEL CHEM and continued execution in Air Pollution Control. The FUEL CHEM segment benefited from higher activity levels at legacy customer accounts, while the Air Pollution Control segment revenue increased as the Company advanced existing projects and continued to pursue and secure new contract awards.

Management believes the Company’s operating performance and Air Pollution Control backlog provide improved revenue visibility, while business development activity continues to reflect market interest in emissions-control solutions across multiple fuel sources. The Company is also investing in new technologies intended to broaden its addressable market, including potential applications in the water and wastewater treatment market.

The Company believes its existing capital resources are sufficient to support current operations, planned technology development, and reasonably anticipated operating requirements. Management remains focused on disciplined cost control while pursuing opportunities that could support improved financial performance, market position, and long-term shareholder value.

The Company’s future results will depend in part on the level of activity from legacy FUEL CHEM customers, the timing and conversion of Air Pollution Control backlog and new contract awards, the pace of technology development and commercialization, and the Company’s ability to manage costs while supporting growth initiatives.

Key Operating Factors

The Company’s FUEL CHEM segment generated higher revenue in the current quarter compared to the corresponding 2025 period, while segment operating profit decreased slightly. The increase in revenue was primarily attributable to higher operating activity from the segment’s existing customer base.

The Company’s Air Pollution Control segment also generated higher revenue in the current quarter compared to the corresponding 2025 period, primarily due to the timing of project execution and increased ancillary revenue. The Company continues to execute on existing Air Pollution Control projects while pursuing and booking new contract awards.

Management is encouraged by the depth of the Company's business development activities, which reflects increased market attention to global emissions protocols across a variety of fuel sources. Consolidated APC backlog at June 30, 2026 was $14,308 and the Company's global sales pipeline was approximately $75 -100 million.

Results of Operations

Revenues

Revenues for the three-month periods ending June 30, 2026 and 2025 were $6,485 and $5,558, respectively, representing an increase of $927, or 17%, versus the same period last year. Revenues for the six-month periods ending June 30, 2026 and June 30, 2025 were $12,565 and $11,940, representing an increase of $625, or 5%, versus the same period last year.

The APC technology segment generated revenues of $2,785 for the three-month period ended June 30, 2026, representing an increase of $280, or 11%, from the prior year amount of $2,505.The APC technology segment generated revenues of $4,389 for the six-month period ended June 30, 2026, representing an increase of $581, or 15%, from the prior year amount of $3,808. The increase was primarily attributable to the timing of project execution on existing contracts and increased consolidated segment backlog resulting from new project awards. Consolidated APC backlog at June 30, 2026 was $14,308 versus backlog at December 31, 2025 of $7,047. Our current backlog consists of U.S. domestic delivered projects totaling $11,262 and international delivered projects totaling $3,046.

The FUEL CHEM technology segment generated revenues of $3,700 and $3,053 for the three-month periods ended June 30, 2026 and 2025, respectively, representing an increase of $647, or 21%, versus the same period last year. This increase in FUEL CHEM revenue for the three months ended June 30, 2026 as compared to the same period in the prior year was primarily due to increased operational dispatch at legacy accounts. FUEL CHEM technology segment revenues remained relatively flat for the six-month periods ended June 30, 2026 and 2025 at $8,176 and $8,132, respectively.

Cost of sales and gross margin

Consolidated gross margin percentage for the three-month periods ended June 30, 2026 and 2025 was 41% and 46%, respectively. For the three-month periods ended June 30, 2026 and 2025 the FUEL CHEM operating segment gross margin was 45% and 47%, respectively. FUEL CHEM gross margin decreased slightly from the prior year primarily due to demonstration costs, increased freight costs and additional internal labor costs for unit maintenance. APC segment gross margin decreased to 36% from 44% primarily due to product and project mix.

Consolidated gross margin percentage for the six-month periods ended June 30, 2026 and 2025 was 42% and 46%, respectively. For the six-month periods ended June 30, 2026 and 2025 the FUEL CHEM operating segment gross margin was 45% and 49%, respectively. Similarly to the decrease for the three-month periods ended June 30, 2026 and 2025, FUEL CHEM gross margin decreased from the prior year primarily due to increased costs. APC segment gross margin decreased to 37% from 40% primarily due to product and project mix.

Selling, general and administrative

Selling, general and administrative expenses (SG&A) were $3,594 and $3,347 for the three-month periods ended June 30, 2026 and 2025, respectively. For the three-month period ended June 30, 2026, the increase of $247 is primarily the result of an increase in professional fees of $127, an increase in employee-related expenses of $86, and an increase in travel and administrative expenses for domestic and international locations of $36. For the three-month periods ending June 30, 2026 and 2025, SG&A as a percentage of revenues decreased to 55% from 60%. The decrease versus the comparable period is primarily due to the increase in revenues.

Selling, general and administrative expenses (SG&A) were $7,310 and $6,688 for the six-month periods ended June 30, 2026 and 2025, respectively. For the six-month period ended June 30, 2026, the increase of $622 is primarily the result of an increase in employee-related expenses of $281, an increase in professional fees of $236, and an increase in travel and administrative expenses for domestic and international locations of $107. For the six-month periods ending June 30, 2026 and 2025, SG&A as a percentage of revenues increased to 58% from 56%. The increase versus the comparable period is primarily due to the increase in SG&A expenses.

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Research and development

Research and development expenses were $646 and $490 for the three-month periods ended June 30, 2026 and 2025, respectively and $1,170 and $1,060 for the six-month periods ended June 30, 2026 and 2025. The expenditures in our research and development expenses are focused on new product development efforts in the pursuit of commercial applications for technologies outside of our traditional markets, and in the development and analysis of new technologies that could represent incremental market opportunities. This includes water treatment technologies and more specifically, our DGI® Dissolved Gas Infusion Systems, an innovative alternative to current aeration technology. This infusion process has a variety of potential applications in the water and wastewater industries, including remediation, treatment, biological activity, and wastewater odor management. DGI® technology benefits include reduced energy consumption, installation costs, and operating costs, while improving treatment performance.

Interest income

Interest income was $266 for the three-month period ended June 30, 2026 compared to $537 for the same period in 2025. Interest income for the three-month period ended June 30, 2025 included $257 in interest income related to the collection of our ERC benefit. Interest income was $506 for the six-month period ended June 30, 2026 compared to $816 for the same period in 2025. Interest income primarily relates to interest received on the held-to-maturity debt securities and money market funds.

Other income, net

Other income, net was $79 for the three-month period ended June 30, 2026 compared to Other income, net of $86 for the same period in 2025. Other income, net was $79 for the six-month period ended June 30, 2026 compared to Other income, net of $20 for the same period in 2025. Other income for the three and six-month periods ended June 30, 2025 was mainly due to transactional foreign exchange gains and losses recognized from repayment of intercompany balances.

Liquidity and Sources of Capital

We have losses from operations during the six-month period ended June 30, 2026 totaling $3,161. Our cash used in operations for this same period totaled $1,741.

Our cash and cash equivalent balance as of June 30, 2026 totaled $7,620, which includes $1,004 of cash equivalents, and our working capital totaled $20,118. We have no outstanding debt other than our outstanding letters of credit, under our Investment Collateral Security agreement with BMO Harris Bank, N.A. (the Investment Collateral Security agreement), which does not have any financial covenants. We expect to continue operating under this arrangement for the foreseeable future.

Operating activities used cash of $1,741 for the six-month period ended June 30, 2026, primarily due to a decrease in accrued liabilities and other non-current liabilities of $931 and a decrease in accounts payable of $417, offset by a decrease in accounts receivable of $1,434.

Operating activities provided cash of $1,487 for the six-month period ended June 30, 2025, primarily due to a decrease in accounts receivable of $1,987, collection of the ERC receivable of $1,232, an increase in accrued liabilities and other non-current liabilities of $203, and removals of non-cash items from our net loss from continuing operations of depreciation and amortization of $345 and stock-based compensation, net of forfeitures of $212, offset by a decrease in accounts payable of $833 and an increase in inventory of $218.

Investing activities used cash of $2,502 and provided cash of $700 for the six-month periods ended June 30, 2026 and 2025, respectively. Investing activities for the six-month periods ended June 30, 2026 and 2025 primarily consisted of purchases of debt securities as investments of $9,103 and $4,949, respectively. Investing activities for the six-month periods ended June 30, 2026 and 2025 were funded by the maturities of debt securities of $7,000 and $5,750, respectively.

Financing activities used cash of $45 and $222, respectively, for the six months ended June 30, 2026 and 2025 due to taxes paid on behalf of the equity award participants on the vesting of restricted stock units.

We continue to monitor our liquidity needs and in response to our recent periods of declines in revenue and net losses have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We have evaluated our ongoing business needs and considered the cash requirements of our base business of Air Pollution Control and FUEL CHEM. This evaluation included consideration of the following: a) customer and revenue trends in our APC and FUEL CHEM business segments, b) current operating structure and expenditure levels, and c) other research and development initiatives. Based on this analysis, management believes that currently we have sufficient cash and working capital to operate our base APC and FUEL CHEM businesses. We believe our current cash position and net cash flows expected to be generated from operations are adequate to fund planned operations of the Company for the next 12 months.

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We expect additional capital expenditures during the remainder of 2026 for the DGI business, maintenance of field equipment, computer and systems, and general office equipment. We expect to fund our capital expenditures with cash from operations or cash on hand.

The Company's investment policy provides for $20,000 in funds at BMO Harris Bank, N.A. (BMO Harris) to be invested in held-to-maturity debt securities of United States (US) Treasuries, including Notes, Bonds, and Bills, or US Government Agency securities. The funds are held in money market funds until they are invested in those securities. The investments are structured to create a maturity “ladder” where the proceeds from maturities are re-invested to maintain a balance of short- and long-term investments based on expected business needs. Maturities are between three and thirty-six months. This strategy allows the Company to provide returns on excess cash, while managing liquidity and minimizing exposure to interest rate fluctuations.

The Company's Investment Collateral Security agreement is used for the sole purpose of issuing standby letters of credit and requires us to pledge our investments as collateral for 150% of the aggregate face amount of outstanding standby letters of credit. The Company pays 250 basis points on the face values of outstanding letters of credit. There are no financial covenants set forth in the Investment Collateral Security agreement. At June 30, 2026, the Company had outstanding standby letters of credit totaling approximately $1,716 under the Investment Collateral Security agreement. At June 30, 2026, the investments held as collateral totaled $2,574. Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments.

Contingencies and Contractual Obligations

Fuel Tech issues a standard product warranty with the sale of its products to customers as discussed in Note 13. There was no change in the warranty liability balance during the six months ended June 30, 2026.

Forward-Looking Statements

This Quarterly Report on Form 10-Q contains “forward-looking statements,” as defined in Section 21E of the Securities Exchange Act of 1934, as amended, which are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and reflect Fuel Tech’s current expectations regarding future growth, results of operations, cash flows, performance and business prospects, and opportunities, as well as assumptions made by, and information currently available to, our management. Fuel Tech has tried to identify forward-looking statements by using words such as “anticipate,” “believe,” “plan,” “expect,” “estimate,” “intend,” “will,” and similar expressions, but these words are not the exclusive means of identifying forward-looking statements. These statements are based on information currently available to Fuel Tech and are subject to various risks, uncertainties, and other factors, including, but not limited to, those discussed in Fuel Tech’s Annual Report on Form 10-K for the year ended December 31, 2025 in Item 1A under the caption “Risk Factors,” which could cause Fuel Tech’s actual growth, results of operations, financial condition, cash flows, performance and business prospects and opportunities to differ materially from those expressed in, or implied by, these statements. Fuel Tech undertakes no obligation to update such factors or to publicly announce the results of any of the forward-looking statements contained herein to reflect future events, developments, or changed circumstances or for any other reason. Investors are cautioned that all forward-looking statements involve risks and uncertainties, including those detailed in Fuel Tech’s filings with the Securities and Exchange Commission.

Item 3. Quantitative and Qualitative Disclosures about Market Risk

Fuel Tech’s earnings and cash flow are subject to fluctuations due to changes in foreign currency exchange rates. We do not enter into foreign currency forward contracts nor into foreign currency option contracts to manage this risk due to the immaterial nature of the transactions involved.

Item 4. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

Fuel Tech maintains disclosure controls and procedures and internal controls designed to ensure (a) that information required to be disclosed in Fuel Tech’s filings under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms, and (b) that such information is accumulated and communicated to management, including the principal executive and financial officer, as appropriate to allow timely decisions regarding required disclosure. Fuel Tech’s Chief Executive Officer and principal financial officer have evaluated the Company’s disclosure controls and procedures, as defined in Rules 13a – 15(e) and 15d -15(e) of the Exchange Act, as of the end of the period covered by this report, and they have concluded that these controls and procedures are effective.

Changes in Internal Control over Financial Reporting

There has been no change in the Company's internal control over financial reporting during the quarter covered by this report that has materially affected, or is reasonably likely to materially affect, its internal control over financial reporting.

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PART II. OTHER INFORMATION

Item 1. Legal Proceedings

We are from time to time involved in litigation incidental to our business. We are not currently involved in any litigation in which we believe an adverse outcome would have a material effect on our business, financial conditions, results of operations, or prospects.

Item 1A. Risk Factors

The risk factors included in our Annual Report on Form 10-K for fiscal year ended December 31, 2025 have not materially changed.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

None

Item 6. Exhibits

a. | Exhibits (all filed herewith)
| 31.1 | Certification of CEO pursuant to Section 302 of Sarbanes-Oxley Act of 2002
| 31.2 | Certification of principal financial officer pursuant to Section 302 of Sarbanes-Oxley Act of 2002
| 32 | Certification of CEO and principal financial officer pursuant to Section 906 of Sarbanes-Oxley Act of 2002
| 101.1 | Inline INSXBRL Instance Document - The Instance Document does not appear in the Interactive Data File because its Inline XBRL tags are embedded within the Inline XBRL document.
| 101.2 | Inline SCHXBRL Taxonomy Extension Schema Document
| 101.3 | Inline CALXBRL Taxonomy Extension Calculation Linkbase Document
| 101.4 | Inline DEFXBRL Taxonomy Extension Definition Linkbase Document
| 101.5 | Inline LABXBRL Taxonomy Extension Label Linkbase Document
| 101.6 | Inline PREXBRL Taxonomy Extension Prevention Linkbase Document
| 104 | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

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FUEL TECH, INC.

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Date: August 4, 2026 | By: | /s/ Vincent J. Arnone
|  | Vincent J. Arnone
|  | President and Chief Executive Officer
|  | (Principal Executive Officer)

Date: August 4, 2026 | By: | /s/ Ellen T. Albrecht
|  | Ellen T. Albrecht
|  | Vice President, Chief Financial Officer and Treasurer
|  | (Principal Financial Officer)

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