What changed in this filing

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Item 1. Financial Statements

2026-05-05 compared with 2025-11-04 · 71 added, 217 removed, 430 unchanged (40% of the section changed)

3 unchanged sentences

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

September 30,

Current assets:

46 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

$ 6,080 $ 6,382

1 unchanged sentence

Cost of sales

3,829 4,444 10,281 11,462

Selling, general and administrative

3,207 3,225 9,895 9,815

Research and development

450 361 1,510 1,159

7,486 8,030 21,686 22,436

Operating income (loss)

Operating loss

( 1,596 ) ( 952 )

Interest income

311 323 1,127 968

Other (expense) income, net

( 5 ) ( 63 ) 15 1,576

Income (loss) before income taxes

310 81 ( 1,114 ) ( 42 )

Income tax expense

Other expense, net

Loss before income taxes

( 1,356 ) ( 739 )

Net income (loss)

Income tax benefit

$ ( 1,355 ) $ ( 739 )

Net income (loss) per common share:

Basic net income (loss) per common share

Net loss per common share:

Basic net loss per common share

$ ( 0.04 ) $ ( 0.02 )

Diluted net income (loss) per common share

Diluted net loss per common share

$ ( 0.04 ) $ ( 0.02 )

7 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

Net income (loss)

$ ( 1,355 ) $ ( 739 )

1 unchanged sentence

Foreign currency translation adjustments

( 14 ) 106 132 ( 32 )

Comprehensive income (loss)

Comprehensive loss

$ ( 1,398 ) $ ( 604 )

3 unchanged sentences

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

The following summarizes the changes in total stockholders' equity for the three and nine months ended September 30, 2024:

The following summarizes the changes in total stockholders' equity for the three months ended March 31, 2025:

Comprehensive

6 unchanged sentences

— — 110 — — — — 110

Balance at March 31, 2024

30,385 $ 313 $ 164,957 $ ( 117,248 ) $ ( 1,891 ) $ 76 $ ( 2,251 ) $ 43,956

— — — ( 421 ) — — — ( 421 )

Foreign currency translation adjustments

— — — — 5 — — 5

Stock compensation expense

— — 124 — — — — 124

Common shares issued upon vesting of restricted stock units

2 unchanged sentences

( 24 ) — — — — — ( 24 ) ( 24 )

Balance at June 30, 2024

30,708 $ 317 $ 165,077 $ ( 117,669 ) $ ( 1,886 ) $ 76 $ ( 2,346 ) $ 43,569

— — — 80 — — — 80

Foreign currency translation adjustments

— — — — 106 — — 106

Stock compensation expense

— — 109 — — — — 109

Balance at September 30, 2024

Balance at March 31, 2025

30,769 $ 318 $ 165,405 $ ( 120,211 ) $ ( 1,780 ) $ 76 $ ( 2,370 ) $ 41,438

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

The following summarizes the changes in total stockholders' equity for the three months ended March 31, 2026:

Comprehensive

12 unchanged sentences

31,157 $ 323 $ 165,671 $ ( 123,151 ) $ ( 1,761 ) $ 76 $ ( 2,602 ) $ 38,556

— — — ( 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 $ 165,502 $ ( 120,900 ) $ ( 1,769 ) $ 76 $ ( 2,568 ) $ 40,663

— — — 303 — — — 303

Foreign currency translation adjustments

— — — — ( 14 ) — — ( 14 )

Stock compensation expense

— — 57 — — — — 57

Balance at September 30, 2025

31,075 $ 322 $ 165,559 $ ( 120,597 ) $ ( 1,783 ) $ 76 $ ( 2,568 ) $ 41,009

See notes to condensed consolidated financial statements.

2 unchanged sentences

(in thousands)

Nine Months Ended

September 30,

Three Months Ended

Operating Activities

$ ( 1,355 ) $ ( 739 )

Adjustments to reconcile net loss to net cash provided by (used in) operating activities:

Adjustments to reconcile net loss to net cash (used in) provided by operating activities:

Non-cash interest income on held-to-maturity securities

( 91 ) ( 109 )

Provision for credit losses, net of recoveries

Stock-based compensation, net of forfeitures

1 unchanged sentence

Accounts receivable

3,066 ( 845 )

Employee retention credit receivable

1,677 ( 1,677 )

Prepaid expenses, other current assets and other non-current assets

Accounts payable

( 1,095 ) ( 1,340 )

Accrued liabilities and other non-current liabilities

( 183 ) ( 249 )

Net cash provided by (used in) operating activities

Net cash (used in) provided by operating activities

( 847 ) 1,508

5 unchanged sentences

Maturities of debt securities

11,000 11,000

Net cash provided by (used in) investing activities

Net cash (used in) provided by investing activities

( 1,914 ) 1,692

5 unchanged sentences

Effect of exchange rate fluctuations on cash

Net increase (decrease) in cash and cash equivalents

Net (decrease) increase in cash and cash equivalents

( 2,830 ) 3,311

5 unchanged sentences

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

September 30, 2025

March 31, 2026

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

16 unchanged sentences

All significant intercompany transactions and balances have been eliminated.

The results of operations for the three and nine months ended September 30, 2025 are not necessarily indicative of the results to be expected for the full year ending December 31, 2025 .

The results of operations for the three months ended March 31, 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.

On March 27, 2020, the U.S.

government enacted the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") to provide certain relief as a result of the COVID- 19 pandemic.

The CARES Act provides tax relief, along with other stimulus measures, including a provision for an Employee Retention Credit (“ERC”), which allows for employers to claim a refundable tax credit against the employer share of Social Security tax for qualifying periods in 2020 and 2021.

Under the provisions of the CARES Act, the Company is eligible for a refundable employee retention credit subject to certain criteria.

As there is no authoritative guidance under U.S.

GAAP on accounting for government assistance to for-profit business entities, we account for the ERC by analogy to International Accounting Standard ("IAS") 20, Accounting for Government Grants and Disclosure of Government Assistance.

In accordance with IAS 20, management determined it had reasonable assurance for receipt of the ERC and recorded the ERC benefit of $ 1,677 as other income on the Statement of Operations for the nine months ended September 30, 2024 .

We received full payment of this benefit during the nine months ended September 30, 2025 .

Summary of Significant Accounting Policies

3 unchanged sentences

A portion of the funds invested are restricted as collateral under the Investment Collateral Security agreement (see Note 10 ).

At September 30, 2025 , the amount of funds collateralized under the Investment Collateral Security agreement is $ 4,711 relating to existing standby letters of credit that is comprised of $ 2,879 with varying maturity dates that expire no later than September 30, 2026 and $ 1,832 with a latest maturity date of October 8, 2028.

At March 31, 2026 , the amount of funds collateralized under the Investment Collateral Security agreement is $ 2,798 relating to existing standby letters of credit that is comprised of $ 2,746 with varying maturity dates that expire no later than March 31, 2027 and $ 52 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.

12 unchanged sentences

Held-to-maturity debt securities:

September 30, 2025

March 31, 2026

December 31, 2025

4 unchanged sentences

$ 21,478 $ 20,009

The following table provides the amortized cost and fair value of debt securities by maturities at September 30, 2025 :

The following table provides the amortized cost and fair value of debt securities by maturities at March 31, 2026 :

Amortized Cost

2 unchanged sentences

After one year through two years

After two years through three years

$ 21,465 $ 21,478

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 September 30, 2025 and December 31, 2024 , inventory included equipment constructed for resale of $ 176 and spare parts, net of reserves, of $ 226 and $ 221 , respectively.

At March 31, 2026 and December 31, 2025 , inventory included equipment constructed for resale of $ 176 and spare parts, net of reserves, of $ 188 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 $ 32 and $ 44 as of September 30, 2025 and December 31, 2024 , respectively.

In process equipment for inventory recorded as Other assets was $ 52 and $ 53 as of March 31, 2026 and December 31, 2025 , respectively.

In ventories are periodically evaluated to identify obsolete or otherwise impaired parts and are written off when management determines usage is not probable.

14 unchanged sentences

(Write-offs) / Recoveries

At September 30, 2025

At March 31, 2026

Disaggregated Revenue by Product Technology

1 unchanged sentence

Three Months Ended

Nine Months Ended

September 30,

Air Pollution Control

Technology solutions

$ 1,227 $ 2,554 $ 3,443 $ 6,837

840 424 1,516 1,428

Ancillary revenue

640 246 1,556 1,226

Total Air Pollution Control technology revenues

2,707 3,224 6,515 9,491

FUEL CHEM technology solutions

4,783 4,627 12,915 10,359

Total Revenues

3 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

United States

2 unchanged sentences

Latin America

166 208 579 816

698 785 1,882 1,627

68 741 262 2,443

932 664 1,280 1,445

Total Foreign Revenues

1,864 2,398 4,003 6,331

Total Revenues

3 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

Products transferred at a point in time

1 unchanged sentence

Products and services transferred over time

1,227 2,554 3,443 6,837

Total Revenues

5 unchanged sentences

These assets are reported on the Condensed Consolidated Balance Sheets on a contract-by-contract basis at the end of each reporting period.

At September 30, 2025 , December 31, 2024 , and December 31, 2023 , contract assets for APC technology projects were approximately $ 1,300 , $ 2,075 , and $ 2,285 , respectively.

At March 31, 2026 , December 31, 2025 , and December 31, 2024 , contract assets for APC technology projects were approximately $ 974 , $ 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 $ 2,200 , $ 721 , and $ 1,279 at September 30, 2025 , December 31, 2024 , and December 31, 2023 , respectively, and are included in other accrued liabilities on the Condensed Consolidated Balance Sheets.

Changes in the contract asset and liability balances during the nine -month period ended September 30, 2025 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 $ 1 and $ 544 for the three and nine months ended September 30, 2025 , respectively, and $ 20 and $ 1,241 for the three and nine months ended September 30, 2024 , respectively, which represented revenue from progress towards completion of our APC technology contracts.

As of September 30, 2025 and December 31, 2024 , we had no construction contracts in progress that were identified as a loss contract.

Contract liabilities were $ 1,066 , $ 1,026 , and $ 721 at March 31, 2026 , December 31, 2025 , and December 31, 2024 , respectively, and are included in other accrued liabilities on the Condensed Consolidated Balance Sheets.

Changes in the contract asset and liability balances during the three -month period ended March 31, 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 $ 452 and $ 372 for the three months ended March 31, 2026 and 2025 , respectively.

As of March 31, 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 September 30, 2025 , the aggregate amount of the transaction price allocated to remaining performance obligations was $ 9,472 .

As of March 31, 2026 , the aggregate amount of the transaction price allocated to remaining performance obligations was $ 6,923 .

The Company expects to recognize revenue on approximately $ 6,000 of the remaining performance obligations over the next 12 months with the remaining recognized thereafter.

1 unchanged sentence

The components of accounts receivable are as follows:

September 30, 2025

March 31, 2026

December 31, 2025

2 unchanged sentences

Unbilled receivables

Receivable for employee retention credit

Other short-term receivables

6 unchanged sentences

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 September 30, 2025 includes staff rationalization and reduction, supplier and partner engagement, and the monetization of certain assets.

The transition associated with the suspension of the APC business which has taken place through March 31, 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 nine months ended September 30, 2025 and 2024 in China as follows:

The following table presents our revenues and net loss for the three months ended March 31, 2026 and 2025 in China as follows:

Three Months Ended

Nine Months Ended

September 30,

Total revenues

( 13 ) ( 18 )

( 12 ) ( 13 ) ( 42 ) ( 41 )

The following table presents net assets in China as of September 30, 2025 and December 31, 2024 :

September 30, 2025

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

March 31, 2026

December 31, 2025

6 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

Foreign currency translation

3 unchanged sentences

Foreign currency translation adjustments (1)

( 14 ) 106 132 ( 32 )

Total accumulated other comprehensive loss

2 unchanged sentences

Treasury Stock

Common stock held in treasury totaled 1,206,741 and 1,059,056 with a cost of $ 2,568 and $ 2,346 at September 30, 2025 and December 31, 2024 , respectively.

Common stock held in treasury totaled 1,233,052 and 1,206,741 with a cost of $ 2,602 and $ 2,568 at March 31, 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.

3 unchanged sentences

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 months ended September 30, 2025 and 2024, basic earnings per share has been adjusted to include dilutive options and RSUs.

For the nine months ended September 30, 2025 and 2024, 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 nine months ended September 30, 2025 and 2024 :

For the three months ended March 31, 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 months ended March 31, 2026 and 2025 :

Three Months Ended

Nine Months Ended

September 30,

Basic weighted-average shares

1 unchanged sentence

Unexercised options and unvested RSUs

219,000 140,000 — —

Diluted weighted-average shares

31,091,335 30,718,000

For the three and nine months ended September 30, 2025 , Fuel Tech had warrants of 2,850,000 which were antidilutive for the purpose of the calculation of diluted earnings per share.

For the nine months ended September 30, 2025 , Fuel Tech also had weighted-average outstanding equity awards of 73,800 which were antidilutive or represent out-of-the-money options for the purpose of the calculation of diluted earnings per share.

For the nine months ended September 30, 2025 , Fuel Tech had incremental equity awards of 297,300 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 nine months ended September 30, 2024 , Fuel Tech had weighted-average outstanding equity awards of 132,000 and 283,700 , 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 nine months ended September 30, 2024 , Fuel Tech had incremental equity awards of 279,000 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.

For the three months ended March 31, 2026 and 2025 , Fuel Tech had weighted-average outstanding equity awards of 27,000 and 135,900 , 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 months ended March 31, 2026 and 2025 , Fuel Tech had incremental equity awards of 159,300 and 322,700 , 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.

6 unchanged sentences

There are a maximum of 3,249,134 shares that may be issued or reserved for awards to participants under the Incentive Plans.

As of September 30, 2025 , Fuel Tech had 2,668,885 shares available for issuance under the Incentive Plans.

We did not record any excess tax benefits within income tax expense for the three and nine months ended September 30, 2025 and 2024 .

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 nine months ended September 30, 2025 and 2024 .

As of March 31, 2026 , Fuel Tech had 3,120,297 shares available for issuance under the Incentive Plans.

We did not record any excess tax benefits within income tax expense for the three months ended March 31, 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 months ended March 31, 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 nine months ended September 30, 2025 and 2024 were as follows:

The components of stock-based compensation for the three months ended March 31, 2026 and 2025 were as follows:

Three Months Ended

Nine Months Ended

September 30,

Stock options and restricted stock units, net of forfeitures

$ 57 $ 109 $ 269 $ 337

After-tax effect of stock-based compensation

$ 57 $ 109 $ 269 $ 337

Stock Options

9 unchanged sentences

and ( 3 ) expected life of the option – an estimate based on historical experience including the effect of employee terminations.

Stock option activity for Fuel Tech’s Incentive Plans for the nine months ended September 30, 2025 was as follows:

Stock option activity for Fuel Tech’s Incentive Plans for the three months ended March 31, 2026 was as follows:

Weighted- Average

3 unchanged sentences

Expired or forfeited

( 105,000 ) 2.44

Outstanding on September 30, 2025

Outstanding on March 31, 2026

71,000 $ 1.20 1.10 $ 11

Exercisable on September 30, 2025

Exercisable on March 31, 2026

71,000 $ 1.20 1.10 $ 11

As of September 30, 2025 , there was no unrecognized compensation cost related to non-vested stock options granted under the Incentive Plans.

As of March 31, 2026 , there was no unrecognized compensation cost related to non-vested stock options granted under the Incentive Plans.

Restricted Stock Units

2 unchanged sentences

Compensation cost, adjusted for estimated forfeitures, is amortized on a straight-line basis over the requisite service perio d.

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 2025 and 2026.

The target amount of RSUs for each of four possible RSU award components is set for each Participating Executive for 2025 and 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.

4 unchanged sentences

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 September 30, 2025 , there is $ 1,064 of unrecognized compensation cost related to all non-vested share-based compensation arrangements granted under the Incentive Plan.

At March 31, 2026 , there is $ 608 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 1.62 yea rs.

A summary of restricted stock unit activity for the nine months ended September 30, 2025 is as follows:

A summary of restricted stock unit activity for the three months ended March 31, 2026 is as follows:

Weighted Average

3 unchanged sentences

( 425,100 ) 1.02

Unvested restricted stock units at September 30, 2025

Unvested restricted stock units at March 31, 2026

646,023 $ 1.10

The fair value of restricted stock that vested during the nine -month period ended September 30, 2025 was $ 654 .

The fair value of restricted stock that vested during the three -month period ended March 31, 2026 was $ 125 .

Deferred Directors Fees

2 unchanged sentences

In accordance with Accounting Standards Codification (ASC) 718, Fuel Tech accounts for these awards as equity awards as opposed to liability awards.

During the nine -month periods ended September 30, 2025 and 2024 , Fuel Tech recorded no stock-based compensation expense under the Deferred Plan.

The following table summarizes information about warrants outstanding and exercisable at September 30, 2025 :

During the three -month periods ended March 31, 2026 and 2025 , Fuel Tech recorded no stock-based compensation expense under the Deferred Plan.

The following table summarizes information about warrants outstanding and exercisable at March 31, 2026 :

Exercise Price Number Outstanding/Exercisable Weighted Average Remaining Life in Years Weighted Average Exercise Price

5 unchanged sentences

There are no financial covenants set forth in the Investment Collateral Security agreement.

At September 30, 2025 , the Company had outstanding standby letters of credit totaling approximately $ 3,141 under the Investment Collateral Security agreement.

At September 30, 2025 , the investments held as collateral totaled $ 4,711 .

At March 31, 2026 , the Company had outstanding standby letters of credit totaling approximately $ 1,866 under the Investment Collateral Security agreement.

At March 31, 2026 , the investments held as collateral totaled $ 2,798 .

Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments.

19 unchanged sentences

Air Pollution

Three months ended September 30, 2025

Control Segment

Revenues from external customers

$ 2,707 $ 4,783 $ — $ 7,490

Cost of sales

( 1,428 ) ( 2,401 ) — ( 3,829 )

1,279 2,382 — 3,661

Selling, general and administrative

— — ( 3,207 ) ( 3,207 )

Research and development

— — ( 450 ) ( 450 )

Operating income (loss) from operations

$ 1,279 $ 2,382 $ ( 3,657 ) $ 4

Air Pollution

Three months ended September 30, 2024

Control Segment

Revenues from external customers

$ 3,224 $ 4,627 $ — $ 7,851

Cost of sales

( 2,095 ) ( 2,349 ) — ( 4,444 )

1,129 2,278 — 3,407

Selling, general and administrative

— — ( 3,225 ) ( 3,225 )

Research and development

— — ( 361 ) ( 361 )

Operating income (loss) from operations

$ 1,129 $ 2,278 $ ( 3,586 ) $ ( 179 )

Air Pollution

Nine months ended September 30, 2025

Three months ended March 31, 2026

Control Segment

8 unchanged sentences

— — ( 524 ) ( 524 )

Operating income (loss) from operations

Income (loss) from operations

$ 615 $ 2,029 $ ( 4,240 ) $ ( 1,596 )

Air Pollution

Nine months ended September 30, 2024

Three months ended March 31, 2025

Control Segment

8 unchanged sentences

— — ( 570 ) ( 570 )

Operating income (loss) from operations

Income (loss) from operations

$ 425 $ 2,534 $ ( 3,911 ) $ ( 952 )

4 unchanged sentences

Three Months Ended

Nine Months Ended

September 30,

United States

1 unchanged sentence

$ 6,080 $ 6,382

$ 7,490 $ 7,851 $ 19,430 $ 19,850

September 30,

United States

3 unchanged sentences

The components of other accrued liabilities are as follows:

September 30, 2025

March 31, 2026

December 31, 2025

1 unchanged sentence

$ 1,066 $ 1,026

Deferred revenue

Warranty reserve (Note 13)

Deferred revenue

Accrued professional fees

13 unchanged sentences

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 nine months ended September 30, 2025 and 2024 .

The warranty liability balance was $ 159 at September 30, 2025 and December 31, 2024 .

The Company’s effective tax rate is approximately 1.0 % and 42.9 % for the nine -month periods ended September 30, 2025 and 2024 , respectively.

The Company's effective tax rate differs from the statutory federal tax rate of 21 % for the nine -month periods ended September 30, 2025 and 2024 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.

There was no change in the warranty liability balance included in the other accrued liabilities line of the Condensed Consolidated Balance Sheets during the three months ended March 31, 2026 and 2025 .

The warranty liability balance was $ 159 at March 31, 2026 and December 31, 2025 .

The Company’s effective tax rate is approximately ( 0.1 % ) and 0.0 % for the three -month periods ended March 31, 2026 and 2025 , respectively.

The Company's effective tax rate differs from the statutory federal tax rate of 21 % for the three -month periods ended March 31, 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 nine -month periods ended September 30, 2025 and 2024 .

On July 4, 2025, the One Big Beautiful Bill Act was signed into law.

This act includes changes to the U.S.

corporate income tax system.

The Company is currently evaluating the full effect of the legislation, but does not expect it to have a material impact on our Consolidated Financial Statements.

Subsequent Events

On October 3, 2025 the Company purchased certain intellectual property assets of Wahlco, Inc., a leading environmental equipment and services company, for a purchase price of $ 350 .

The intellectual property assets consist of technology rights, patents, and trademarks relating to Wahlco, Inc.

and foreign tax rates, foreign losses incurred with no related tax benefit, non-deductible commissions, and non-deductible meals and entertainment expenses for the three -month periods ended March 31, 2026 and 2025 .

FUEL TECH, INC.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-Q

Item 1. Financial Statements