What changed in this filing

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Item 9A. Controls and Procedures

2026-03-10 compared with 2025-03-05 · 65 added, 48 removed, 226 unchanged (33% of the section changed)

15 unchanged sentences

Based on this evaluation, our management concluded that our internal control over financial reporting was effective as of December 31, 2025.

We acquired Legacy Arq during the first quarter of 2023 (refer to Item 8.

Note 12 of this Report).

As permitted by Securities and Exchange Commission Staff interpretive guidance for newly acquired businesses, management excluded Legacy Arq from its evaluation of internal control over financial reporting as of December 31, 2023.

We incorporated Legacy Arq into our annual report on internal control over financial reporting for our year ending December 31, 2024.

As of December 31, 2023, Legacy Arq net assets totaled $40.5 million.

Legacy Arq contributed $11.7 million of net loss in our Consolidated Statements of Operations for the year ended December 31, 2023 .

Our independent registered public accounting firm, Moss Adams LLP, has issued an attestation report on our internal control over financial reporting as of December 31, 2024.

Our independent registered public accounting firm, Baker Tilly US, LLP, has issued an attestation report on our internal control over financial reporting as of December 31, 2025.

Changes in Internal Control Over Financial Reporting

We acquired Legacy Arq during the first quarter of our fiscal year ended December 31, 2023.

As such, Legacy Arq's control environment and processes are included in the scope of our assessment of our internal controls over financial reporting beginning in the first quarter of our fiscal year ended December 31, 2024.

Other than as discussed above, during the three months ended December 31, 2024 there were no changes to our internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) that have materially affected or are reasonably likely to materially affect our internal control over financial reporting.

During the three months ended December 31, 2025 there were no changes to our internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) that have materially affected or are reasonably likely to materially affect our internal control over financial reporting.

Report of Independent Registered Public Accounting Firm

The Shareholders and the Board of Directors

To the Shareholders and the Board of Directors

Opinion on Internal Control over Financial Reporting

3 unchanged sentences

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the consolidated balance sheets of Arq, Inc.

(and subsidiaries) as of December 31, 2024 and 2023, with the related consolidated statements of operations, changes in stockholders’ equity and cash flows for each of the years then ended, and the related notes (collectively referred to as the “consolidated financial statements”) and our report dated March 5, 2025, expressed an unqualified opinion on those consolidated financial statements.

(and subsidiaries) as of December 31, 2025 and 2024, the related consolidated statements of operations, changes in stockholders’ equity and cash flows for the years then ended, and the related notes (collectively referred to as the “consolidated financial statements”) and our report dated March 9, 2026, expressed an unqualified opinion on those consolidated financial statements.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management Report on Internal Control over Financial Reporting included in Item 9A.

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Report on Internal Control over Financial Reporting included in Item 9A.

Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit.

13 unchanged sentences

Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

/s/ Moss Adams LLP

/s/ Baker Tilly US, LLP

Denver, Colorado

March 9, 2026

We have served as the Company’s auditor since 2017.

Other Information

Rule 10b5-1 and non-Rule 10b5-1 Trading Arrangements

During the three months ended December 31, 2025, no director or officer of the Company adopted or terminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement, as each term is defined in Item 408(a) of Regulation S-K.

Second Loan Modification Agreement

On March 5, 2026, certain subsidiaries of the Company, including Corbin Project LLC, Arq Projects Holding Company LLC, Arq Corbin LLC and Arq Corbin Land LLC, each a Delaware limited liability company (collectively, “Borrowers”) and Community Trust Bank, Inc., a Kentucky corporation (“CTB”) entered into the second loan modification agreement (the "Second Loan Modification Agreement") to the Loan Agreement (USDA Guaranteed Loan) by and among CTB and the Borrowers dated January 27, 2021, as amended by that certain letter agreement dated January 21, 2022, that certain Loan Modification Agreement dated June 2, 2023 and as otherwise amended, modified and/or extended by the parties from time to time (collectively, the "Loan Agreement").

Pursuant to the terms of the Second Loan Modification Agreement, CTB agreed to (a) waive the Borrowers' obligation to satisfy certain financial covenants for the fiscal year ended December 31, 2025, and (b) suspend financial covenant testing for the fiscal year ending December 31, 2026.

As a condition to CTB's entry into the Second Loan Modification Agreement, the Borrowers agreed to deposit an additional $752,500 into the Interest Reserve Account, as defined in and established by the Loan Agreement.

The Borrowers may withdraw from the Interest Reserve Account down to the Required Minimum Balance, as defined in the Second Loan Modification Agreement.

The foregoing description of the Second Loan Modification Agreement is only a summary of its material terms and does not purport to be complete and is qualified in its entirety by reference to the full text of the Second Loan Modification Agreement, which is filed as Exhibit 10.24 to this Annual Report on Form 10-K and incorporated herein by reference.

Departure of Chief Operating Officer and Chief Financial Officer

On March 4, 2026, the Company eliminated the role of Chief Operating Officer.

Jeremy “Deke” Williamson will cease serving in that role, effective immediately.

Williamson will remain employed by the Company until April 18, 2026, after which his employment will terminate.

Additionally, Jay Voncannon, Chief Financial Officer and principal financial officer of the Company, will cease serving in these roles, effective immediately.

Voncannon will remain employed by the Company until April 18, 2026, after which date his employment will terminate.

The Company expects to enter into a separation agreement and release of claims with each of Messrs.

Voncannon and Williamson, the terms of which will be disclosed once available.

Appointment of Principal Financial Officer

On March 4, 2026, the Board designated Stacia Hansen, the Company’s Chief Accounting Officer, Treasurer and principal accounting officer, as the Company’s principal financial officer, effective immediately.

The remaining information called for by Item 5.02(c) of Form 8-K has been previously reported and can be found in the Company’s definitive proxy statement and Current Report on Form 8-K, each filed with the Securities and Exchange Commission on April 21, 2025 and November 8, 2023, respectively, which information is incorporated by reference herein.

Disclosure Regarding Foreign Jurisdictions that Prevent Inspections

15 unchanged sentences

Total 1,811,293 1,037,061

(1) Includes securities registered for issuance under the 2017 Omnibus Incentive Plan, 2022 Omnibus Incentive Plan and 2024 Omnibus Incentive Plan.

(1) Includes securities registered for issuance under the 2022 Omnibus Incentive Plan and 2024 Omnibus Incentive Plan.

(2) Represent shares subject to unvested performance share units.

41 unchanged sentences

8-K 001-37822 4.7 April 14, 2023

4.9 Se venth Amendment to Tax Asse t Protection Plan dated as of April 15, 2024, by and between the Company and Computershare Trust Company, N.

4.9 Seventh Amendment to Tax Asset Protection Plan dated as of April 15, 2024, by and between the Company and Computershare Trust Company, N.A.

as rights agent

8-K 001-37822 4.1 April 16, 2024

4.10 Eighth Amendment to Tax Asset Protection Plan dated as of April 8, 2025, by and between the Company and Computershare Trust Company, N.A.

as rights agent

8-K 001-37822 4.1 April 11, 2025

4.11 Description of the Registrant's Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934

3 unchanged sentences

2022 Omnibus Incentive Plan **

8-K 001-37822 10.1 June 22, 2017

10.2 Advanced Emissions Solutions, Inc.

2022 Omnibus Incentive Plan **

8-K 001-37822 10.1 May 17, 2022

2 unchanged sentences

Exhibit Filing Date

10.3 Form of Restricted Stock Award Agreement under the 2022 Omnibus Incentive Pla n **

10.2 Form of Restricted Stock Award Agreement under the 2022 Omnibus Incentive Plan **

10.3 March 12, 2024

2 unchanged sentences

10.4 Arq, Inc.

202 4 Omnibus Incentive P lan

2024 Omnibus Incentive Plan

001-37822 10.1 June 13, 2024

11 unchanged sentences

10-Q 000-50216 10.87 August 12, 2011

10.10 Amended and Restated Limited Liability Company Operating Agreement by and between ADA-ES, Inc., NexGen Refined Coal, LLC and Clean Coal Solutions Services, LLC dated November 20, 2013

10.9 Amended and Restated Limited Liability Company Operating Agreement of Clea n Coal Solutions Service s , LLC, by and between ADA-ES, Inc.

and NexGen Refined Coal, LLC dated November 20, 2013

10-K 000-54992 10.38 February 29, 2016

33 unchanged sentences

8-K 001-37822 10.1 February 13, 2024

10.23 Securities Purchase Agreement, dated as of February 1, 2023, by and among Advanced Emissions Solutions, Inc.

and Arq Limited ***

8-K 001-37822 2.1 February 1, 2023

10.22 Loan Agreement among Community Trust Bank, Inc.;

6 unchanged sentences

8-K 001-37822 10.1 June 6, 2023

10.26 Securities Purchase Agreement dated as of May 15, 2024, by and among the Company and the Purchasers named therein.

8-K 001-37822 10.1 May 16, 2024

10.27 Registration Rights Agreement dated as of May 15, 2024, by and among the Company and the Purchasers named therein.

8-K 001-37822 10.2 May 16, 2024

10.28 Underwriting Agreement, dated September 20, 2024, by and between the Company and Canaccord Genuity LLC as representative of the underwriters named therein.

8-K 001-37822 1.1 September 20, 2024

10.24 Second Loan Modification Agreement, dated as of March 5, 2026, by and among Community Trust Bank, Inc., Corbin Project LLC, Arq Projects Holding Company LLC, Arq Corbin LLC and Arq Corbin Land LLC.* †

10.25 Credit, Security and Guaranty Agreement, dated as of December 27, 2024, by and among Arq, Inc., certain subsidiaries of Arq, Inc., MidCap Funding IV Trust as agent, and the lenders from time to time party thereto.†

8-K 001-37822 10.1 January 2, 2025

10.26 Amendment No.

1, dated May 6, 2025, to Credit, Security and Guaranty Agreement, dated as of December 27, 2024, by and among Arq, Inc., certain subsidiaries of Arq, Inc., MidCap Funding IV Trust as agent, and the lenders from time to time party thereto.***

10-Q 001-37822 10.2 May 7, 2025

10.27 Amendment No.

2, dated December 9, 2025, to Credit, Security and Guaranty Agreement, dated as of December 27, 2024, by and among Arq, Inc., certain subsidiaries of Arq, Inc., MidCap Funding IV Trust as agent, and the lenders from time to time party thereto.***

8-K 001-37822 10.1 December 11, 2025

10.28 Amendment No.

3, dated January 28, 2026, to Credit, Security and Guaranty Agreement, dated as of December 27, 2024, by and among Arq, Inc., certain subsidiaries of Arq, Inc., MidCap Funding IV Trust as agent, and the lenders from time to time party thereto.

8-K 001-37822 10.1 January 29, 2026

10.29 Amendment No.

4, dated February 27, 2026, to Credit, Security and Guaranty Agreement, dated as of December 27, 2024, by and among Arq, Inc., certain subsidiaries of Arq, Inc., MidCap Funding IV Trust as agent, and the lenders from time to time party thereto.

8-K 001-37822 10.1 March 3, 2026

10.30 Employment Agreement by and between Robert E.

6 unchanged sentences

8-K 001-37822 10.1 November 8, 2023

E mployment Agreement by and between Clay S mith and Advanced E missions Solutions, I nc.

, dated April 26, 2024 .

19 A rq Insider Trading Policy *

10.33 Employment Agreement by and between Clay Smith and Advanced Emissions Solutions, Inc., dated April 26, 2024.**,***

10-K 001-37822 10.33 March 5, 2025

10.34 Employment Agreement by and between Jay Voncannon and Arq, Inc., dated effective April 2, 2025.**, ***

8-K 001-37822 10.1 April 2, 2025

16.1 Letter of Moss Adams LLP to the Securities and Exchange Commission, dated June 9, 2025.

8-K 001-37822 16.1 June 9, 2025

19 Arq , Inc.

Insider Trading Policy

10-K 001-37822 19 March 5, 2025

21.1 Subsidiaries of Arq, Inc.

23.1 Consent of Moss Adams LLP *

10-K 001-37822 21.1 March 5, 2025

23.1 Consent of Baker Tilly US, LLP *

31.1 Certification of Principal Executive Officer of Arq, Inc.

Pursuant to 17 CFR 240.13a-14(a) or 17 CFR 240.15d-14(a) *

Description Form File No.

Incorporated by Reference

Exhibit Filing Date

31.2 Certification of Principal Financial Officer of Arq, Inc.

3 unchanged sentences

95 Mine Safety Disclosure Exhibit *

97 Clawback Policy

97 C lawback Policy

001-37822 97 March 12, 2024

Description Form File No.

Incorporated by Reference

Exhibit Filing Date

101 The following financial statements, formatted in Inline XBRL:

27 unchanged sentences

March 10, 2026

By /s/ Carol Eicher By /s/ Gilbert Li

Carol Eicher, Director Gilbert Li, Director

March 5, 2025 Date:

March 5, 2025

By /s/ Julian McIntyre By /s/ Laurie Bergman

Julian McIntyre, Director Laurie Bergman, Director

By /s/ Carol Eicher By /s/ Julian McIntyre

Carol Eicher, Director Julian McIntyre, Director

March 10, 2026 Date:

March 10, 2026

Spencer Wells By /s/ Robert Rasmus

Spencer Wells, Director Robert Rasmus, Director

By /s/ Laurie Bergman By /s/ Robert Rasmus

Laurie Bergman, Director Robert Rasmus, Director

March 10, 2026 Date:

1 unchanged sentence

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-K

Item 9A. Controls and Procedures