AAON, INC. 10-K

Item 9A. Controls and Procedures. (a) Evaluation of Disclosure Controls and Procedures Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, has evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) as of December 31, 2025. Based upon the evaluation, our principal executive and principal financial officers have concluded that our disclosure controls and procedures were effective at December 31, 2025, to ensure the information required to be disclosed by us in reports that we file or submit under the Exchange Act is accumulated and communicated to our management, including our principal executive and principal financial officers, as appropriate, to allow timely decisions regarding required disclosure and is recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. (b) Management’s Annual Report on Internal Control over Financial Reporting Our management is responsible for establishing and maintaining adequate internal control over our financial reporting as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act. Our internal control over financial reporting is a process designed by, or under the supervision of, our principal executive and principal financial officers, and effected by our board of directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. 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. In making our assessment of internal control over financial reporting, management has used the criteria issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) in the 2013 Internal Control—Integrated Framework . Based on our assessment, our management concluded that the Company maintained effective internal control over financial reporting as of December 31, 2025. The effectiveness of the Company’s internal control over financial reporting as of December 31, 2025, has been audited by Grant Thornton LLP, our independent registered public accounting firm, as stated in their report which is included in this Item 9A of this report on Form 10-K. (c) Changes in Internal Control over Financial Reporting There have been no changes in internal control over financial reporting that occurred during our last fiscal quarter that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. 82 REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM Board of Directors and Stockholders AAON, Inc. Opinion on internal control over financial reporting We have audited the internal control over financial reporting of AAON, Inc. (a Nevada corporation) and subsidiaries (the “Company”) as of December 31, 2025, based on criteria established in the 2013 Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on criteria established in the 2013 Internal Control—Integrated Framework issued by COSO. We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the consolidated financial statements of the Company as of and for the year ended December 31, 2025, and our report dated March 2, 2026 expressed an unqualified opinion on those 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’s Annual Report on Internal Control over Financial Reporting (“Management’s Report”). Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion. Definition and limitations of internal control over financial reporting A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. 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/ GRANT THORNTON LLP Tulsa, Oklahoma March 2, 2026 Item 9B. Other Information. Rule 10b5-1 Trading Arrangements 83 The following table describes contracts, instructions or written plans for the purchase or sale of our securities intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). Name and Title of Director or Officer Date of Adoption of Arrangement Duration of the Arrangement Aggregate Number of Securities to be Purchased or Sold Pursuant to the Arrangement Rebecca A. Thompson December 13, 2024 Terminated December 31, 2025 91,500 Chief Financial Officer & Treasurer December 16, 2025 March 16, 2027 41,565 PART III Item 10. Directors, Executive Officers and Corporate Governance. The information required by Items 401, 405, 406 and 407(c)(3), (d)(4) and (d)(5) of Regulation S-K is incorporated by reference to the information contained in our definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with our annual meeting of stockholders scheduled to be held on May 12, 2026. Code of Ethics We adopted a code of ethics that applies to our principal executive officer, principal financial officer, and principal accounting officer or persons performing similar functions, as well as other employees and directors. Our code of ethics can be found on our website at www.aaon.com. We will also provide any person without charge, upon request, a copy of such code of ethics. Requests may be directed to AAON, Inc., 2425 South Yukon Avenue, Tulsa, Oklahoma 74107, attention Rebecca A. Thompson, or by calling (918) 382-6216. Item 11. Executive Compensation. The information required by Items 402 and 407(e)(4) and (e)(5) of Regulation S-K is incorporated by reference to the information contained in our definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with our annual meeting of stockholders scheduled to be held on May 12, 2026. Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters. The information required by Item 403 and Item 201(d) of Regulation S-K is incorporated by reference to the information contained in our definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with our annual meeting of stockholders scheduled to be held May 12, 2026. Item 13. Certain Relationships and Related Transactions, and Director Independence. The information required to be reported pursuant to Item 404 of Regulation S-K and paragraph (a) of Item 407 of Regulation S-K is incorporated by reference in our definitive proxy statement relating to our annual meeting of stockholders scheduled to be held May 12, 2026. Our Code of Conduct guides the Board of Directors in its actions and deliberations with respect to related party transactions. Under the Code, conflicts of interest, including any involving the directors or any Named Officers, are prohibited except under any guidelines approved by the Board of Directors. Only the Board of Directors may waive a provision of the Code of Conduct for a director or a Named Officer, and only then in compliance with all applicable laws, rules and regulations. We have not entered into any new material related party transactions and have no preexisting material related party transactions in 2025, 2024, or 2023. 84 Item 14. Principal Accountant Fees and Services. This information is incorporated by reference in our definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with our annual meeting of stockholders scheduled to be held May 12, 2026. 85 PART IV Item 15. Exhibits and Financial Statement Schedules. (a) Financial statements. (1) The consolidated financial statements and the report of independent registered public accounting firm are included in Item 8 of this Form 10-K. (2) The consolidated financial statements other than those listed at item (a)(1) above have been omitted because they are not required under the related instructions or are not applicable. (3) The exhibits listed at item (b) below are filed as part of, or incorporated by reference into, this Form 10-K. (b) Exhibits: (3) (A) Amended and Restated Articles of Incorporation (i) (B) Amended and Restated Bylaws (ii) (4.1) Amended and Restated Loan Agreement (dated November 24, 2021) and related documents (iii) (4.2) First Amendment to the Amended and Restated Loan Agreement (dated May 27, 2022) and related documents (iv) (4.3) Third Amendment to the Amended and Restated Loan Agreement (dated December 16, 2024) and related documents (v) (4. 4 ) Fourth Amendment to the Amended and Restated Loan Agreement (dated April 4, 2025) and related documents (4. 5 ) Fifth Amendment to the Amended and Restated Loan Agreement (dated May 29, 2025) and related documents (xii) (4. 6 ) Sixth Amendment to the Amended and Restated Loan Agreement (dated December 29, 2025) and related documents (xiii) (4.16) Description of Securities (10.1) AAON, Inc. 2007 Long-Term Incentive Plan, as amended (vi) (10.2) AAON, Inc. 2016 Long-Term Incentive Plan (vii) (10.3) AAON, Inc. 2024 Long-Term Incentive Plan (viii) ( 10.4 ) Executive Severance Plan (adopted July 30, 2024) (ix) (19) AAON Insider Trading Policy (adopted December 11, 2024) (21) List of Subsidiaries (23) Consent of Grant Thornton LLP (31.1) Certification of CEO (31.2) Certification of CFO (32.1) Section 1350 Certification – CEO (32.2) Section 1350 Certification – CFO (97.1) Executive Officer Compensation Recovery Policy (x) (99.1) Membership Interest Purchase Agreement - Acquisition of BASX, LLC (dated November 18, 2021) (xi) (101) (INS) Inline XBRL Instance Document (101) (SCH) Inline XBRL Taxonomy Extension Schema (101) (CAL) Inline XBRL Taxonomy Extension Calculation Linkbase (101) (DEF) Inline XBRL Taxonomy Extension Definition Linkbase 86 (101) (LAB) Inline XBRL Taxonomy Extension Label Linkbase (101) (PRE) Inline XBRL Taxonomy Extension Presentation Linkbase (104) Cover Page Interactive Data File (embedded within the Inline XBRL Document and included in Exhibit 101) (i) Incorporated herein by reference to the exhibit to our Form 10-Q dated June 30, 2024. (ii) Incorporated herein by reference to the exhibit to our Form 8-K dated March 9, 2023. (iii) Incorporated herein by reference to exhibit to our Form 8-K dated November 24, 2021. (iv) Incorporated herein by reference to the exhibits to our Form 8-K dated May 27, 2022. (v) Incorporated herein by reference to the exhibits to our Form 8-K dated December 16, 2024. (vi) Incorporated herein by reference to our Form S-8 Registration Statement No. 333-151915 dated June 24, 2008 and our Form S-8 Registration Statement No. 333-207737 dated November 2, 2015. (vii) Incorporated herein by reference to our Form S-8 Registration Statement No. 333-212863 dated August 2, 2016, our Form S-8 Registration Statement No. 333-226512 dated August 2, 2018, and our Form S-8 Registration Statement No. 333-241538 dated August 6, 2020. (viii) Incorporated herein by reference to our Form S-8 Registration Statement No. 333-279594 dated May 21, 2024 and our Form S-8 POS Registration Statement No. 333-241538 dated June 25, 2024. (ix) Incorporated herein by reference to the exhibit to our Form 8-K dated July 30, 2024. (x) Incorporated herein by reference to exhibits to our Annual Report on Form 10-K for the fiscal year ended December 31, 2023. (xi) Incorporated herein by reference to exhibits to our Annual Report on Form 10-K for the fiscal year ended December 31, 2021. (xii) Incorporated herein by reference to the exhibits to our Form 8-K dated May 29, 2025. (xiii) Incorporated herein by reference to the exhibits to our Form 8-K dated December 29, 2025. 87 SIGNATURES Pursuant to the requirement of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized. AAON, INC. Dated: March 2, 2026 By: /s/ Matthew J. Tobolski Matthew J. Tobolski Chief Executive Officer Dated: March 2, 2026 By: /s/ Rebecca A. Thompson Rebecca A. Thompson Chief Financial Officer 88 Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this report has been signed below by the following persons on behalf of the Registrant and in the capacities and on the dates indicated. Dated: March 2, 2026 /s/ Matthew J. Tobolski Matthew J. Tobolski Chief Executive Officer and Director (principal executive officer) Dated: March 2, 2026 /s/ Rebecca A. Thompson Rebecca A. Thompson Chief Financial Officer (principal financial officer) Dated: March 2, 2026 /s/ Rebecca A. Thompson Rebecca A. Thompson Principal Accounting Officer Dated: March 2, 2026 /s/ Norman H. Asbjornson Norman H. Asbjornson Director Dated: March 2, 2026 /s/ Gary D. Fields Gary D. Fields Director Dated: March 2, 2026 /s/ Angela E. Kouplen Angela E. Kouplen Director Dated: March 2, 2026 /s/ Caron A. Lawhorn Caron A. Lawhorn Director Dated: March 2, 2026 /s/ Stephen O. LeClair Stephen O. LeClair Director Dated: March 2, 2026 /s/ A.H. McElroy II A.H. McElroy II Director Dated: March 2, 2026 /s/ David R. Stewart David R. Stewart Director Dated: March 2, 2026 /s/ Bruce Ware Bruce Ware Director Dated: March 2, 2026 /s/ Luke A. Bomer Luke A. Bomer Secretary 89