AAON, INC.

(a) Evaluation of Disclosure Controls and Procedures

As of the end of the period covered by this Quarterly Report on Form 10-Q, we carried out an evaluation, under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer with the oversight of the Audit Committee, regarding the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rule 13a-15(e) promulgated under the Securities Exchange Act of 1934, as amended). Based upon that evaluation, our Chief Executive Officer and Chief Financial Officer have concluded, as of the end of the period covered by this Quarterly Report, due to the existence of the material weakness in our internal control over financial reporting described below, our disclosure controls and procedures were not effective to ensure that the information required to be disclosed in the reports that we file or submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to management as appropriate to allow timely decisions regarding required disclosure.

Notwithstanding such material weakness in our internal control over financial reporting, Company management, including our Chief Executive Officer and Chief Financial Officer, concluded that our consolidated financial statements in this quarterly report present fairly, in all material respects, our financial position, results of operations and cash flows for the periods presented, in conformity with US GAAP.

Material Weakness in Internal Control over Financial Reporting

A material weakness is a deficiency, or combination of deficiencies, in internal control over financial reporting, such

that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will

not be prevented or detected on a timely basis.

We did not maintain an effective control environment based on the criteria established in the Committee of Sponsoring Organizations of the Treadway Commissions (“COSO”) in the 2013 Internal Control-Integrated Framework (“2013 Framework”) and identified deficiencies in the principles associated with the Control Activities and Communication component of the 2013 Framework that constitute a material weakness, either individually or in the aggregate. The Company had previously identified control deficiencies that did not rise to the level of a material weakness related to processes associated with our ERP implementation in 2025 and driven by the increased growth and volume of the business. As part of our efforts to strengthen our internal control and remediate prior deficiencies, we identified certain errors, which have been corrected. As a result, we have restated our Q1 and Q2 Form 10Qs and identified the following material weakness, which exists as of September 30, 2026:

•We did not design and maintain adequate controls within the BASX-branded revenue process that resulted in a material weakness, either individually or in the aggregate. Primarily, the identified deficiencies included controls over the assignment of costs to the appropriate projects to ensure proper revenue recognition.

We did not design and maintain adequate controls over certain aspects of the financial statement close process related to BASX-branded revenue. Specifically, controls related to account reconciliation, analysis and review related to key financial statement accounts did not operate timely and with complete and accurate information.

Management’s Plan for Remediation

Over the past few years, our business has been in transition as we are expanding our internal infrastructure to support future growth and more complex business operations. This overall growth and increase in complexity of our business and its operations has strained our control structure that supports the effective operation of internal controls over accounting and financial reporting processes. We are committed to maintaining strong internal control over financial reporting. Management, with the oversight of the Audit Committee of the Board of Directors is taking comprehensive actions to remediate the material weakness described above. Our remediation plan includes the following:

•We are enhancing the design of existing controls and implementing new controls related to revenue, the financial close and reporting process. These include improvements to the tracking of costs and to the timely review of estimated costs to complete projects, including assessing our information technology systems for opportunities to reduce the reliance on manual controls over financial reporting.

•We are updating documentation, expanding education and training, and ensuring that controls are executed and reviewed for accurate reporting.

The material weakness will not be considered remediated until the new and redesigned controls operate for a sufficient period of time and management has concluded, through testing, that these controls are operating effectively. We believe the above measures, along with enhanced senior leadership’s oversight and monitoring of the internal control environment, will remediate the control deficiencies identified and strengthen our internal control over financial reporting. As we continue to evaluate and work to remediate the control deficiencies that gave rise to the material weakness, we may determine that additional measures are required to address the control deficiencies or that we need to modify or otherwise adjust the remediation measures described above. We will continue to assess the effectiveness of our remediation efforts in connection with our evaluation of our internal control over financial reporting.

(b) Changes in Internal Control over Financial Reporting

Other than described above, 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.

PART II – OTHER INFORMATION

See Note 19 of the Consolidated Financial Statements.