Ecovyst Inc. 10-Q

ITEM 4. CONTROLS AND PROCEDURES. Evaluation of Disclosure Controls and Procedures Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of our disclosure controls and procedures as of September 30, 2025, the end of the period covered by this Quarterly Report on Form 10-Q. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (“Exchange Act”), means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company’s management, including its principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on that evaluation, our Chief Executive Officer and Chief Financial Officer concluded that, a s of such date, our disclosure controls and procedures were not effective due to the material weakness in the Company’s internal control over financial reporting, as described below and in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2024. Notwithstanding the conclusion that the Company’s disclosure controls and procedures were not effective as of September 30, 2025 , our Chief Executive Officer and Chief Financial Officer believe that the Company’s unaudited condensed consolidated financial statements included in this Quarterly Report are fairly stated in all material respects in accordance with U.S. generally accepted accounting principles for each of the periods presented. Material Weakness in Internal Control over Financial Reporting A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of a company’s annual or interim financial statements will not be prevented or detected on a timely basis. A material weakness in relation to the Company’s controls over the accounting of its Zeolyst Joint Venture was identified as of December 31, 2024 and continues to exist as of September 30, 2025. The Company does not have sufficient controls designed to ensure its proportionate share of the earnings from the Zeolyst Joint Venture, an equity method investee underlying the Company’s financial statements, were completely, accurately, and timely recorded. This material weakness resulted in immaterial adjustments to our equity in net income from affiliated companies and investments in affiliated companies as of and for the fiscal years ended December 31, 2024, 2023 and 2022, and for the interim periods contained within those fiscal years. This material weakness could result in a material misstatement of our equity in net income from affiliated companies and investments in affiliated companies that would not be prevented or detected on a timely basis. Plan for Remediation of Material Weakness We commenced a remediation plan with respect to this material weakness. In carrying out our plan, management modified existing key controls and implemented new key controls to ensure our proportionate share of the earnings from the Zeolyst Joint Venture are completely, accurately, and timely recorded in our financial statements. This material weakness will not be considered remediated until the applicable controls operate for a sufficient period of time and management has concluded, through testing, that these controls are operating effectively. We expect that the material weakness will be remediated before the end of 2025. Changes in Internal Control Over Financial Reporting No changes in our internal control over financial reporting occurred during the quarter ended September 30, 2025 that materially affected, or which are reasonably likely to materially affect, our internal control over financial reporting. 50 Table of Contents PART II — OTHER INFORMATION