On April 5, 2023, Timothy Walsh notified Ecovyst Inc. that he would be resigning from the Board of Directors effective as of immediately prior to the commencement of the Company's 2023 Annual Meeting of Stockholders and that he will not stand for re-election to the Board at the 2023 Annual Meeting. Mr. Walsh, the managing director of CCMP Capital Advisors, has served on Board since 2014. The resignation of Mr. Walsh and his decision to not stand for re-election to the Board was not as a result of or caused by any disagreement with the Company.

The Board has nominated Kevin M. Fogarty, currently a Class I Director, for election at the Company's 2023 Annual Meeting as a Class III Director. On April 5, 2023, Mr. Fogarty submitted a conditional resignation as a Class I Director effective as of immediately prior to the 2023 Annual Meeting. The resignation and nomination of Mr. Fogarty was effected solely for the purpose of reclassifying the members of the Board into three classes of as equal size as possible.