X0202 SCHEDULE 13G/A 0001172661-25-004860 0001164833 XXXXXXXX LIVE 4 Common stock, par value $0.01 per share 03/31/2026 0001708035 Ecovyst Inc. 27923Q109 600 LEE ROAD, SUITE 200 WAYNE PA 19087 Rule 13d-1(b) Hotchkis and Wiley Capital Management, LLC DE 4720982.00 0.00 5413862.00 0.00 5413862.00 N 4.90 IA Ecovyst Inc. 600 LEE ROAD, SUITE 200, WAYNE, PA, 19087 Hotchkis and Wiley Capital Management, LLC 601 S. Figueroa Street, 39th Fl, Los Angeles, CA 90017 Delaware N IA 5,413,862 4.90% 4,720,982 0 5,413,862 0 Note that certain of HWCM's clients have retained voting power over the Common Shares that they beneficially own. Accordingly, HWCM has the power to dispose of more Common Shares than it can vote. N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Hotchkis and Wiley Capital Management, LLC Tina H. Kodama 05/08/2026