X0306 4 2022-08-08 0 0001708035 Ecovyst Inc. ECVT 0001372939 CCMP Capital, LP C/O CCMP CAPITAL ADVISORS, LP 200 PARK AVENUE, SUITE 1700 NEW YORK NY 10166 0 0 1 0 0001620042 Quartz Co-Invest, L.P. C/O CCMP CAPITAL ADVISORS, LP 200 PARK AVENUE, SUITE 1700 NEW YORK NY 10166 0 0 1 0 0001718021 CCMP Co-Invest III A GP, LLC C/O CCMP CAPITAL ADVISORS, LP 200 PARK AVENUE, SUITE 1700 NEW YORK NY 10166 0 0 1 0 Common Stock 2022-08-08 4 S 0 6162144 8.3563 D 15910316 I By CCMP Capital Investors III, L.P. Common Stock 2022-08-08 4 S 0 624593 8.3563 D 1612671 I By CCMP Capital Investors III (Employee), L.P. Common Stock 2022-08-08 4 S 0 1878698 8.3563 D 4850719 I CCMP Capital Investors III (AV-7), L.P. Common Stock 2022-08-08 4 S 0 106288 8.3563 D 274433 I CCMP Capital Investors III (AV-8), L.P. Common Stock 2022-08-08 4 S 0 2124864 8.3563 D 5486308 I CCMP Capital Investors III (AV-9), L.P. Common Stock 2022-08-08 4 S 0 139226 8.3563 D 359473 I CCMP Capital Investors III (AV-10), L.P. Common Stock 2022-08-08 4 S 0 1964217 8.3563 D 5071524 I Quartz Co-Invest L.P. Common Stock 2022-08-10 4 S 0 924316 8.3563 D 14986000 I By CCMP Capital Investors III, L.P. Common Stock 2022-08-10 4 S 0 93689 8.3563 D 1518982 I By CCMP Capital Investors III (Employee), L.P. Common Stock 2022-08-10 4 S 0 281805 8.3563 D 4568914 I CCMP Capital Investors III (AV-7), L.P. Common Stock 2022-08-10 4 S 0 15943 8.3563 D 258490 I CCMP Capital Investors III (AV-8), L.P. Common Stock 2022-08-10 4 S 0 318730 8.3563 D 5167578 I CCMP Capital Investors III (AV-9), L.P. Common Stock 2022-08-10 4 S 0 20884 8.3563 D 338589 I CCMP Capital Investors III (AV-10), L.P. Common Stock 2022-08-10 4 S 0 294633 8.3563 D 4776891 I Quartz Co-Invest L.P. CCMP Capital Associates III, L.P. ("CCMP Capital Associates") is the general partner of each of CCMP Capital Investors III, L.P. ("CCMP Capital Investors"), CCMP Capital Investors III (Employee), L.P. ("CCMP Employee"), CCMP Capital Investors III (AV-7), L.P. ("CCMP AV-7"), CCMP Capital Investors III (AV-8), L.P. ("CCMP AV-8"), CCMP Capital Investors III (AV-9), L.P. ("CCMP AV-9") and CCMP Capital Investors III (AV-10), L.P. ("CCMP AV-10" and, together with CCMP Capital Investors, CCMP Employee, CCMP AV-7, CCMP AV-8 and CCMP AV-9, the "CCMP Capital Funds"). The general partner of CCMP Capital Associates is CCMP Capital Associates III GP, LLC ("CCMP Capital Associates GP"). CCMP Co-Invest III A GP, LLC ("CCMP Co-Invest GP") is the general partner of Quartz Co-Invest, L.P. ("Quartz" and, together with the CCMP Capital Funds, the "CCMP Investors"). CCMP Capital Associates GP and CCMP Co-Invest GP are each wholly owned by CCMP Capital, LP. The general partner of CCMP Capital, LP is CCMP Capital GP, LLC. CCMP Capital GP, LLC ultimately exercises voting and dispositive power over the shares of common stock of Ecovyst Inc. held by the CCMP Investors. As a result, each of CCMP Capital Associates, CCMP Capital Associates GP, CCMP Co-Invest GP, CCMP Capital, LP and CCMP Capital GP, LLC may be deemed to share beneficial ownership with respect to certain of the shares of common stock of Ecovyst Inc. held by the CCMP Investors. Each of the reporting persons disclaims beneficial ownership of these securities except to the extent of its pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. Form 2 of 2. QUARTZ CO-INVEST L.P., By: CCMP Co-Invest III A GP, LLC, its general partner, By: /s/ Mark McFadden, Title: Managing Partner 2022-08-10 CCMP CO-INVEST III A GP, LLC, By: /s/ Mark McFadden, Title: Managing Partner 2022-08-10