As Of	Filer	Filing¹	For·On·As	Docs:Size	Issuer		Filing Agent

  3/9/23  Feehan Michael                    4          Officer²    1:5K   Ecovyst Inc.                      Donnelley … Solutions/FA 
  3/9/23  Coxon Robert                      4          Director²   1:4K   Ecovyst Inc.                      Donnelley … Solutions/FA 
  3/7/23  Vann Kyle D                       4          Director²   1:4K   Ecovyst Inc.                      Donnelley … Solutions/FA 
  3/7/23  CCMP Capital, LP                  4          10% Owner²  1:16K  Ecovyst Inc.                      Donnelley Fin’l S… 06/FA 
          CCMP Co-Invest III A GP, LLC
          Quartz Co-Invest, L.P.
  3/7/23  CCMP Capital, LP                  4          10% Owner²  1:27K  Ecovyst Inc.                      Donnelley Fin’l S… 06/FA 
          CCMP Capital Associates III GP, LLC
          CCMP Capital Associates III, L.P.
          CCMP Capital GP, LLC
          CCMP Capital Investors III (AV-7), L.P.
          CCMP Capital Investors III (AV-8), L.P.
          CCMP Capital Investors III (AV-9), L.P.
          CCMP Capital Investors III (AV-10), L.P.
          CCMP Capital Investors III (Employee), L.P.
          CCMP Capital Investors III, L.P.

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¹	Filing/Form Type:
	4	Statement of Changes in Beneficial Ownership of Securities by an Insider — Form 4 { The Filer is an Insider² of the Issuer }.
²	Insider:  The Filer is a Director, Officer, 10% Owner and/or Other “insider” of the Issuer.