<SEC-DOCUMENT>0001193125-23-151964-index.html : 20230524 <SEC-HEADER>0001193125-23-151964.hdr.sgml : 20230524 <ACCEPTANCE-DATETIME>20230523173709 ACCESSION NUMBER: 0001193125-23-151964 CONFORMED SUBMISSION TYPE: 424B7 PUBLIC DOCUMENT COUNT: 4 FILED AS OF DATE: 20230524 DATE AS OF CHANGE: 20230523 FILER: COMPANY DATA: COMPANY CONFORMED NAME: Ecovyst Inc. CENTRAL INDEX KEY: 0001708035 STANDARD INDUSTRIAL CLASSIFICATION: CHEMICALS & ALLIED PRODUCTS [2800] IRS NUMBER: 813406833 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: 424B7 SEC ACT: 1933 Act SEC FILE NUMBER: 333-255514 FILM NUMBER: 23949973 BUSINESS ADDRESS: STREET 1: 300 LINDENWOOD DRIVE CITY: MALVERN STATE: PA ZIP: 19355 BUSINESS PHONE: 484-617-1200 MAIL ADDRESS: STREET 1: 300 LINDENWOOD DRIVE CITY: MALVERN STATE: PA ZIP: 19355 FORMER COMPANY: FORMER CONFORMED NAME: PQ Group Holdings Inc. DATE OF NAME CHANGE: 20170531 </SEC-HEADER> <DOCUMENT> <TYPE>424B7 <SEQUENCE>1 <FILENAME>d491404d424b7.htm <DESCRIPTION>424B7 <TEXT> Document 1 - file: d491404d424b7.htm
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