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Koppers Holdings Inc. — DEFA14A Filings

4 DEFA14A filings on record

This page lists all DEFA14A filings submitted to the SEC by Koppers Holdings Inc. (KOP), sorted by most recent first. Each row links to the full filing on EdgarLookup. Koppers Holdings Inc. has filed 4 DEFA14A documents with the SEC since 2015. To view all SEC filings by Koppers Holdings Inc., see the full filings list.

Overview All Filings Financials Insiders
All 10-K 10-K/A 10-Q 144 144/A 3 3/A 4 4/A 424B1 424B3 5 5/A 8-A12B 8-K 8-K/A ARS CERTNYS CORRESP DEF 14A DEFA14A EFFECT POS AM POSASR PRE 14A S-1 S-1/A S-3 S-3/A S-3ASR S-4 S-4/A S-8 SC 13G SC 13G/A SCHEDULE 13G SCHEDULE 13G/A UPLOAD
Form Description Accession Number Filed Period
DEFA14A DEFA14A 0001193125-25-079158 Apr 11, 2025 —
DEFA14A DEFA14A 0001193125-21-120964 Apr 19, 2021 —
DEFA14A DEFA14A 0001193125-21-120961 Apr 19, 2021 —
DEFA14A DEFA14A 0001193125-20-119211 Apr 24, 2020 —