Koppers Holdings Inc. — DEF 14A Filings
20 DEF 14A filings on record
This page lists all DEF 14A 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 20 DEF 14A documents with the SEC since 2015. To view all SEC filings by Koppers Holdings Inc., see the full filings list.
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 |
|---|---|---|---|---|
| DEF 14A | DEF 14A | 0001315257-26-000026 | Mar 27, 2026 | May 7, 2026 |
| DEF 14A | DEF 14A | 0000950170-25-046841 | Mar 28, 2025 | May 8, 2025 |
| DEF 14A | DEF 14A | 0001193125-24-084813 | Apr 2, 2024 | May 2, 2024 |
| DEF 14A | DEF 14A | 0001193125-23-089616 | Apr 3, 2023 | — |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-22-095129 | Apr 4, 2022 | May 5, 2022 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-21-106380 | Apr 5, 2021 | May 6, 2021 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-20-090990 | Mar 30, 2020 | May 6, 2020 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-19-094575 | Apr 1, 2019 | May 2, 2019 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-18-102060 | Mar 29, 2018 | May 1, 2018 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-17-110180 | Apr 4, 2017 | May 4, 2017 |
| DEF 14A | DEF 14A | 0001193125-16-530845 | Apr 5, 2016 | May 5, 2016 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-15-120001 | Apr 6, 2015 | May 7, 2015 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-14-118543 | Mar 27, 2014 | May 2, 2014 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-13-129373 | Mar 27, 2013 | May 2, 2013 |
| DEF 14A | NOTICE & PROXY | 0001193125-12-137538 | Mar 28, 2012 | May 3, 2012 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-11-082945 | Mar 30, 2011 | May 4, 2011 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-10-073423 | Mar 31, 2010 | May 5, 2010 |
| DEF 14A | 2009 NOTICE & PROXY STATEMENT | 0001193125-09-070707 | Apr 1, 2009 | May 6, 2009 |
| DEF 14A | NOTICE & PROXY STATEMENT | 0001193125-08-075343 | Apr 4, 2008 | May 7, 2008 |
| DEF 14A | NOTICE & PROXY | 0001193125-07-070592 | Mar 30, 2007 | May 2, 2007 |