Koppers Holdings Inc.
KOPNYSECIK 1315257MaterialsFiscal year ends Dec 31
Reports and events: 257 filings
Newest first, by EDGAR acceptance time (Eastern). Each filing’s page lists its documents on sec.gov and, for 10-K and 10-Q reports, the extracted sections.
What the forms are: 10-K, 10-Q, 8-K, Form 4, DEF 14A, Schedule 13D, Schedule 13G, amendments, accession numbers.
| Filed | Form | What it is | Accession number |
|---|---|---|---|
| 2026-10-2222:28 ET | SCHEDULE 13D/A | Ownership report, active investor, amended | 0000921895-26-002844 |
| 2026-08-0616:05 ET | 10-Q | Quarterly reportPeriod 2026-06-30 | 0001315257-26-000048 |
| 2026-08-0612:14 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0001315257-26-000046 |
| 2026-05-1921:33 ET | SCHEDULE 13D | Ownership report, active investor | 0000921895-26-001441 |
| 2026-05-1113:05 ET | 8-K | 5.02 Departure or appointment of officers or directors; 7.01 Regulation FD disclosure; 9.01 Financial statements and exhibits | 0001315257-26-000041 |
| 2026-05-0816:05 ET | 10-Q | Quarterly reportPeriod 2026-03-31 | 0001315257-26-000038 |
| 2026-05-0813:10 ET | 8-K | 2.02 Results of operations; 2.05 Exit or disposal costs; 5.02 Departure or appointment of officers or directors; 5.07 Shareholder vote results; 7.01 Regulation FD disclosure; 9.01 Financial statements and exhibits | 0001315257-26-000036 |
| 2026-05-0720:18 ET | 8-K/A | 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0001315257-26-000030 |
| 2026-03-2720:30 ET | DEF 14A | Proxy statementPeriod 2026-05-07 | 0001315257-26-000026 |
| 2026-03-1820:45 ET | 8-K/A | 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0001315257-26-000017 |
| 2026-02-2617:17 ET | 10-K | Annual reportPeriod 2025-12-31 | 0001315257-26-000012 |
| 2026-02-2613:59 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0001315257-26-000010 |
| 2026-01-0913:15 ET | 8-K | 5.02 Departure or appointment of officers or directors; 8.01 Other events; 9.01 Financial statements and exhibits | 0001315257-26-000004 |
| 2025-12-0321:35 ET | 8-K/A | 2.05 Exit or disposal costs | 0001315257-25-000014 |
| 2025-11-0717:37 ET | 10-Q | Quarterly reportPeriod 2025-09-30 | 0001315257-25-000012 |
| 2025-11-0713:22 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0001315257-25-000010 |
| 2025-11-0521:35 ET | 8-K | 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0001315257-25-000006 |
| 2025-08-0815:59 ET | 10-Q | Quarterly reportPeriod 2025-06-30 | 0000950170-25-105595 |
| 2025-08-0812:10 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-25-105486 |
| 2025-06-1812:01 ET | 8-K | 1.01 Entry into a material agreement; 2.03 New direct financial obligation; 9.01 Financial statements and exhibits | 0000950170-25-087681 |
| 2025-05-2912:00 ET | 8-K | 5.02 Departure or appointment of officers or directors; 8.01 Other events; 9.01 Financial statements and exhibits | 0000950170-25-078597 |
| 2025-05-0916:21 ET | 10-Q | Quarterly reportPeriod 2025-03-31 | 0000950170-25-067733 |
| 2025-05-0912:19 ET | 8-K | 2.02 Results of operations; 5.02 Departure or appointment of officers or directors; 5.07 Shareholder vote results; 9.01 Financial statements and exhibits | 0000950170-25-067521 |
| 2025-03-2820:30 ET | DEF 14A | Proxy statementPeriod 2025-05-08 | 0000950170-25-046841 |
| 2025-02-2716:53 ET | 10-K | Annual reportPeriod 2024-12-31 | 0000950170-25-028542 |
| 2025-02-2713:33 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-25-028398 |
| 2024-12-1721:31 ET | 8-K | 1.01 Entry into a material agreement; 2.03 New direct financial obligation; 9.01 Financial statements and exhibits | 0001193125-24-280510 |
| 2024-12-0912:58 ET | 8-K | 5.02 Departure or appointment of officers or directors | 0000950170-24-134339 |
| 2024-12-0521:45 ET | 8-K | 2.05 Exit or disposal costs; 9.01 Financial statements and exhibits | 0000950170-24-133737 |
| 2024-11-0816:59 ET | 10-Q | Quarterly reportPeriod 2024-09-30 | 0000950170-24-123804 |
| 2024-11-0813:24 ET | 8-K | 2.02 Results of operations; 2.05 Exit or disposal costs; 9.01 Financial statements and exhibits | 0000950170-24-123708 |
| 2024-08-0816:16 ET | 10-Q | Quarterly reportPeriod 2024-06-30 | 0000950170-24-093561 |
| 2024-08-0812:24 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-24-093360 |
| 2024-05-0318:01 ET | 10-Q | Quarterly reportPeriod 2024-03-31 | 0000950170-24-052678 |
| 2024-05-0312:26 ET | 8-K | 2.02 Results of operations; 5.03 Amendment to articles or bylaws; 5.07 Shareholder vote results; 9.01 Financial statements and exhibits | 0000950170-24-052494 |
| 2024-05-0220:15 ET | 8-K/A | 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0000950170-24-052134 |
| 2024-04-1512:06 ET | 8-K | 1.01 Entry into a material agreement; 2.03 New direct financial obligation; 9.01 Financial statements and exhibits | 0001193125-24-095544 |
| 2024-04-0220:34 ET | DEF 14A | Proxy statementPeriod 2024-05-02 | 0001193125-24-084813 |
| 2024-02-2817:09 ET | 10-K | Annual reportPeriod 2023-12-31 | 0000950170-24-021787 |
| 2024-02-2813:17 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-24-021675 |
| 2024-02-1321:30 ET | 8-K | 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0000950170-24-014607 |
| 2024-01-0221:30 ET | 8-K | 5.02 Departure or appointment of officers or directors; 8.01 Other events; 9.01 Financial statements and exhibits | 0000950170-24-000286 |
| 2023-11-0316:25 ET | 10-Q | Quarterly reportPeriod 2023-09-30 | 0000950170-23-058640 |
| 2023-11-0312:21 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-23-058530 |
| 2023-10-1212:46 ET | 8-K | 1.01 Entry into a material agreement; 2.03 New direct financial obligation; 9.01 Financial statements and exhibits | 0001193125-23-254683 |
| 2023-09-1412:32 ET | 8-K | 7.01 Regulation FD disclosure; 9.01 Financial statements and exhibits | 0000950170-23-048041 |
| 2023-08-0320:34 ET | 8-K | 5.03 Amendment to articles or bylaws; 9.01 Financial statements and exhibits | 0000950170-23-038090 |
| 2023-08-0316:07 ET | 10-Q | Quarterly reportPeriod 2023-06-30 | 0000950170-23-037727 |
| 2023-08-0312:27 ET | 8-K | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-23-037613 |
| 2023-05-0515:55 ET | 10-Q | Quarterly reportPeriod 2023-03-31 | 0000950170-23-018172 |
Source: SEC EDGAR, the company’s filing index. Last ingested by Listed: Oct 24, 2026, 15:11 ET. Listed shows no prices and gives no investment advice.