# Koppers Holdings Inc.: Form SCHEDULE 13D/A, filed Oct 22, 2026

- Company: [Koppers Holdings Inc.](/companies/kop.md) (CIK 1315257)
- Form: SCHEDULE 13D/A
- Filed: 2026-10-22
- Accepted by EDGAR: Oct 22, 2026, 18:28 ET
- Period: not reported
- Accession: 0000921895-26-002844
- Inline XBRL: no
- Main document: https://www.sec.gov/Archives/edgar/data/1315257/000092189526002844/xslSCHEDULE_13D_X02/primary_doc.xml
- All documents and exhibits: https://www.sec.gov/Archives/edgar/data/1315257/000092189526002844/

## Sections

Sections are extracted only from 10-K and 10-Q reports. Read this filing’s documents on sec.gov. https://www.sec.gov/Archives/edgar/data/1315257/000092189526002844/xslSCHEDULE_13D_X02/primary_doc.xml

Filed Oct 22, 2026.
Source: SEC EDGAR, the filing index for accession 0000921895-26-002844. Last ingested by Listed: Oct 30, 2026, 12:04 ET. No prices; not investment advice.