KOPPERS HOLDINGS INC. Auditor
The independent registered public accounting firm that signed the audit report in each annual report on Form 10-K, newest first. PCAOB firm ID and the internal-control attestation are as tagged on the cover from fiscal 2021; earlier rows come from the signed report text.
- 2026-02-26: Fiscal year end 2025-12-31; Auditor KPMG LLP; PCAOB firm ID 185; Location Pittsburgh, Pennsylvania (US Firm).
- 2025-02-27: Fiscal year end 2024-12-31; Auditor KPMG LLP; PCAOB firm ID 185; Location Pittsburgh, Pennsylvania (US Firm).
- 2024-02-28: Fiscal year end 2023-12-31; Auditor KPMG LLP; PCAOB firm ID 185; Location Pittsburgh, Pennsylvania (US Firm).
- 2023-02-27: Fiscal year end 2022-12-31; Auditor KPMG LLP; PCAOB firm ID 185; Location Pittsburgh, Pennsylvania (US Firm).
| Filed | Fiscal year end | Auditor | PCAOB firm ID | Location | Internal-control attestation |
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| 2026-02-26 | 2025-12-31 | KPMG LLP | 185 | Pittsburgh, Pennsylvania (US Firm) | Yes |
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| 2025-02-27 | 2024-12-31 | KPMG LLP | 185 | Pittsburgh, Pennsylvania (US Firm) | Yes |
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| 2024-02-28 | 2023-12-31 | KPMG LLP | 185 | Pittsburgh, Pennsylvania (US Firm) | Yes |
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| 2023-02-27 | 2022-12-31 | KPMG LLP | 185 | Pittsburgh, Pennsylvania (US Firm) | Yes |
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| 2022-02-23 | 2021-12-31 | KPMG LLP | 185 | Pittsburgh, Pennsylvania (US Firm) | Yes |
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| 2021-02-24 | 2020-12-31 | KPMG LLP | | Pittsburgh, Pennsylvania | Yes |
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| 2020-02-27 | 2019-12-31 | KPMG LLP | | Pittsburgh, Pennsylvania | |
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| 2019-03-01 | 2018-12-31 | KPMG LLP | | Pittsburgh, Pennsylvania | |
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| 2018-02-27 | 2017-12-31 | KPMG LLP | | Pittsburgh, Pennsylvania | |
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| 2017-02-24 | 2016-12-31 | KPMG LLP | | Pittsburgh, Pennsylvania | |
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| 2016-02-29 | 2015-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2015-03-02 | 2014-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2014-03-03 | 2013-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2013-02-25 | 2012-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2012-02-27 | 2011-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2011-02-22 | 2010-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2010-02-19 | 2009-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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| 2009-02-20 | 2008-12-31 | ERNST & YOUNG LLP | | Pittsburgh, Pennsylvania | |
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