Koppers Holdings Inc. Declares Quarterly Cash Dividend

PITTSBURGH, May 7, 2026 — Koppers Holdings Inc. (NYSE: KOP), an integrated global provider of treated wood products, wood treatment chemicals, and carbon compounds, today announced that its Board of Directors has declared a quarterly cash dividend of $0.09 per share of Koppers common stock. The dividend is payable on June 15, 2026, to shareholders of record as of the close of trading on May 29, 2026.

Koppers expects to pay regular quarterly dividends, with future declarations subject to approval by its Board of Directors and the Board's determination that the declaration of dividends remains in the best interests of Koppers and its shareholders. The decision of whether to pay future dividends and the amount of any such dividends will be based on the Company's financial position, results of operations, cash flows, capital requirements, the requirements of applicable law and any other factors the Board of Directors may deem relevant.

About Koppers

Koppers (NYSE: KOP) is an integrated global provider of essential treated wood products, wood preservation technologies and carbon compounds. Our team of approximately 1,850 employees create, protect and preserve key elements of our global infrastructure – including railroad crossties, utility poles, outdoor wooden structures, and production feedstocks for steel, aluminum and construction materials, among others – applying decades of industry-leading expertise while constantly innovating to anticipate the needs of tomorrow. Together we are providing safe and sustainable solutions to enable rail transportation, keep power flowing, and create spaces of enjoyment for people everywhere. Protecting What Matters, Preserving The Future. Learn more at Koppers.com.

Inquiries from the media should be directed to Ms. Jessica Franklin Black at [email protected] or 412-227-2025. Inquiries from the investment community should be directed to Ms. Quynh McGuire at [email protected] or 412-227-2049.