Koppers Holdings Inc. 10-K

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA Koppers Holdings Inc. INDEX TO CONSOLIDATED FINANCIAL STATEMENTS Page Management’s Report on Internal Control Over Financial Reporting 38 Report of Independent Registered Public Accounting Firm 39 Report of Independent Registered Public Accounting Firm 40 Consolidated Statement of Operations 42 Consolidated Statement of Comprehensive Income 42 Consolidated Balance Sheet 43 Consolidated Statement of Cash Flows 44 Consolidated Statement of Shareholders’ Equity 45 Notes to Consolidated Financial Statements 46 37 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report MANAGEMENT’S REPORT ON INTERNAL CONTROL OVER FINANCIAL REPORTING The management of Koppers Holdings Inc. is responsible for establishing and maintaining adequate internal control over financial reporting. Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external reporting purposes in accordance with accounting principles generally accepted in the United States of America. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Management has assessed the effectiveness of Koppers Holdings Inc.’s internal control over financial reporting as of December 31, 2025. In making this assessment, management has utilized the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control – Integrated Framework (2013 Framework). Management concluded that based on its assessment, Koppers Holdings Inc.’s internal control over financial reporting was effective as of December 31, 2025. The effectiveness of Koppers Holdings Inc.’s internal control over financial reporting as of December 31, 2025, has been audited by KPMG LLP, the independent registered public accounting firm that also audited the consolidated financial statements included in this annual report, as stated in their attestation report which appears on the following page. February 26, 2026 / S / L EROY M. B ALL Leroy M. Ball Chief Executive Officer /s/ B RADLEY A. P EARCE Bradley A. Pearce Interim Chief Financial Officer and Chief Accounting Officer 38 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Report of Independent Registered Public Accounting Firm To the Shareholders and Board of Directors Koppers Holdings Inc.: Opinion on Internal Control Over Financial Reporting We have audited Koppers Holdings Inc. and subsidiaries' (the Company) internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated balance sheets of the Company as of December 31, 2025 and December 31, 2024, the related consolidated statements of operations, comprehensive income, shareholders’ equity, and cash flows for each of the years in the three-year period ended December 31, 2025, and the related notes and financial statement schedule II (collectively, the consolidated financial statements), and our report dated February 26, 2026 expressed an unqualified opinion on those consolidated financial statements. Basis for Opinion The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audit also included performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion. Definition and Limitations of Internal Control Over Financial Reporting A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate. /s/ KPMG LLP Pittsburgh, Pennsylvania February 26, 2026 39 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Report of Independent Registered Public Accounting Firm To the Shareholders and Board of Directors Koppers Holdings Inc.: Opinion on the Consolidated Financial Statements We have audited the accompanying consolidated balance sheets of Koppers Holdings Inc. and subsidiaries (the Company) as of December 31, 2025 and December 31, 2024, the related consolidated statements of operations, comprehensive income, shareholders’ equity, and cash flows for each of the years in the three-year period ended December 31, 2025, and the related notes and financial statement schedule II (collectively, the consolidated financial statements). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and December 31, 2024, and the results of its operations and its cash flows for each of the years in the three-year period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles. We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission, and our report dated February 26, 2026 expressed an unqualified opinion on the effectiveness of the Company’s internal control over financial reporting. Basis for Opinion These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these consolidated financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion. Critical Audit Matter The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of a critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates. Assessment of the carrying value of Goodwill in the Utility Products Reporting Unit As described in Note 13 to the consolidated financial statements, the Company’s goodwill balance as of December 31, 2025 was $329.4 million, of which $116.7 million was related to the Utility Products reporting unit. The Company performs goodwill impairment testing at the reporting unit level annually or more frequently if a change in circumstances or the occurrence of events indicates that a potential impairment exists. The Company uses a combination of an income approach, using a discounted cash flow methodology, and a market approach in its annual goodwill impairment assessment. We identified the assessment of the carrying value of goodwill for the Utility Products reporting unit as a critical audit matter. Significant auditor judgment was required to evaluate the Company’s estimate of fair value of the Utility Products reporting unit, which was developed, in part, using a discounted cash flow model. Specifically, the key assumptions used in the reporting unit's discounted cash flow model are forecasted revenue growth rates and forecasted EBITDA margins within the forecasted cash flows, and the discount rate, as changes to those assumptions could have a significant effect on the Company’s assessment of the impairment of the goodwill. The following are the primary procedures we performed to address this critical audit matter. We evaluated the design and tested the operating effectiveness of certain internal controls related to the Company’s goodwill impairment assessment process. This included controls over the development of the forecasted revenue growth rates, forecasted 40 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report EBITDA margins, and discount rate assumptions. We compared the Company’s historical forecasted revenue growth rates and forecasted EBITDA margins to actual results to assess the Company’s ability to accurately forecast. We evaluated the Company’s forecasted revenue growth rates and forecasted EBITDA margins by comparing the forecasts to historical results and to forecasted information included in external industry reports. We also involved valuation professionals with specialized skills and knowledge, who assisted in evaluating the Company’s discount rate, by comparing it against a discount rate that was independently developed using publicly available third-party market data for comparable entities. /s/ KPMG LLP We have served as the Company’s auditor since 2016. Pittsburgh, Pennsylvania February 26, 2026 41 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report KOPPERS HOLDINGS INC. CONSOLIDATED STATEMENT OF OPERATIONS Year Ended December 31, 2025 2024 2023 (Dollars in millions, except share and per share amounts) Net sales $ 1,879.3 $ 2,092.1 $ 2,154.2 Cost of sales 1,431.5 1,669.5 1,729.7 Depreciation and amortization 73.6 67.5 57.0 Selling, general and administrative 154.9 179.3 174.1 Impairment and restructuring 51.9 16.9 0.0 (Gain) loss on sale of assets ( 0.4 ) 10.7 ( 1.8 ) Operating profit 167.8 148.2 195.2 Other income, net 6.6 1.3 0.4 Interest expense 66.1 76.2 71.0 Loss on pension settlement 27.1 4.0 0.0 Income before income taxes 81.2 69.3 124.6 Income tax provision 25.2 20.7 34.8 Net income 56.0 48.6 89.8 Net income (loss) attributable to noncontrolling interests 0.0 ( 3.8 ) 0.6 Net income attributable to Koppers $ 56.0 $ 52.4 $ 89.2 Earnings per common share attributable to Koppers common shareholders: Basic $ 2.82 $ 2.54 $ 4.28 Diluted 2.74 2.46 4.14 Weighted average shares outstanding (in thousands): Basic 19,855 20,659 20,835 Diluted 20,405 21,291 21,539 KOPPERS HOLDINGS INC. CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME Year Ended December 31, 2025 2024 2023 (Dollars in millions) Net income $ 56.0 $ 48.6 $ 89.8 Changes in other comprehensive income (loss): Currency translation adjustment 32.6 ( 30.3 ) 6.9 Cash flow hedges, net of tax of $( 1.1 ), $ 0.5 and $ 0.8 2.4 ( 1.4 ) ( 2.7 ) Pension adjustments, net of tax of $( 7.8 ), $ 0.0 and $( 1.1 ) 24.2 ( 0.1 ) 4.2 Total comprehensive income 115.2 16.8 98.2 Comprehensive income (loss) attributable to noncontrolling interests 0.0 ( 3.8 ) 0.5 Comprehensive income attributable to Koppers $ 115.2 $ 20.6 $ 97.7 The accompanying notes are an integral part of these consolidated financial statements. 42 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report KOPPERS HOLDINGS INC. CONSOLIDATED BALANCE SHEET December 31, 2025 2024 (Dollars in millions, except share and per share amounts) Assets Cash and cash equivalents $ 38.0 $ 43.9 Accounts receivable, net of allowance of $ 7.0 and $ 6.9 158.7 191.8 Inventories, net 411.2 404.6 Derivative contracts 31.5 1.5 Other current assets 29.3 38.8 Total current assets 668.7 680.6 Property, plant and equipment, net 650.9 660.8 Goodwill 329.4 317.1 Intangible assets, net 106.7 119.0 Operating lease right-of-use assets 102.9 89.8 Deferred tax assets 7.0 8.4 Other assets 21.2 14.5 Total assets $ 1,886.8 $ 1,890.2 Liabilities Accounts payable $ 122.4 $ 179.1 Accrued liabilities 72.6 115.1 Current operating lease liabilities 27.2 26.7 Current maturities of long-term debt 4.9 4.9 Total current liabilities 227.1 325.8 Long-term debt 914.3 925.9 Operating lease liabilities 76.1 64.4 Accrued post-retirement benefits 13.7 14.9 Deferred tax liabilities 43.7 25.9 Other long-term liabilities 37.6 44.3 Total liabilities 1,312.5 1,401.2 Commitments and contingent liabilities (Note 17) Equity Senior Convertible Preferred Stock, $ 0.01 par value per share; 10,000,000 shares authorized; no shares issued 0.0 0.0 Common Stock, $ 0.01 par value per share; 80,000,000 shares authorized; 26,213,052 and 25,761,084 shares issued 0.3 0.3 Additional paid-in capital 332.4 317.2 Retained earnings 539.4 490.3 Accumulated other comprehensive loss ( 61.4 ) ( 120.6 ) Treasury stock, at cost, 6,757,247 and 5,480,230 shares ( 236.7 ) ( 198.5 ) Total Koppers shareholders’ equity 574.0 488.7 Noncontrolling interests 0.3 0.3 Total equity 574.3 489.0 Total liabilities and equity $ 1,886.8 $ 1,890.2 The accompanying notes are an integral part of these consolidated financial statements. 43 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report KOPPERS HOLDINGS INC. CONSOLIDATED STATEMENT OF CASH FLOWS Year Ended December 31, 2025 2024 2023 (Dollars in millions) Cash provided by (used in) operating activities: Net income $ 56.0 $ 48.6 $ 89.8 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 73.6 67.5 57.0 Depreciation in impairment and restructuring 19.7 4.4 0.0 Stock-based compensation 13.8 20.8 17.3 Change in derivative contracts ( 34.2 ) 7.9 ( 0.9 ) Non-cash interest expense 3.7 3.3 4.9 (Gain) loss on sale of assets ( 1.4 ) 10.0 ( 2.0 ) Insurance proceeds ( 2.2 ) ( 1.0 ) ( 1.7 ) Pension settlement 27.1 0.0 0.0 Deferred income taxes 11.3 2.8 5.7 Change in other liabilities 5.0 ( 2.6 ) 0.2 Cloud-based software implementation costs, net ( 5.6 ) 0.0 0.0 Other - net ( 2.9 ) 1.9 2.2 Changes in working capital: Accounts receivable 30.9 8.1 14.9 Inventories 10.4 ( 6.3 ) ( 37.2 ) Accounts payable ( 57.2 ) ( 19.4 ) ( 0.4 ) Accrued liabilities ( 33.1 ) ( 19.2 ) ( 2.4 ) Other working capital 7.6 ( 7.4 ) ( 1.3 ) Net cash provided by operating activities 122.5 119.4 146.1 Cash (used in) provided by investing activities: Capital expenditures ( 55.0 ) ( 77.4 ) ( 120.5 ) Acquisitions ( 20.7 ) ( 99.3 ) 0.0 Insurance proceeds 2.2 1.0 1.7 Sale of assets 5.2 2.4 2.8 Sale of business and divestitures 4.8 0.0 0.0 Other investing activities ( 9.2 ) 0.0 0.0 Net cash used in investing activities ( 72.7 ) ( 173.3 ) ( 116.0 ) Cash provided by (used in) financing activities: Borrowings of credit facility 558.3 706.5 1,032.5 Repayments of credit facility ( 566.1 ) ( 712.1 ) ( 896.4 ) Borrowings of long-term debt 0.0 100.0 388.0 Repayments of long-term debt ( 4.9 ) ( 5.7 ) ( 501.0 ) Issuances of Common Stock 1.4 5.3 9.9 Repurchases of Common Stock ( 38.2 ) ( 50.8 ) ( 20.1 ) Payment of debt issuance costs ( 2.6 ) ( 1.6 ) ( 5.3 ) Dividends paid ( 6.4 ) ( 5.9 ) ( 5.0 ) Net cash (used in) provided by financing activities ( 58.5 ) 35.7 2.6 Effect of exchange rate changes on cash 2.8 ( 4.4 ) 0.5 Net (decrease) increase in cash and cash equivalents ( 5.9 ) ( 22.6 ) 33.2 Cash and cash equivalents at beginning of period 43.9 66.5 33.3 Cash and cash equivalents at end of period $ 38.0 $ 43.9 $ 66.5 Supplemental disclosure of non-cash investing and financing activities: Right-of-use assets obtained in exchange for new operating lease liabilities $ 39.2 $ 23.9 $ 26.6 Accrued capital expenditures 1.7 2.2 5.6 Non-cash consideration for sale of assets and acquisition 0.6 2.7 0.0 Supplemental disclosure - Cash paid during the year for: Interest $ 63.5 $ 78.5 $ 70.0 Income taxes 9.4 27.6 34.3 The accompanying notes are an integral part of these consolidated financial statements. 44 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report KOPPERS HOLDINGS INC. CONSOLIDATED STATEMENT OF SHAREHOLDERS’ EQUITY Year Ended December 31, 2025 2024 2023 (Dollars in millions, except per share amounts) Senior Convertible Preferred Stock Balance at beginning and end of year $ 0.0 $ 0.0 $ 0.0 Common Stock Balance at beginning of year 0.3 0.3 0.2 Issuance of common stock 0.0 0.0 0.1 Balance at end of year 0.3 0.3 0.3 Additional paid-in capital Balance at beginning of year 317.2 291.1 263.9 Employee stock plans 13.8 20.8 17.3 Issuance of common stock 1.4 5.3 9.9 Balance at end of year 332.4 317.2 291.1 Retained earnings Balance at beginning of year 490.3 444.0 360.2 Net income attributable to Koppers 56.0 52.4 89.2 Common Stock dividends ($ 0.32 , $ 0.28 and $ 0.24 per share) ( 6.9 ) ( 6.1 ) ( 5.4 ) Balance at end of year 539.4 490.3 444.0 Accumulated other comprehensive loss Currency translation adjustment: Balance at beginning of year ( 79.2 ) ( 48.9 ) ( 55.9 ) Change in currency translation adjustment 32.6 ( 30.3 ) 7.0 Balance at end of year ( 46.6 ) ( 79.2 ) ( 48.9 ) Cash flow hedges: Balance at beginning of year ( 2.3 ) ( 0.9 ) 1.8 Reclassification of cash flow hedges to expense, net of tax of $( 0.7 ), $ 0.3 and $ 0.5 1.5 ( 0.9 ) ( 1.5 ) Cash flow hedges, net of tax of $( 0.4 ), $ 0.2 and $ 0.3 0.9 ( 0.5 ) ( 1.2 ) Balance at end of year 0.1 ( 2.3 ) ( 0.9 ) Unrecognized pension prior service cost (benefit): Balance at beginning and end of year ( 0.5 ) ( 0.5 ) ( 0.5 ) Unrecognized pension net loss: Balance at beginning of year ( 38.6 ) ( 38.5 ) ( 42.7 ) Reclassification of unrecognized pension net loss to expense, net of tax of $( 6.9 ), $ 1.4 and $ 0.4 20.8 4.1 1.2 Revaluation of unrecognized pension net gain (loss), net of tax of $( 0.9 ), $( 1.7 ) and $ 0.7 3.4 ( 4.2 ) 3.0 Balance at end of year ( 14.4 ) ( 38.6 ) ( 38.5 ) Total balance at end of year ( 61.4 ) ( 120.6 ) ( 88.8 ) Treasury stock Balance at beginning of year ( 198.5 ) ( 147.7 ) ( 127.6 ) Purchases ( 38.2 ) ( 50.8 ) ( 20.1 ) Balance at end of year ( 236.7 ) ( 198.5 ) ( 147.7 ) Total Koppers shareholders’ equity – end of year 574.0 488.7 498.9 Noncontrolling interests Balance at beginning of year 0.3 4.1 3.6 Net income (loss) attributable to noncontrolling interests 0.0 ( 3.8 ) 0.6 Currency translation adjustment 0.0 0.0 ( 0.1 ) Balance at end of year 0.3 0.3 4.1 Total equity – end of year $ 574.3 $ 489.0 $ 503.0 The accompanying notes are an integral part of these consolidated financial statements. 45 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report KOPPERS HOLDINGS INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS 1. Description of Business Parent company of Koppers Inc. – In these financial statements, unless otherwise indicated or the context requires otherwise, when the terms Koppers, the Company, we, our or us, are used, they mean Koppers Holdings Inc. (Koppers Holdings) and its subsidiaries on a consolidated basis. The use of these terms is not intended to imply that Koppers Holdings and Koppers Inc. are not separate and distinct legal entities from each other and from their respective subsidiaries. Koppers Holdings has no direct operations and no significant assets other than the stock of Koppers Inc. It depends on the dividends from the earnings of Koppers Inc. and its subsidiaries to generate the funds necessary to meet its financial obligations. The terms of Koppers Inc.’s Credit Facility (as defined in Note 15 - Debt) prohibit Koppers Inc. from paying dividends and otherwise transferring assets except for certain limited dividends. Business description – We are a global integrated provider of treated wood products, wood treatment chemicals and carbon compounds for use in a variety of markets including the railroad, specialty chemical, utility, residential lumber, agriculture, aluminum, steel, rubber and construction industries. Our business is operated through three business segments, Railroad and Utility Products and Services (RUPS), Performance Chemicals (PC) and Carbon Materials and Chemicals (CMC). Our RUPS segment sells treated and untreated wood products, manufactured products and services primarily to the railroad industry and treated wood products to the utility industry. Railroad products and services include procuring and treating items such as crossties, switch ties and various types of lumber used for railroad bridges and crossings and the manufacture of rail joint bars. Utility products include transmission and distribution poles and pilings. The segment also operates a business related to the recovery of used crossties. We sold our railroad bridge services business during the third quarter of 2025. See Note 3 - Acquisitions and Restructuring. Our PC segment develops, manufactures, and markets wood preservation chemicals and wood treatment technologies and services a diverse range of end-markets including infrastructure, residential and commercial construction and agriculture. Our CMC segment is primarily a manufacturer of creosote, carbon pitch, naphthalene and carbon black feedstock. Creosote is used in the treatment of wood and carbon black feedstock is used in the production of carbon black. Carbon pitch is used in the production of aluminum and steel in electric arc furnaces. Naphthalene is used as a surfactant in the production of concrete. Our CMC segment ceased production of phthalic anhydride in the second quarter of 2025. See Note 3 – Acquisitions and Restructuring. 2. Summary of Significant Accounting Policies Basis of presentation – The consolidated financial statements include our accounts and all majority-owned subsidiaries for which we are deemed to exercise control over its operations. All significant intercompany transactions have been eliminated in consolidation. Certain prior period amounts in the Notes to Consolidated Financial Statements have been reclassified to conform to the current period’s presentation. Use of estimates – Accounting principles generally accepted in the United States require management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies on the date of the financial statements as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared on the basis of the most current and best available information and actual results could differ materially from these estimates. Revenue recognition – Revenue is recognized upon the completion of performance obligations under our contracts with customers and when control of a good or service is transferred to the customer. Substantially all of our contracts with customers are ship and invoice arrangements where revenue is recognized when we complete our performance obligations and transfer control to the customer. We also have certain arrangements where revenue is recognized under the contract where control of the goods or services had been transferred to the customer prior to shipment. Revenue recognition generally occurs at the point of shipment; however in certain circumstances, as shipping terms dictate, we transfer control, and revenue is recognized at the point of destination. To determine the transaction price at the time when revenue is recognized, we evaluate whether the price is subject to adjustments, such as for warranties, discounts or volume rebates, to determine the net consideration to which we expect to be entitled. Payment terms are typically within 45 days. Shipping and handling costs are included as a component of cost of sales. We recognize revenue related to the procurement of certain untreated railroad crossties upon delivery to our plant and acceptance by the customer. Service revenue, consisting primarily of wood treating services, is recognized at the time the service is provided and the performance obligation is satisfied. Payment on sales of untreated railroad crossties and wood treating services are generally due within 30 days of the invoice date. 46 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Contract Balances – The timing of revenue recognition results in both billed accounts receivable and unbilled receivables, both classified as accounts receivable, net of allowance within the consolidated balance sheet. Contract assets of $ 1.8 million and $ 7.6 million are recorded within accounts receivable, net of allowance within the consolidated balance sheet as of December 31, 2025 and 2024, respectively. Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments with an original maturity of 90 days or less. Accounts receivable – We maintain allowances for doubtful accounts for estimated losses resulting from the inability of customers to make required payments. In circumstances where we become aware of a specific customer’s inability to meet its financial obligations to Koppers, a specific reserve for bad debts is recorded against amounts due. If the financial condition of our customers were to deteriorate, resulting in an inability to make payments, additional allowances may be required. Inventories – In the United States, CMC and RUPS inventories are valued at the lower of cost, utilizing the last-in, first-out (LIFO) basis, or net realizable value. Utility and Industrial Products inventories are valued at the lower of cost, utilizing the moving average cost basis, or net realizable value. PC inventories and all other inventories outside of the United States are valued at the lower of cost, utilizing the first-in, first-out (FIFO) basis, or net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. LIFO inventories constituted approximately 51 percent and 57 percent of the FIFO inventory value at December 31, 2025 and 2024, respectively. In 2025, 2024 and 2023, we recorded inventory write-downs of $ 1.2 million, $ 0.1 million and $ 0.6 million, respectively, related to the lower of cost or net realizable value for our subsidiaries that value inventory on the FIFO basis. Property, plant and equipment – Property, plant and equipment are recorded at purchased cost and include improvements that significantly increase capacities or extend useful lives of existing plant and equipment. Depreciation expense is calculated by applying the straight-line method over estimated useful lives. Estimated useful lives for buildings generally range from ten to 20 years and depreciable lives for machinery and equipment generally range from three to 15 years. Net gains and losses related to asset disposals are recognized in earnings in the period in which the disposal occurs. Routine repairs, replacements and maintenance are expensed as incurred. We periodically evaluate whether current facts and circumstances indicate that the carrying value of depreciable long-lived assets may not be recoverable. If an asset, or logical grouping of assets, is determined to be impaired, the asset is written down to its fair value using discounted future cash flows and, if available, quoted market prices. Refer to Note 3 – Acquisitions and Restructuring for additional information. Goodwill and other intangible assets – See Note 13 - Goodwill and Intangible Assets. Deferred income taxes – Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. The effect on deferred tax assets and liabilities of a change in tax laws is recognized in earnings in the period the new laws are enacted. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets unless it is more likely than not that such assets will be realized. See Note 10 – Income Taxes. Leases – Lease arrangements are determined whether or not to be a lease at inception. Right-of-use (ROU) assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments. ROU lease liabilities are recognized based on the present value of the future minimum lease payments over the term of the lease as of the start date and may include consideration of certain adjustments including non-lease components. ROU assets are determined based on the determined ROU lease liability and may include the consideration of certain adjustments including initial direct costs, prepaid lease payments, lease incentives received, and non-lease components. The option to extend or terminate a lease is included in the determination of the ROU asset and lease liability only when it is reasonably certain that we will exercise that option. See Note 16 – Leases. Cloud-Based Software Implementation Costs – Costs incurred to implement cloud-based software arrangements are capitalized within other assets on the consolidated balance sheet. Once placed in-service, these costs are amortized using the straight-line method over the remaining term of the service contract, typically one to five years , to the same caption in the consolidated statement of operations as the related service contract. December 31, 2025 2024 (Dollars in millions) Capitalized cloud-based software implementation costs $ 10.6 $ 3.8 Accumulated amortization 1.5 0.3 Net $ 9.1 $ 3.5 47 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Asset retirement obligations – Asset retirement obligations are initially recorded at present value and are capitalized as part of the cost of the related long-lived asset when sufficient information is available to estimate present value. The capitalized costs are subsequently charged to depreciation expense over the estimated useful life of the related long-lived asset. The present value of the obligation is determined by calculating the discounted value of expected future cash flows and accretion expense is recorded each month to ultimately increase this obligation to fair value. We recognize asset retirement obligations for the removal and disposal of residues; dismantling of certain tanks required by governmental authorities; cleaning and dismantling costs for owned rail cars; cleaning costs for leased rail cars and barges; and site demolition, when required by governmental authorities or by contract. The following table describes changes to our asset retirement obligation liabilities: December 31, 2025 2024 (Dollars in millions) Asset retirement obligation at beginning of year $ 14.6 $ 15.2 Accretion expense 1.0 1.0 Revision in estimated cash flows 7.2 ( 1.2 ) Cash expenditures ( 2.2 ) ( 0.4 ) Currency translation 0.6 0.0 Balance at end of year $ 21.2 $ 14.6 The revision in estimated cash flows during the year ended December 31, 2025 was due primarily to cost increases for the removal and disposal of residues and cleaning costs for railcars in addition to an acceleration of the expected timing of these costs. Litigation and contingencies – Amounts associated with litigation and contingencies are accrued when management, after taking into consideration the facts and circumstances of each matter including any settlement offers, has determined that it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Legal costs for litigation are expensed as incurred with the exception of legal fees relating to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA), sites. Environmental liabilities – We accrue for remediation costs and penalties when the responsibility to remediate is probable and the amount of related cost is reasonably estimable. If only a range of potential liability can be estimated and no amount within the range is more probable than another, the accrual is recorded at the low end of that range. Remediation liabilities are discounted if the amount and timing of the cash disbursements are readily determinable. New Accounting Pronouncements In December 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU updates income tax disclosures by requiring annual disclosures of consistent categories and greater disaggregation of information in the rate reconciliation and income taxes paid disaggregated by jurisdiction. We adopted this ASU retrospectively for all prior periods presented in the financial statements in the fourth quarter of 2025 and added the required disclosures in Note 10 – Income Taxes. In November 2024, the FASB issued ASU No. 2024-03, Income Statement - Reporting Comprehensive Income (Topic 220): Expense Disaggregation Disclosures. This ASU requires the disaggregation of certain expenses into specific categories, such as purchases of inventory, employee compensation, depreciation and intangible asset amortization. Additionally, the amendments require disclosure of the total amount of selling expenses and an annual disclosure of the definition of selling expenses. ASU No. 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments should be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to any and all prior periods presented in the financial statements. We are currently evaluating this ASU to determine its impact on our disclosures. 3. Acquisitions and Restructuring Acquisitions Greenhill – On December 22, 2025, we completed our acquisition of the assets of the untreated utility pole procurement, manufacturing and distribution business of Greenhill Reload, LLC (Greenhill) for approximately $ 20.7 million in cash, inclusive of the inventory value at closing. We financed the acquisition with cash and available borrowings under our Credit Facility (as defined in Note 15 – Debt). The acquired business is located in Oregon. We believe the acquisition, which is included in our RUPS segment, increases our presence in western markets and expands our ability to participate 48 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report in the Douglas fir transmission pole market. Transaction costs, revenue and profit related to the acquisition were not material during the year ended December 31, 2025. We accounted for the transaction as a business combination. The following table summarizes the preliminary purchase price and estimated fair value of assets acquired as of December 22, 2025. Certain information necessary to complete the purchase price allocation is not yet available, including, but not limited to, final appraisals of assets acquired. We expect to finalize the purchase price allocation once we have received all necessary information, at which time the value of the assets acquired will be revised, if necessary. Accordingly, the consolidated financial statements include a preliminary fair value determination based on assumptions and estimates that, while considered reasonable, are subject to changes, which may be material. (Dollars in millions) Cash consideration $ 20.7 Inventories 5.7 Property, plant and equipment 0.6 Customer relationship intangible assets 2.7 Fair value of assets acquired 9.0 Goodwill $ 11.7 The customer relationship intangible assets have a useful life of 15 years and are amortized on a straight-line basis. Goodwill has been allocated to the Company's RUPS segment. The Company expects the goodwill recognized will be deductible for tax purposes. Recognized goodwill is attributable to the expected synergies and other intangible assets that do not qualify for separate recognition. Brown Wood – On April 1, 2024, we completed our acquisition of substantially all of the assets of Brown Wood Preserving Company, Inc. and certain of its affiliates (Brown Wood) for approximately $ 100 million in cash, after post-closing working capital adjustments. We financed the acquisition with cash and available borrowings under our Credit Facility. Brown Wood is a utility pole treating business with principal operating locations in Alabama and Mississippi. The business we acquired, as well as the sales function, has been operationally integrated into our existing network of utility pole plants and distribution yards. We believe the acquisition, which is included in our RUPS segment, increased our presence in existing markets and offers an attractive entry point to new geographic markets for our utility pole business. Transaction costs, revenue and profit related to the acquisition were not material for the year ended December 31, 2024. We accounted for the transaction as a business combination. Plant Closures and Restructuring – The following table summarizes restructuring activities: Year Ended December 31, 2025 2024 Cumulative Total (Dollars in millions) Phthalic Anhydride Shutdown: Severance and employee benefits $ 0.9 $ 0.1 $ 1.0 Depreciation and asset disposal costs 18.7 7.9 26.6 Plant cleaning, waste disposal and demolition costs 13.4 0.0 13.4 Workforce reduction program 3.3 5.0 8.3 Consulting services 15.6 0.3 15.9 Other plant restructuring costs 0.0 3.6 3.6 Total impairment and restructuring $ 51.9 $ 16.9 $ 68.8 Phthalic Anhydride Shutdown – In December 2024, we made the decision to discontinue phthalic anhydride production at our facility in Stickney, Illinois. The decision was driven by significant near-term capital spending requirements that could not be economically justified by end-market projections and will substantially reduce annual emissions of certain regulated air contaminants. During the second quarter of 2025, we completed the shutdown of the phthalic anhydride plant. We expect this action to result in pre-tax charges to earnings of $ 50 million to $ 54 million through the end of 2026, approximately $ 28 million of which constitutes non-cash charges and approximately $ 22 million to $ 26 million of which constitutes cash expenditures. Estimates of the total cumulative pre-tax amount incurred and to be incurred for each major type of cost associated with the discontinuation plan are: (i) retention and severance costs of approximately $ 1 million, (ii) accelerated depreciation and asset write-down costs of approximately $ 28 million, and (iii) plant cleaning, waste disposal and demolition costs of approximately $ 21 million to $ 25 million. 49 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Workforce Reduction Program – In November 2024, we committed to a workforce reduction program across select U.S. locations, which was intended to streamline operations and reduce costs. This workforce reduction program resulted in the reallocation of people and resources, included voluntary and involuntary reductions in employees and ended in the fourth quarter of 2025. Consulting Services – We have incurred and will continue to incur consulting and other professional service fees starting with a comprehensive assessment of each of our businesses and functions which began in the fourth quarter of 2024 and was completed during the third quarter of 2025. We then started the multi-year company-wide transformative project to design and implement changes that we believe will enable us to reach our full potential and improve profitability, modernize business processes and pursue portfolio realignment, if necessary. The following table includes details of plant closures and restructuring liabilities: Phthalic Anhydride Shutdown Workforce Reduction Program (Dollars in millions) Liability at December 31, 2024 $ 0.0 $ 4.4 Accrual 13.5 1.2 Cash paid ( 8.1 ) ( 5.0 ) Liability at December 31, 2025 $ 5.4 $ 0.6 KRS Sale – On August 29, 2025, we sold our railroad bridge services business, Koppers Railroad Structures Inc., which was previously included in our RUPS segment. KCCC Liquidation – In July 2024, Koppers and Tangshan Iron & Steel Group Co. Ltd. (TISCO) signed an agreement to effectuate the ultimate liquidation of Koppers (China) Carbon & Chemical Company Limited (KCCC), which ceased operations in 2015. KCCC is owned 60 percent by a wholly owned subsidiary of Koppers and 40 percent by TISCO. As a result of the signed agreement in 2024, we recorded a loss on sale of $ 5.9 million, net of non-controlling interest. During the first quarter of 2025, TISCO assumed the remaining assets, including land, and liabilities of KCCC, which resulted in cash paid of approximately $ 7.6 million. The liquidation of KCCC was completed in February 2026. In March 2023, we sold certain assets from KCCC and recorded a gain on sale of $ 1.8 million. 4. Common Stock and Senior Convertible Preferred Stock There was no senior convertible preferred stock issued or outstanding for the periods presented. The following table presents the changes in common stock and treasury stock: December 31, 2025 2024 2023 (Shares in thousands) Common Stock Issued: Balance at beginning of year 25,761 25,163 24,547 Issued for employee stock plans 452 598 616 Balance at end of year 26,213 25,761 25,163 Treasury Stock: Balance at beginning of year ( 5,480 ) ( 4,303 ) ( 3,784 ) Shares repurchased ( 1,277 ) ( 1,177 ) ( 519 ) Balance at end of year ( 6,757 ) ( 5,480 ) ( 4,303 ) Common Stock Outstanding 19,456 20,281 20,860 5. Derivative Financial Instruments We utilize derivative instruments to manage exposures to risks that have been identified, measured and are capable of being mitigated. The primary risks that we manage by using derivative instruments are commodity price risk associated with copper, fuel oil, foreign currency exchange risk, principally the U.S. dollar and British pound sterling, and interest rate risk associated with variable rate borrowings. Generally, we enter into master netting arrangements with the counterparties and offset net derivative positions with the same counterparties. Currently, our agreements do not require cash collateral. The Company recognizes all derivative instruments as either assets or liabilities at fair value on the balance sheet. The derivative instruments are classified as current or noncurrent based upon the expected timing of cash flows and are subject to offset under our master netting arrangements. A derivative instrument's fair value is determined using significant other observable inputs, a Level 2 fair value measurement. 50 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive income and is reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative instruments representing hedge ineffectiveness are recognized in current earnings. In our consolidated statement of cash flows, settlements of derivative instruments are classified as operating activities. Swap contracts on copper are used to manage the price risk associated with forecasted purchases of materials used in our manufacturing processes. Generally, we will not hedge cash flow exposures for durations longer than 36 months and we have hedged certain volumes of copper through the end of 2026. We designate certain of our commodity swaps as cash flow hedges of forecasted purchases of commodities. For those commodity swaps where hedge accounting is not elected, the unrealized gain or loss on the derivative is reported as cost of sales in the consolidated statement of operations. We enter into heating oil swap contracts to manage price risk associated with fuel oil purchases for our plant operations and certain raw material requirements. Generally, we will not hedge cash flow exposures for durations longer than 36 months and we have hedged certain volumes of heating oil through the end of 2027. These swap contracts are not designated as hedges so the unrealized gain or loss on the derivative is reported as cost of sales in the consolidated statement of operations. As of December 31, 2025 and 2024, we had contracts totaling 3.8 million and 3.5 million gallons, respectively. We enter into foreign currency forward contracts to manage foreign currency risk associated with our receivable and payable balances in addition to foreign-denominated sales. These forward contracts related to foreign currency are not designated as hedges so the unrealized gain or loss on the derivative is reported as cost of sales in the consolidated statement of operations. We enter into interest rate swaps to effectively convert portions of our variable interest rate debt into fixed rate debt to add stability to interest expense and to manage our exposure to interest rate movements. We entered into interest rate swap agreements with an aggregate notional value of $ 400.0 million at a weighted average fixed Secured Overnight Financing Rate (SOFR) of 3.97 percent for a portion of our variable rate debt. All swap agreements expire in April 2027. The interest rate swaps have been designated as cash flow hedges on interest payments involving the receipt of variable amounts from a counterparty in exchange for us making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. See the consolidated statement of comprehensive income and consolidated statement of shareholders’ equity for amounts recorded in other comprehensive income and for amounts reclassified from accumulated other comprehensive income into net income for each of the three years ended December 31, 2025. The fair value of the outstanding derivative contracts recorded in the balance sheet are as follows: December 31, 2025 Copper Swap Contracts Heating Oil Contracts Foreign Currency Forward Contracts Interest Rate Swap Contracts Total (Dollars in millions) Derivative contracts $ 31.4 $ 0.0 $ 0.0 $ 0.1 $ 31.5 Accrued liabilities 0.0 ( 0.4 ) 0.0 ( 2.2 ) ( 2.6 ) Other long-term liabilities 0.0 0.0 0.0 ( 1.1 ) ( 1.1 ) Net asset (liability) on balance sheet $ 31.4 $ ( 0.4 ) $ 0.0 $ ( 3.2 ) $ 27.8 Accumulated other comprehensive gain (loss), net of tax $ 2.5 $ 0.0 $ 0.0 $ ( 2.4 ) $ 0.1 51 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report December 31, 2024 Copper Swap Contracts Heating Oil Contracts Foreign Currency Forward Contracts Interest Rate Swap Contracts Total (Dollars in millions) Derivative contracts $ 0.3 $ 0.0 $ 0.0 $ 1.2 $ 1.5 Other assets 0.0 0.0 0.0 1.0 1.0 Accrued liabilities ( 7.6 ) ( 0.5 ) ( 0.9 ) ( 0.5 ) ( 9.5 ) Other long-term liabilities ( 1.6 ) 0.0 0.0 ( 1.3 ) ( 2.9 ) Net (liability) asset on balance sheet $ ( 8.9 ) $ ( 0.5 ) $ ( 0.9 ) $ 0.4 $ ( 9.9 ) Accumulated other comprehensive loss, net of tax $ ( 2.0 ) $ 0.0 $ 0.0 $ ( 0.3 ) $ ( 2.3 ) We estimate that unrealized gains, net of tax, for commodity price hedging of $ 2.1 million and unrealized losses, net of tax, for interest rate swaps of $ 1.6 million, respectively, will be reclassified from accumulated other comprehensive income into earnings over the next twelve months . During the third quarter of 2025, our quarterly effectiveness assessment identified that our hedging contracts had fallen outside the required effectiveness thresholds to continue cash flow hedge accounting. This was caused by the increased and cumulative volatility in the market prices for copper during the first half of 2025. Accordingly, we prospectively discontinued cash flow hedge accounting in the third quarter of 2025. At the time we discontinued cash flow hedge accounting, accumulated other comprehensive income contained a pre-tax gain of $ 5.8 million ($ 4.4 million net of taxes). This amount will be released to income as the underlying hedge contracts mature through December 2026. As a result of discontinuing cash flow hedge accounting, a net cumulative pre-tax unrealized gain of $ 15.0 million was recorded in earnings during the year ended December 31, 2025. Subsequent changes in the fair value of these copper swap contracts will continue to be recognized immediately in earnings until such swap contracts settle or mature. The unrealized gain (loss) from our hedging contracts is as follows: Year Ended December 31, 2025 2024 2023 (Dollars in millions) Copper swap contracts $ 19.1 $ ( 7.7 ) $ 0.9 Heating oil contracts 0.1 ( 0.2 ) 0.0 Foreign currency forward contracts 0.3 ( 0.2 ) 0.0 Copper Swap Contracts We had outstanding copper swap contracts of the following amounts: Units Outstanding (in Pounds) Net Fair Value - Asset (Liability) December 31, December 31, 2025 2024 2025 2024 (Amounts in millions) Cash flow hedges 0.0 20.7 $ 0.0 $ ( 2.7 ) Not designated as hedges 25.6 26.7 31.4 ( 6.2 ) Total 25.6 47.4 $ 31.4 $ ( 8.9 ) Foreign Currency Forward Contracts The net currency units outstanding for contracts were: December 31, 2025 2024 (In millions) British Pound Sterling GBP 0.3 GBP 0.5 United States Dollars USD 9.2 USD 18.5 52 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report 6. Fair Value Measurements The following table presents the estimated fair values and the related carrying amounts of our financial instruments: December 31, 2025 December 31, 2024 Fair Value Carrying Value Fair Value Carrying Value (Dollars in millions) Assets - Investments and other assets $ 1.3 $ 1.3 $ 1.4 $ 1.4 Liabilities - Debt (including current portion) $ 933.6 $ 928.3 $ 949.1 $ 939.5 Investments and other assets – Represents the broker-quoted cash surrender value on universal life insurance policies. This asset is classified as Level 2 in the valuation hierarchy and is measured from values received from financial institutions. Debt – The fair value of our long-term debt is estimated based on the market prices for the same or similar issuances or on the current rates offered to us for debt of the same remaining maturities (Level 2). The fair value of our Credit Facility approximates carrying value due to the variable rate nature of this instrument. See Note 5 – Derivative Financial Instruments, for the fair value of our derivative financial instruments. 7. Earnings and Dividends per Common Share The computation of basic earnings per common share for the periods presented is based upon the weighted average number of common shares outstanding during the periods. The computation of diluted earnings per common share under the treasury stock method includes the effect of non-vested nonqualified stock options and stock units assuming such options and stock units were outstanding common shares at the beginning of the period. The effect of antidilutive securities is excluded from the computation of diluted loss per common share, if any. The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31, 2025 2024 2023 (Dollars in millions, except share amounts, in thousands, and per share amounts) Net income attributable to Koppers $ 56.0 $ 52.4 $ 89.2 Weighted average common shares outstanding: Basic 19,855 20,659 20,835 Effect of dilutive securities 550 632 704 Diluted 20,405 21,291 21,539 Earnings per common share: Basic $ 2.82 $ 2.54 $ 4.28 Diluted 2.74 2.46 4.14 Antidilutive securities excluded from computation of diluted earnings per common share 467 108 315 On February 11, 2026, the board of directors declared a quarterly dividend of $ 0.09 per common share, payable on March 23, 2026 to shareholders of record as of March 6, 2026. 8. Stock-based Compensation We have outstanding stock-based compensation awards that were granted under the amended and restated 2005 Long-Term Incentive Plan (the 2005 LTIP), the 2018 Long-Term Incentive Plan (the 2018 LTIP) and the 2020 Long-Term Incentive Plan, as amended (the 2020 LTIP). The 2005 LTIP, the 2018 LTIP and the 2020 LTIP are collectively referred to as the LTIP. The LTIP provides for the grant to eligible persons of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance awards, dividend equivalents and other stock-based awards, which are collectively referred to as the awards. Restricted Stock Units and Performance Stock Units Under the LTIP, the board of directors grants restricted stock units and performance stock units to certain employee participants (collectively, the stock units). Compensation expense for non-vested stock units is recorded over the vesting period based on the fair value at the date of grant. The fair value of restricted stock units is the market price of the underlying common stock on the date of grant. The fair value of performance stock units is determined using the market price of the underlying common stock on the date of grant for units with a performance condition and a Monte Carlo valuation model for units with a market condition. 53 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report For grants to most employees prior to 2023 and after 2024, the restricted stock units vest in four equal annual installments. In 2023 and 2024, most grants of restricted stock units vest in three years . Restricted stock units that have one-year vesting periods are also issued under the LTIP to members of the board of directors in connection with annual director compensation and, from time to time, are issued to employees with vesting periods of typically two years or less. Performance stock units have vesting based upon either a performance condition or a market condition. Performance stock units granted with a performance condition have a cumulative three-year performance objective based on adjusted EBITDA (see Note 9 – Segment Information). For performance stock units granted with a market condition, which applies to all performance stock unit grants made prior to 2023, the applicable objective is based on our total shareholder return relative to the Standard & Poor’s SmallCap 600 Materials Index and has multi-year performance objectives. Both types of performance stock units have a three-year period for vesting. The number of performance stock units granted represents the target award, and participants have the ability to earn between zero and 200 percent of the target award based upon actual performance. If minimum performance criteria are not achieved, no performance stock units will vest. We have the discretion to settle the award in cash rather than shares, although we currently expect that all awards will be settled by the issuance of shares. We calculated the fair value of the performance stock unit awards with a market condition on the date of the grant using assumptions listed below: January 2025 January 2024 January 2023 Grant date price per share of stock performance award $ 31.72 $ 46.68 $ 29.01 Expected volatility 38.02 % 38.14 % 66.30 % Risk-free interest rate 4.32 % 4.14 % 4.11 % Look-back period in years 3.00 3.00 3.00 Fair value cap per share $ 65.00 N/A N/A Grant date fair value per share $ 34.54 $ 59.41 $ 39.51 Dividends declared, if any, on our common stock during the period prior to vesting of the stock units are credited at equivalent value as additional stock units and become payable as additional common shares upon vesting. In the event of termination of employment, other than retirement, death or disability, any non-vested stock units are forfeited, including additional stock units credited from dividends. In the event of termination of employment due to retirement, death or disability, pro-rata vesting of the stock units over the service period will result for awards prior to 2024. Starting in 2024, if certain conditions are met, continued vesting will result. There are special vesting provisions for the stock units related to a change in control. The following table shows a summary of the performance stock units as of December 31, 2025: Performance Period Minimum Shares Target Shares Maximum Shares Market Condition Units: 2023 – 2025 119,519 119,519 119,519 2024 – 2026 0 38,500 77,000 2025 – 2027 0 224,439 448,878 Performance Condition Units: 2023 – 2025 210,405 210,405 210,405 2024 – 2026 0 122,864 245,728 2025 – 2027 0 112,859 225,718 The minimum, target and maximum shares above reflect the impact from completed performance periods. Performance stock units with a market condition granted in January 2023 for the 2023 - 2025 performance period vested in January 2026 at 150.0 percent of the original target share amount plus dividend equivalent units. Performance stock units with a performance condition granted in January 2023 for the 2023 – 2025 performance period vested in January 2026 at 116.1 percent of the original target share amount plus dividend equivalent units. The above awards include 137,226 target shares for performance stock units with a market condition and 31,167 restricted stock units that were issued in lieu of a portion of the cash incentive award that could be earned during 2025 for certain participants. These stock units vest over a three-year period. Combined with other changes to the cash incentive award program, including the change in which certain participants had a portion of their annual award converted into a three-year stock unit award to promote retention, we expect to save approximately $ 5 million in expenses for 2025 with such amount being recognized over the subsequent two years . 54 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report The following table shows a summary of the status and activity of non-vested stock awards: Restricted Stock Units Performance Stock Units Total Stock Units Weighted Average Grant Date Fair Value per Unit Non-vested at December 31, 2024 432,040 624,388 1,056,428 $ 39.16 Granted 347,990 335,563 683,553 $ 32.26 Credited from dividends 5,169 8,360 13,529 $ 36.09 Performance share adjustment 0 ( 62,241 ) ( 62,241 ) $ 41.99 Vested ( 242,618 ) ( 159,087 ) ( 401,705 ) $ 39.57 Forfeited ( 12,344 ) ( 12,752 ) ( 25,096 ) $ 34.57 Non-vested at December 31, 2025 530,237 734,231 1,264,468 $ 35.22 Stock Options Stock options to most executive officers vest and become exercisable in four equal annual installments. The stock options have a term of ten years . In the event of termination of employment, other than retirement, death or disability, any non-vested options are forfeited. In the event of termination of employment due to retirement, death or disability, pro-rata vesting of the options over the service period will result. There are special vesting provisions for the stock options related to a change in control. No stock options were granted subsequent to 2022. Compensation expense for non-vested stock options is recorded over the vesting period based on the fair value at the date of grant. The following table shows a summary of the status and activity of stock options: Options Weighted Average Exercise Price per Option Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in millions) Outstanding at December 31, 2024 531,532 $ 28.49 Exercised ( 16,599 ) $ 17.91 Expired ( 7,803 ) $ 42.75 Outstanding at December 31, 2025 507,130 $ 28.62 3.45 $ 1.4 Exercisable at December 31, 2025 484,091 $ 28.45 3.33 $ 1.4 Stock Compensation Expense The following table presents total stock-based compensation expense recognized under our LTIP and employee stock purchase plan in the consolidated statement of operations: Year Ended December 31, 2025 2024 2023 (Dollars in millions) Selling, general and administrative expenses $ 13.8 $ 20.8 $ 17.3 Less related income tax benefit 4.3 6.2 4.8 Decrease in net income attributable to Koppers $ 9.5 $ 14.6 $ 12.5 Intrinsic value of exercised stock options $ 0.2 $ 4.5 $ 6.4 Cash received from the exercise of stock options $ 0.2 $ 3.9 $ 8.8 As of December 31, 2025, total future compensation expense related to non-vested stock-based compensation arrangements totaled $ 14.5 million and the weighted-average period over which this expense is expected to be recognized is approximately 24.9 months. 9. Segment Information See Note 1 - Description of Business for a discussion of our three reportable segments. Our reportable segments contain multiple aggregated business units since management believes the long-term financial performance of these business units is affected by similar economic conditions. The reportable segments are each managed separately because they manufacture and distribute distinct products with different production processes. Our measure of segment profitability is adjusted income before interest expense, income taxes, depreciation, amortization and certain non-cash and/or non-recurring items that do not contribute directly to management’s evaluation of our operating results (as defined by us, adjusted EBITDA). These non-cash and/or non-recurring items typically include LIFO inventory effects, impairment, restructuring and plant closure costs, significant gains or losses on sale of assets, mark-to- 55 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report market commodity hedging, acquisition-related charges, amortization of cloud-based software implementation costs and other unusual items. The Chief Operating Decision Maker (CODM) is Koppers' Chief Executive Officer, Leroy M. Ball. This presentation is consistent with how our CODM evaluates the results of operations and makes strategic decisions about the business. The segments regularly provide the reported measures below to the CODM for historical, current and forecasted periods. Together, this allows the CODM to assess segment performance and decide how to allocate resources between segments. In addition, adjusted EBITDA is the primary measure used to determine the level of achievement of management’s short-term incentive goals and related payout, as well as one of the measures used to determine performance and related payouts for certain performance share units granted to management. For these reasons, we believe that adjusted EBITDA represents the most relevant measure of segment profit and loss. Adjusted EBITDA is reconciled to net income on a consolidated basis, the most directly comparable financial measure determined and reported in accordance with U.S. generally accepted accounting principles (U.S. GAAP). The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies. Intersegment transactions are eliminated in consolidation. Segment Revenues for Significant Product Lines Year Ended December 31, 2025 2024 2023 (Dollars in millions) Railroad and Utility Products and Services: Railroad treated products $ 551.5 $ 564.3 $ 540.9 Utility poles 304.6 289.4 266.1 Railroad infrastructure products and services 70.7 89.0 90.9 Total Railroad and Utility Products and Services $ 926.8 $ 942.7 $ 897.9 Performance Chemicals: Wood preservative and other products $ 543.8 $ 651.6 $ 671.6 Carbon Materials and Chemicals: Pitch and related products $ 299.6 $ 294.8 $ 394.4 Phthalic anhydride, naphthalene and other chemicals 51.6 122.8 112.0 Carbon black feedstock and distillates 57.5 80.2 78.3 Total Carbon Materials and Chemicals $ 408.7 $ 497.8 $ 584.7 Total $ 1,879.3 $ 2,092.1 $ 2,154.2 56 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Segment Expenses Year Ended December 31, 2025 2024 2023 (Dollars in millions) Cost of sales: Railroad and Utility Products and Services $ 749.6 $ 800.1 $ 753.9 Performance Chemicals 356.2 454.8 485.0 Carbon Materials and Chemicals 325.7 414.6 490.8 Total $ 1,431.5 $ 1,669.5 $ 1,729.7 Selling, general and administrative expenses: Railroad and Utility Products and Services $ 65.2 $ 75.4 $ 62.9 Performance Chemicals 60.2 65.2 65.7 Carbon Materials and Chemicals 29.5 38.7 45.5 Total $ 154.9 $ 179.3 $ 174.1 Other expense (income) to reconcile to Adjusted EBITDA (1) : Railroad and Utility Products and Services $ 3.9 $ ( 15.1 ) $ ( 2.9 ) Performance Chemicals 24.7 ( 11.1 ) ( 2.2 ) Carbon Materials and Chemicals 7.6 7.9 ( 0.9 ) Total $ 36.2 $ ( 18.3 ) $ ( 6.0 ) Adjusted EBITDA: Railroad and Utility Products and Services $ 108.1 $ 82.3 $ 84.0 Performance Chemicals 102.7 142.7 123.1 Carbon Materials and Chemicals 45.9 36.6 49.3 Total $ 256.7 $ 261.6 $ 256.4 (1) Other expense (income) amounts primarily relate to miscellaneous (income) expense and the adjustments to reconcile to adjusted EBITDA such as acquisition-related charges, mark-to-market commodity hedging and LIFO inventory effects. Segment Adjusted EBITDA Year Ended December 31, 2025 2024 2023 (Dollars in millions) Adjusted EBITDA: Railroad and Utility Products and Services $ 108.1 $ 82.3 $ 84.0 Performance Chemicals 102.7 142.7 123.1 Carbon Materials and Chemicals 45.9 36.6 49.3 Items excluded from the determination of segment profit: LIFO benefit (expense) (1) 11.0 ( 6.1 ) ( 6.0 ) Impairment, restructuring and plant closure costs (2) ( 51.9 ) ( 17.3 ) ( 0.1 ) Gain (loss) on sale of assets 0.4 ( 10.7 ) 1.8 Mark-to-market commodity hedging gains (losses) 34.2 ( 7.9 ) 0.5 Acquisition inventory step-up amortization 0.0 ( 2.3 ) 0.0 Amortization of cloud-based software implementation costs ( 1.2 ) ( 0.3 ) 0.0 Pension settlement and expense ( 28.3 ) ( 4.0 ) 0.0 Interest expense ( 66.1 ) ( 76.2 ) ( 71.0 ) Depreciation and amortization ( 73.6 ) ( 67.5 ) ( 57.0 ) Income tax expense ( 25.2 ) ( 20.7 ) ( 34.8 ) Net income $ 56.0 $ 48.6 $ 89.8 (1) The LIFO expense adjustment removes the entire impact of LIFO and effectively reflects the results as if we were on a FIFO inventory basis. (2) See Note 3 - Acquisitions and Restructuring. 57 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Other Segment Disclosures Year Ended December 31, 2025 2024 2023 (Dollars in millions) Intersegment revenues: Performance Chemicals $ 31.3 $ 31.7 $ 28.9 Carbon Materials and Chemicals 90.7 93.7 87.4 Total $ 122.0 $ 125.4 $ 116.3 Depreciation and amortization expense: Railroad and Utility Products and Services $ 33.5 $ 32.1 $ 24.6 Performance Chemicals 16.1 15.1 13.9 Carbon Materials and Chemicals 24.0 20.3 18.5 Total $ 73.6 $ 67.5 $ 57.0 Capital expenditures: Railroad and Utility Products and Services $ 19.2 $ 32.1 $ 49.8 Performance Chemicals 15.2 15.2 15.1 Carbon Materials and Chemicals 18.9 27.5 50.7 Corporate 1.7 2.6 4.9 Total $ 55.0 $ 77.4 $ 120.5 Segment Assets December 31, 2025 2024 (Dollars in millions) Segment assets: Railroad and Utility Products and Services $ 827.5 $ 839.2 Performance Chemicals 536.6 499.7 Carbon Materials and Chemicals 486.7 506.3 Corporate 36.0 45.0 Total $ 1,886.8 $ 1,890.2 Goodwill: Railroad and Utility Products and Services $ 156.4 $ 145.6 Performance Chemicals 173.0 171.5 Total $ 329.4 $ 317.1 58 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Revenues and Long-lived Assets by Geographic Area 2025 2024 2023 (Dollars in millions) United States Revenue $ 1,280.9 $ 1,475.6 $ 1,468.1 Long-lived assets 1,016.7 1,021.2 942.3 Australasia Revenue 249.0 247.0 265.0 Long-lived assets 77.8 76.3 75.6 Europe Revenue 171.5 181.6 213.3 Long-lived assets 100.8 88.8 91.0 Other countries Revenue 177.9 187.9 207.8 Long-lived assets 15.8 14.9 17.2 Total Revenue $ 1,879.3 $ 2,092.1 $ 2,154.2 Long-lived assets $ 1,211.1 $ 1,201.2 $ 1,126.1 Revenue from non-US countries $ 598.4 $ 616.5 $ 686.1 Revenues by geographic area in the above table are attributed by the destination country of the sale. 59 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report 10. Income Taxes Income Tax Provision Components of our income tax provision are as follows: Year Ended December 31, 2025 2024 2023 (Dollars in millions) Income before income taxes: US $ 22.0 $ 21.2 $ 47.8 Foreign 59.2 48.1 76.8 Total income before income taxes $ 81.2 $ 69.3 $ 124.6 Current: US Federal $ 1.1 $ 1.9 $ 7.3 US State and Local 0.2 0.6 1.7 Foreign 12.6 15.4 20.1 Total current tax provision $ 13.9 $ 17.9 $ 29.1 Deferred: US Federal $ 5.5 $ 1.8 $ 3.1 US State and Local 2.0 0.2 0.6 Foreign 3.8 0.8 2.0 Total deferred tax provision $ 11.3 $ 2.8 $ 5.7 Total income tax provision: US Federal $ 6.6 $ 3.7 $ 10.4 US State and Local 2.2 0.8 2.3 Foreign 16.4 16.2 22.1 Total income tax provision $ 25.2 $ 20.7 $ 34.8 Components of our cash paid for income taxes are as follows: Year Ended December 31, 2025 2024 2023 (Dollars in millions) Domestic: US Federal $ ( 4.6 ) $ 7.9 $ 3.2 US State and Local 0.8 1.3 1.4 Total domestic $ ( 3.8 ) $ 9.2 $ 4.6 Foreign: Australia $ 9.3 $ 9.7 $ 15.9 Netherlands (1) 0.0 2.2 8.0 Canada (1) 1.6 1.9 0.0 Brazil 0.8 1.9 2.4 Chile (1) 0.9 0.0 0.0 Other 0.6 2.7 3.4 Total foreign $ 13.2 $ 18.4 $ 29.7 Total cash paid for income taxes $ 9.4 $ 27.6 $ 34.3 (1) The amount of income taxes paid during certain years does not meet the five percent disaggregation threshold; therefore, the amount is not disclosed. 60 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report The provision for income taxes is reconciled with the federal statutory income tax rate as follows: Year Ended December 31, 2025 2024 2023 Amount Percent Amount Percent Amount Percent (Dollars in millions) Domestic federal income tax $ 17.1 21.0 % $ 14.6 21.0 % $ 26.2 21.0 % Tax credits ( 0.6 ) ( 0.7 ) ( 0.6 ) ( 0.9 ) ( 0.2 ) ( 0.2 ) Nontaxable and nondeductible items: Section 162(m) adjustment 1.1 1.4 1.6 2.3 1.6 1.3 Excess tax benefits on stock-based payments 0.3 0.4 ( 1.1 ) ( 1.6 ) ( 0.6 ) ( 0.5 ) Other 0.4 0.5 0.6 0.9 0.6 0.5 Cross-border tax laws Global intangible low-taxed income 1.2 1.5 ( 0.1 ) ( 0.2 ) ( 1.4 ) ( 1.1 ) Other 0.0 0.0 ( 0.2 ) ( 0.3 ) ( 0.2 ) ( 0.2 ) Other ( 0.4 ) ( 0.5 ) ( 0.1 ) ( 0.1 ) 0.6 0.5 State and local, net of federal 1.7 2.1 0.7 1.0 1.7 1.4 Foreign tax effects Australia statutory income tax rate difference 2.7 3.3 2.6 3.8 4.5 3.6 Australia other 0.2 0.2 0.0 0.0 ( 0.1 ) ( 0.1 ) Netherlands fiscal unity 0.2 0.2 0.8 1.2 0.2 0.2 China change in valuation allowance 0.0 0.0 2.6 3.8 0.0 0.0 China other 0.0 0.0 ( 0.4 ) ( 0.6 ) ( 0.1 ) ( 0.1 ) New Zealand deferred tax liability adjustment 0.0 0.0 ( 1.0 ) ( 1.4 ) 0.0 0.0 New Zealand other 0.0 0.0 ( 0.2 ) ( 0.3 ) 0.0 0.0 Other foreign jurisdictions 1.3 1.6 1.6 2.3 1.7 1.4 Change in unrecognized tax benefits 0.0 0.0 ( 0.7 ) ( 1.0 ) 0.3 0.2 Annual effective income tax $ 25.2 31.0 % $ 20.7 29.9 % $ 34.8 27.9 % In 2025, state and local income taxes in Georgia, Illinois, Kentucky, North Carolina, Virginia and Texas comprise the majority of the domestic state and local income taxes, net of federal effect. In 2024, state and local income taxes in South Carolina and Texas comprise the majority of the domestic state and local income taxes, net of federal effect. In 2023, state and local income taxes in Georgia, Pennsylvania, South Carolina and Texas comprise the majority of the domestic state and local income taxes, net of federal effect. On July 4, 2025, H.R. 1, the U.S. budget reconciliation bill, was signed into law. We have analyzed the various components of the bill and incorporated the effects into our US tax provision. We have determined that the financial statement impact of the budget reconciliation bill is not material and the effect on our effective income tax rate is not material. The primary impact of the budget reconciliation bill is an increase of our current year interest expense deduction under Section 163(j). Effective January 1, 2024, certain jurisdictions in which we operate have enacted legislation that is consistent with one or more Organization for Economic Co-operation and Development Global Anti-Base Erosion Model Rules (commonly referred to as "Pillar Two"). These Pillar Two rules include minimum domestic top up taxes, income inclusion rules and undertaxed profit rules all aimed to ensure that multinationals pay a minimum effective corporate tax rate of 15 percent in each jurisdiction in which they operate. We have analyzed our tax profile by jurisdiction and have determined that we are not subject to top up taxes in 2025. Taxes Excluded from Net Income Attributable to Koppers The amount of deferred income tax benefit (expense) included in comprehensive income but excluded from net income attributable to Koppers relates primarily to adjustments to copper and interest rate swap contracts of $( 1.1 ) million, $ 0.5 million and $ 0.8 million for the years ended December 31, 2025, 2024 and 2023, respectively. The amount of deferred income tax benefit (expense) included in comprehensive income but excluded from net income attributable to Koppers relates to adjustments to reflect the unfunded status of employee post-retirement benefit plans of $( 7.8 ) million, $( 0.3 ) million and $ 1.1 million for the years ended December 31, 2025, 2024 and 2023, respectively. 61 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Deferred Tax Assets and Liabilities Deferred income taxes reflect the net tax effects of differences between the carrying amounts of assets and liabilities for financial reporting purposes and for income tax purposes. Significant components of our deferred tax assets and liabilities are as follows: Year Ended December 31, 2025 2024 (Dollars in millions) Deferred tax assets: Federal and state tax loss carryforwards, expiring in 2026 to 2045 $ 27.7 $ 20.8 Interest disallowance 14.3 15.4 Tax credits 12.1 17.3 Foreign tax loss carryforwards 11.3 8.1 Reserves, including insurance and environmental 9.3 11.8 Inventory 8.0 8.6 Asset retirement obligations 6.7 4.8 Accrued employee compensation 5.7 8.2 Pension and other post-retirement benefits obligations 3.6 3.9 Other 10.1 11.3 Valuation allowance ( 42.0 ) ( 46.6 ) Total deferred tax assets 66.8 63.6 Deferred tax liabilities: Tax over book depreciation and amortization 97.0 83.1 Gain (loss) on derivative contracts 6.5 ( 2.0 ) Total deferred tax liabilities 103.5 81.1 Net deferred tax liabilities $ ( 36.7 ) $ ( 17.5 ) As a result of the Tax Cuts and Jobs Act of 2017 (the Tax Act) and the one-time mandatory transition tax, all previously unremitted earnings for which a U.S. deferred tax liability had not been accrued have now been subject to U.S. tax. As of December 31, 2025, there was approximately $ 591 million of such unremitted earnings. Substantially all unremitted earnings will remain indefinitely invested in our foreign subsidiaries for the foreseeable future unless we can remit any earnings as a dividend in a tax-free manner. In the event any earnings are remitted as a dividend with a tax cost due to currency gains or losses, state taxes, or foreign withholding taxes, we estimate that we will not incur significant additional taxes on those potential remittances. Management evaluated the ability to realize the deferred tax assets that are related to our domestic and international operations. In assessing the need for a valuation allowance, management considered all positive and negative evidence related to the realization of our net deferred tax assets. We believe that we will be in a taxable income position in the foreseeable future and we will have sufficient taxable income to utilize deferred tax assets that do not have a valuation allowance related to our domestic and international operations. A valuation allowance is necessary when it is more likely than not that a deferred tax asset will not be realized. Certain deferred tax assets reflected above are not expected to be realized, and a valuation allowance has been provided for them. Valuation allowances are recorded to offset the following deferred tax assets: December 31, 2025 2024 (Dollars in millions) State temporary differences, net operating losses and tax credits $ 20.4 $ 20.4 Federal foreign tax credits 10.8 15.8 Foreign temporary differences, net operating losses and capital losses 10.8 10.4 Total valuation allowances $ 42.0 $ 46.6 62 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Unrecognized Tax Benefits A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: December 31, 2025 2024 2023 (Dollars in millions) Balance at beginning of year $ 1.0 $ 1.5 $ 1.4 Additions based on tax provisions related to the current year 0.3 0.2 0.3 Reductions resulting from a lapse in the statute of limitations ( 0.2 ) ( 0.7 ) ( 0.2 ) Balance at end of year $ 1.1 $ 1.0 $ 1.5 As of December 31, 2025 and 2024, the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate, was approximately $ 1.1 million and $ 1.0 million, respectively. We do not anticipate significant increases or decreases to the amount of unrecognized tax benefits within the next twelve months. We recognize interest expense and any related penalties from unrecognized tax benefits in income tax expense. For the year ended December 31, 2025, we recognized less than $ 0.1 million in interest and penalties. As of December 31, 2025 and 2024, we had accrued interest and penalties of approximately $ 0.2 million for each year. Koppers Holdings and its subsidiaries file income tax returns in the U.S. federal jurisdiction, individual U.S. state jurisdictions and non-U.S. jurisdictions. With few exceptions, we are no longer subject to U.S. federal, U.S. state, or non-U.S. income tax examinations by tax authorities for years before 2020. 11. Inventories December 31, 2025 2024 (Dollars in millions) Raw materials $ 351.6 $ 353.5 Work in process 17.3 14.0 Finished goods 147.0 152.8 Total 515.9 520.3 Less revaluation to LIFO 104.7 115.7 Inventories, net $ 411.2 $ 404.6 12. Property, Plant and Equipment December 31, 2025 2024 (Dollars in millions) Land $ 16.3 $ 17.3 Buildings 122.6 112.5 Machinery and equipment 977.4 1,025.4 Total 1,116.3 1,155.2 Less accumulated depreciation 465.4 494.4 Property, plant and equipment, net $ 650.9 $ 660.8 Depreciation expense for the years ended December 31, 2025, 2024 and 2023 amounted to $ 57.6 million, $ 51.7 million and $ 42.5 million, respectively. In addition, we recognized accelerated depreciation expense of $ 19.7 million and $ 4.4 million in restructuring charges in the consolidated statement of operations for the years ended December 31, 2025 and 2024, respectively. See Note 3 – Acquisitions and Restructuring. Impairments – We did not incur impairment charges in 2025, 2024 and 2023. 13. Goodwill and Intangible Assets Goodwill and other purchased intangible assets are included in the identifiable assets of the business segment to which they have been assigned. Goodwill is assessed for impairment annually, using a quantitative goodwill impairment test, or more frequently if a change in circumstances or the occurrence of significant events indicate the carrying value may not be recoverable. In making this assessment, management may first consider qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. Examples of qualitative factors 63 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report include macroeconomic conditions, industry and market considerations, cost factors, overall financial performance, entity-specific events, events affecting reporting units, and sustained changes in our stock price. If results of the qualitative assessment indicate a more likely than not determination or if a qualitative assessment is not performed, a quantitative test is performed utilizing a combination of an income approach, using a discounted cash flow methodology, and a market approach, by comparing the estimated fair value of each reporting unit with its net book value. The discounted cash flow calculations are dependent on several key assumptions including the timing of future forecasted cash flows, forecasted revenue growth rates, forecasted EBITDA margin and the discount rate. The market approach uses the guideline company method, which involves calculating valuation multiples based on financial data from comparable publicly traded companies. Multiples derived from these companies provide an indication of how much a knowledgeable investor in the marketplace would be willing to pay for a company. These multiples are then applied to the financial data for our reporting units to arrive at an indication of value. To determine the reasonableness of the calculated fair values of our reporting units, we review the assumptions described to ensure neither the market approach nor the income approach yields significantly different valuations. We selected these valuation approaches because we believe the combination of these approaches, along with our best judgment regarding underlying assumptions and estimates, provides us with the best estimate of fair value of our reporting units. We perform an assessment of goodwill at the reporting unit level. We have three reporting units for purposes of goodwill evaluation. These units consist of our PC operating segment, our Railroad Products and Services reporting unit and our Utility Products reporting unit. Railroad Products and Services and Utility Products are one level below our RUPS operating segment. The Railroad Products and Services reporting unit primarily serves the rail industry in North America, and the Utility Products reporting unit serves the utility industries in the United States and Australia. For each of the three years ended December 31, 2025, we determined that the estimated fair values exceeded the carrying values of all the reporting units, and accordingly, goodwill was not impaired. The change in the carrying amount of goodwill attributable to each reporting unit was as follows: Performance Chemicals Railroad Products and Services Utility Products Total (Dollars in millions) Balance at December 31, 2023 $ 173.8 $ 41.0 $ 79.6 $ 294.4 Acquisitions 0.0 0.0 25.3 25.3 Currency translation ( 2.3 ) ( 0.1 ) ( 0.2 ) ( 2.6 ) Balance at December 31, 2024 $ 171.5 $ 40.9 $ 104.7 $ 317.1 Acquisitions 0.0 0.0 11.7 11.7 Divestitures 0.0 ( 1.2 ) 0.0 ( 1.2 ) Currency translation 1.5 0.0 0.3 1.8 Balance at December 31, 2025 $ 173.0 $ 39.7 $ 116.7 $ 329.4 Intangible assets, other than goodwill, are recorded at fair value and amortized on a straight-line basis over their estimated useful lives. We annually evaluate the remaining useful life of the intangible asset being amortized to determine whether events or circumstances warrant a revision to the remaining period of amortization. If the estimate of an intangible asset’s remaining useful life is changed, the remaining carrying amount of the intangible asset will be amortized prospectively over that revised remaining useful life. Intangible assets are also subject to testing for recoverability whenever events or changes indicate that its carrying value may not be recoverable. Our intangible assets are summarized below: December 31, Weighted average remaining life in years 2025 2024 Estimated life in years Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net (Dollars in millions) Customer contracts 9 to 18 8.5 $ 246.0 $ 142.3 $ 103.7 $ 255.0 $ 138.6 $ 116.4 Technology 4 to 12 0.6 26.3 26.2 0.1 26.3 26.1 0.2 Trademarks 4 to 18 8.2 9.9 7.0 2.9 9.2 6.8 2.4 Supply contracts 10 0 2.5 2.5 0.0 2.2 2.2 0.0 Non-compete agreements 12 0 1.6 1.6 0.0 1.6 1.6 0.0 Total 8.3 $ 286.3 $ 179.6 $ 106.7 $ 294.3 $ 175.3 $ 119.0 64 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report In 2025, the gross carrying value of intangible assets decreased by a net $ 8.0 million, due primarily to the KRS divestiture, partly offset by the Greenhill acquisition, both described in Note 3 and foreign exchange translation. Total amortization expense related to these intangible assets was $ 16.0 million, $ 15.8 million and $ 14.5 million for the years ended December 31, 2025, 2024 and 2023, respectively. Estimated amortization expense for the next five years is summarized below: Estimated annual amortization (Dollars in millions) 2026 $ 14.6 2027 14.3 2028 13.5 2029 13.3 2030 13.2 14. Pensions and Post-Retirement Benefit Plans We maintain a number of defined benefit and defined contribution plans to provide retirement benefits for employees in the United States, as well as employees outside the United States. These plans are maintained and contributions are made in accordance with the Employee Retirement Income Security Act of 1974 (ERISA), local statutory law or as determined by the board of directors. The defined benefit pension plans generally provide benefits based upon years of service and compensation. Pension plans are funded except for three domestic non-qualified defined benefit pension plans for certain key executives. In the United States, all qualified and two of the non-qualified defined benefit pension plans for salaried and hourly employees have been closed to new participants and have been frozen. Accordingly, these pension plans no longer accrue additional years of service or recognize future increases in compensation for benefit purposes. The defined contribution plans generally provide retirement assets to employee participants based upon employer and employee contributions to the participant’s individual investment account. We also provide retiree medical insurance coverage to certain U.S. employees and a life insurance benefit to most U.S. employees. For salaried employees, the retiree medical and retiree insurance plans have been closed to new participants. Expense related to defined contribution plans totaled $ 8.8 million, $ 9.4 million and $ 9.7 million for the years ended December 31, 2025, 2024 and 2023, respectively. The following table provides the components of net periodic pension costs: Year Ended December 31, Pension Benefits Other Benefits 2025 2024 2023 2025 2024 2023 (Dollars in millions) Service cost $ 1.9 $ 1.9 $ 1.6 $ 0.0 $ 0.0 $ 0.0 Interest cost 3.0 7.7 8.2 0.3 0.3 0.3 Expected return on plan assets ( 2.2 ) ( 6.0 ) ( 7.0 ) 0.0 0.0 0.0 Amortization of net loss (gain) 1.1 2.0 2.2 ( 0.4 ) ( 0.4 ) ( 0.6 ) Settlement 27.1 4.0 0.0 0.0 0.0 0.0 Net periodic benefit cost $ 30.9 $ 9.6 $ 5.0 $ ( 0.1 ) $ ( 0.1 ) $ ( 0.3 ) 65 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report The following table presents the change in the funded status of the pension and post-retirement plans: Year Ended December 31, Pension Benefits Other Benefits 2025 2024 2025 2024 (Dollars in millions) Change in benefit obligation: Benefit obligation at beginning of year $ 135.6 $ 154.3 $ 5.7 $ 6.2 Service cost 1.9 1.9 0.0 0.0 Interest cost 3.0 7.7 0.3 0.3 Actuarial (gains) losses ( 5.4 ) ( 5.1 ) 0.7 ( 0.1 ) Settlement ( 84.5 ) ( 12.0 ) 0.0 0.0 Expenses paid ( 0.9 ) 0.0 0.0 0.0 Currency translation 2.2 ( 0.5 ) 0.0 0.0 Benefits paid ( 5.7 ) ( 10.7 ) ( 1.1 ) ( 0.7 ) Benefit obligation at end of year 46.2 135.6 5.6 5.7 Change in plan assets: Fair value of plan assets at beginning of year 108.4 128.1 0.0 0.0 Actual return on plan assets 1.8 ( 5.1 ) 0.0 0.0 Employer contribution 15.1 8.7 1.1 0.7 Settlement ( 84.5 ) ( 12.0 ) 0.0 0.0 Currency translation 2.2 ( 0.6 ) 0.0 0.0 Benefits paid ( 5.7 ) ( 10.7 ) ( 1.1 ) ( 0.7 ) Fair value of plan assets at end of year 37.3 108.4 0.0 0.0 Funded status of the plan $ ( 8.9 ) $ ( 27.2 ) $ ( 5.6 ) $ ( 5.7 ) In 2025, the net actuarial gain of $ 5.4 million is due principally to the impact from the pension settlement. The actual return on plan assets was positive in 2025 primarily due to revaluation increases of $ 1.7 million in the bulk annuity insurance policies related to our defined benefit pension plans in the United States and the United Kingdom. As of December 31, 2025, the fair value of the bulk annuity insurance policies of $ 34.5 million is based on the calculated pension benefit obligation and is classified as Level 3 within the fair value hierarchy. As the calculated pension benefit obligation increased due to a decrease in the discount rate, there was a commensurate increase in the value of the bulk annuity insurance policy. During 2024, we initiated a plan to terminate our United States qualified pension plan. As a first step, we offered a lump-sum buyout to active and deferred vested participants and approximately 275 participants received lump-sum payments. This reduced the pension liability by $ 12.0 million and resulted in the recognition of a pension settlement loss of $ 4.0 million, before tax, in the fourth quarter of 2024. In 2025, we completed the irrevocable transfer of $ 84.5 million of pension liabilities and an equal amount of pension assets to an insurance company. In order to achieve this transfer, additional cash funding of approximately $ 12 million was required. In 2025, we recorded a settlement loss of approximately $ 27.1 million, before tax. In connection with the planned termination of our defined benefit pension plan in the United Kingdom, in 2021, we entered into a buy-in bulk annuity insurance policy in exchange for a premium payment of $ 67.8 million, which is subject to adjustment as a result of subsequent data cleansing activities. This pension plan has a benefit obligation of $ 30.0 million and plan assets of $ 29.4 million as of December 31, 2025. Under the terms of this buy-in insurance policy, the insurer is liable to pay the benefits of the plan, but the plan still retains full legal responsibility to pay the benefits to members using the insurance payments. The buy-in policy will be treated as a plan asset going forward until such time as the buy-in policy is converted to a buy-out policy, which is when individual insurance policies will be assigned to each member of the plan and the plan will no longer have legal responsibility to pay the benefits to the members. The data cleansing effort has been substantially completed and we expect to recognize a pre-tax pension settlement loss of approximately $ 20 million upon the pension obligation becoming irrevocably settled, the timing of which is uncertain. The timing of the conversion to a buy-out policy and related recognition of the estimated pension settlement loss has been impacted by a ruling from the High Court of Justice in the United Kingdom in the case of Virgin Media Limited v NTL Pension Trustees II Limited and Others (the "Virgin Media Case") related to certain amendments to UK pension plans. The UK government has introduced legislation to address industry wide issued resulting from the Virgin Media Case. Such legislation, if adopted, will enable us to proceed with the conversion to a buy-out policy. 66 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Plan Data Year Ended December 31, Pension Benefits 2025 2024 (Dollars in millions) Current liabilities (included in accrued liabilities on the balance sheet) $ 0.9 $ 17.9 Pension plans with projected benefit obligations in excess of plan assets: Benefit obligation $ 38.8 $ 133.8 Fair value of plan assets 29.4 106.2 Pension plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligation $ 38.7 $ 133.5 Fair value of plan assets 29.4 106.2 The measurement date for all pension and post-retirement assets and obligations is December 31 for each respective year. The accumulated benefit obligation for all defined benefit pension plans as of December 31, 2025 and 2024 was $ 46.0 million and $ 135.3 million, respectively. Expected Contributions for the 2026 Fiscal Year Our expected contributions for 2026 are estimated to be $ 0.9 million for pension plans and $ 0.6 million for other benefit plans. Projected Benefit Payments Benefit payments for pension benefits, which are primarily funded by the pension plan assets, and other benefits, which are funded by general corporate assets, are expected to be paid as follows: Pension Benefits Other Benefits (Dollars in millions) 2026 $ 3.2 $ 0.4 2027 3.2 0.4 2028 3.6 0.5 2029 3.3 0.5 2030 3.4 0.5 Next five years 19.8 2.2 Weighted-Average Assumptions December 31, Pension Benefits Other Benefits 2025 2024 2025 2024 Discount rate 5.47 % 5.51 % 5.43 % 5.77 % Expected return on plan assets 5.33 4.92 Rate of compensation increase 3.00 3.00 Initial medical trend rate 6.90 7.10 Basis for the Selection of the Long-Term Rate of Return on Assets The long-term rate of return on assets assumption was determined by using the plan’s asset allocation as described in the plan’s investment policy and modeling a distribution of compound average returns over a time horizon. The model uses asset class return, variance, and correlation assumptions to produce the expected return. The return assumptions used forward-looking gross returns influenced by the current bond yields, corporate bond spreads and equity risk premiums based on current market conditions. In general, the long-term rate of return is the sum of the portion of total assets in each asset class multiplied by the expected return for that class, adjusted for expected expenses to be paid from the assets. To develop the expected long-term rate of return on assets assumption, we considered the historical returns and the future expectations for returns for each asset class, as well as the target asset allocation of the pension portfolio. 67 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Investment Strategy The weighted average asset allocation for our pension plans by asset category is as follows: December 31, 2025 2024 Debt securities 4 % 69 % Equity securities 2 1 Other 94 30 Total 100 % 100 % Our investment strategy for our pension plans is to maintain an adequate level of diversification, to reduce interest rate and market risk and to provide adequate liquidity to meet immediate and future benefit payment requirements. As previously discussed, we entered into a buy-in bulk annuity insurance policy with respect to our defined benefit plan in the United Kingdom in anticipation of irrevocably transferring this pension liability to a third party insurance company. All assets are invested in pooled or commingled investment vehicles with the exception of the insurance annuity contracts. Our interest in these investment vehicles is expressed as a unit of account with a value per unit that is the result of the accumulated values of the underlying investments. Equity securities held within these investment vehicles are typically priced on a daily basis using the closing market price from the exchange through which the security is traded. Debt securities held within these investment vehicles are typically priced on a daily basis by independent pricing services. Certain investments are valued using the net asset value (NAV) practical expedient and have not been categorized in the fair value hierarchy but are included to reconcile the fair value hierarchy to the total fair value of plan assets. As of December 31, 2025, we had three categories of pension plan assets within the fair value hierarchy: $ 2.5 million measured at NAV, $ 34.5 million held in insurance annuity contracts (Level 3 - significant unobservable inputs) and $ 0.3 million held in cash and cash equivalents (Level 2 - significant observable inputs). As of December 31, 2024, we had three categories of pension plan assets within the fair value hierarchy: $ 76.4 million measured at NAV, $ 28.3 million held in an insurance annuity contract (Level 3 - significant unobservable inputs) and $ 3.7 million held in cash and cash equivalents (Level 2 - significant observable inputs). Incentive Plan We have short-term management incentive plans that pay cash bonuses if certain company performance goals are met. Expenses incurred for these plans were $ 6.6 million in 2025, $ 13.7 million in 2024 and $ 17.4 million in 2023. 15. Debt Weighted Average Interest Rate Maturity December 31, 2025 2024 (Dollars in millions) Credit Facility 5.65 % 2030 $ 448.0 $ 455.8 Term Loan B 6.22 % 2030 480.3 483.7 Total debt 928.3 939.5 Less current maturities of long-term debt 4.9 4.9 Less unamortized debt issuance costs 9.1 8.7 Long-term debt $ 914.3 $ 925.9 Unamortized debt issuance costs presented above are included as a deduction from the carrying amount of long-term debt. Credit Facility We have a credit agreement (the Credit Facility) with a consortium of banks. The Credit Facility provides for an $ 800.0 million revolving credit facility, a $ 50.0 million swingline facility and provides for the ability to incur one or more uncommitted incremental revolving or term loan facilities in an aggregate amount of at least $ 730.0 million, subject to applicable financial covenants. The interest rate on the Credit Facility is variable and may be based on the SOFR, which is the applicable benchmark for current borrowings, or an alternative benchmark depending on the borrowing type. In June 2025, we amended the Credit Facility to, among other things, (a) extend the maturity date of the Credit Facility to January 9, 2030 at the earliest; (b) modify the total net leverage ratio financial covenant by making the test 4.75 :1 throughout the life of the Credit Facility; and (c) modify the interest rate margins applicable to the Credit Facility by 68 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report removing the 10 basis point credit spread adjustment and increasing the total net leverage ratio test used to determine the applicable interest rate margin. Borrowings under the Credit Facility are secured by a first priority lien on substantially all of the assets (excluding real property and other customary assets) of Koppers Inc., Koppers Holdings Inc. and our material domestic subsidiaries. The Credit Facility contains certain covenants that may limit Koppers Inc. and its restricted subsidiaries from taking certain actions. These limitations include, among others, restrictions on additional indebtedness, liens, dividends, investments, acquisitions, certain distributions, asset sales, transactions with affiliates and modifications to material documents, including organizational documents. In addition, such covenants may give rise to events of default upon the failure by Koppers Inc. and its restricted subsidiaries to meet certain financial ratios. As of December 31, 2025, we had $ 344.8 million of unused revolving credit availability for working capital purposes after restrictions from certain letter of credit commitments and other covenants. As of December 31, 2025, $ 7.2 million of commitments were utilized by outstanding letters of credit. For the three years ended December 31, 2025, we incurred commitment fees between 20 and 22 basis points on the undrawn portion of our credit facility to maintain credit availability. Term Loan B In April 2023, we issued a class of senior secured term loans under the Credit Facility (the Term Loan B) which was upsized in April 2024, resulting in $ 488.0 million of aggregate net proceeds, before debt financing costs. The interest rate on the Term Loan B is variable and is based on, at our option, adjusted Term SOFR Rate or adjusted Daily Simple SOFR. The interest rate margins applicable to adjusted Term SOFR Rate or adjusted Daily Simple SOFR loans are 2.50 percent with a floor of 0.50 percent. The principal balance of the Term Loan B is repayable in quarterly installments on the last business day of each quarterly period in an amount equal to 0.25 percent of the principal amount, with the balance due at maturity on April 10, 2030. Interest Rate Swaps See Note 5 – Derivative Financial Instruments for discussion of the interest rate swap agreements, which effectively convert the variable rate to a fixed rate for a portion of our variable rate debt. Debt Maturities At December 31, 2025, the aggregate debt maturities for the next five years are as follows: (Dollars in millions) 2026 $ 4.9 2027 4.9 2028 4.9 2029 4.9 2030 916.7 Total principal debt 936.3 Less unamortized discount 8.0 Total debt $ 928.3 16. Leases We recognize lease obligations and associated right-of-use assets for existing non-cancelable leases. We have non-cancelable operating leases primarily associated with railcars, office and manufacturing facilities, storage tanks, ships, production equipment and vehicles. Many of our leases include both lease (e.g., fixed rent) and non-lease components (e.g., maintenance and services). For certain significant asset classes such as railcars, storage tanks, ships and vehicles, we have separated the lease and non-lease components based on the estimated stand-alone price for each component. For the remaining asset classes, we have elected to account for these components as a single lease component. In addition, we exclude leases expiring within twelve months from balance sheet recognition. Many of our leases include one or more options to renew. We evaluate renewal options at the lease commencement date and regularly thereafter to determine if we are reasonably certain to exercise the option, in which case we include the renewal period in our lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on information available to determine the present value of the lease payments. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. 69 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report The following table presents operating lease costs, variable lease costs and supplemental cash flow information: Year Ended December 31, 2025 2024 2023 (Dollars in millions) Operating lease costs $ 35.6 $ 31.2 $ 28.7 Variable lease costs 3.3 3.7 4.0 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflow from operating leases $ 35.3 $ 31.0 $ 39.5 The following table presents information about the amount and timing of cash flows arising from our operating leases as of December 31, 2025: (Dollars in millions) 2026 $ 32.9 2027 28.9 2028 20.3 2029 12.5 2030 7.0 Thereafter 24.4 Total lease payments 126.0 Less interest 22.7 Present value of lease liabilities $ 103.3 Supplemental information related to leases is as follows: December 31, 2025 2024 Weighted average remaining lease term, in years 5.7 4.2 Weighted average discount rate 6.7 % 6.8 % 17. Commitments and Contingent Liabilities We are involved in litigation and various proceedings relating to environmental laws and regulations, product liability and other matters. Certain of these matters are discussed below. The ultimate resolution of these contingencies is subject to significant uncertainty and should we fail to prevail in any of these legal matters or should several of these legal matters be resolved against us in the same reporting period, these legal matters could, individually or in the aggregate, be material to the consolidated financial statements. Environmental and Other Litigation Matters We are subject to federal, state, local and foreign laws and regulations and potential liabilities relating to the protection of the environment and human health and safety including, among other things, the cleanup of contaminated sites, the treatment, storage and disposal of wastes, the discharge of effluent into waterways, the emission of substances into the air and various health and safety matters. We expect to incur substantial costs for ongoing compliance with such laws and regulations. We may also face governmental or third-party claims, or otherwise incur costs, relating to cleanup of, or for injuries resulting from, contamination at sites associated with past and present operations. We accrue for environmental liabilities when a determination can be made that a liability is probable and reasonably estimable. Environmental and Other Liabilities Retained or Assumed by Others. We have agreements with former owners of certain of our operating locations under which the former owners retained, assumed and/or agreed to indemnify us against certain environmental and other liabilities. The most significant of these agreements was entered into at Koppers Inc.’s formation on December 29, 1988 (the Acquisition). Under the related asset purchase agreement between Koppers Inc. and Beazer East, subject to certain limitations, Beazer East retained the responsibility for and agreed to indemnify Koppers Inc. against certain liabilities, damages, losses and costs, including, with certain limited exceptions, liabilities under and costs to comply with environmental laws to the extent attributable to acts or omissions occurring prior to the Acquisition and liabilities related to products sold by Beazer East prior to the Acquisition (the Indemnity). Beazer Limited, the parent company of Beazer East, unconditionally guaranteed Beazer East’s performance of the Indemnity pursuant to a guarantee. The Indemnity provides different mechanisms, subject to certain limitations, by which Beazer East is obligated to indemnify Koppers Inc. with regard to certain environmental, product and other liabilities and imposes certain conditions 70 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report on Koppers Inc. before receiving such indemnification, including, in some cases, certain limitations regarding the time period as to which claims for indemnification can be brought. In July 2004, Koppers Inc. and Beazer East agreed to amend the environmental indemnification provisions of the December 29, 1988 asset purchase agreement to extend the indemnification period for pre-closing environmental liabilities, subject to the following paragraph, and agreed to share toxic tort litigation defense arising from any sites acquired from Beazer East. Qualified expenditures under the Indemnity are not subject to a monetary limit. Qualified expenditures under the Indemnity include (i) environmental cleanup liabilities required by third parties, such as investigation, remediation and closure costs, relating to pre-December 29, 1988 (Pre-Closing) acts or omissions of Beazer East or its predecessors; (ii) environmental claims by third parties for personal injuries, property damages and natural resources damages relating to Pre-Closing acts or omissions of Beazer East or its predecessors; (iii) punitive damages for the acts or omissions of Beazer East and its predecessors without regard to the date of the alleged conduct and (iv) product liability claims for products sold by Beazer East or its predecessors without regard to the date of the alleged conduct. The indemnification period ended July 14, 2019 (the Claim Deadline), and Beazer East may now tender certain third-party claims described in sections (i) and (ii) above to Koppers Inc. However, to the extent the third-party claims described in sections (i) and (ii) above were tendered to Beazer East by the Claim Deadline, Beazer East will continue to be required to pay the costs arising from such claims under the Indemnity. Furthermore, the Claim Deadline did not change the provisions of the Indemnity with respect to indemnification for non-environmental claims, such as product liability claims, which claims may continue to be tendered by Koppers Inc. to Beazer East. The Indemnity provides for the resolution of issues between Koppers Inc. and Beazer East by an arbitrator on an expedited basis upon the request of either party. The arbitrator could be asked, among other things, to make a determination regarding the allocation of environmental responsibilities between Koppers Inc. and Beazer East. Arbitration decisions under the Indemnity are final and binding on the parties. Contamination has been identified at most manufacturing and other sites of our subsidiaries. One site currently owned and operated by Koppers Inc. in the United States is listed on the National Priorities List promulgated under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA). Currently, at the properties acquired from Beazer East, which includes the National Priorities List site and all but one of which are permitted under the Resource Conservation and Recovery Act (RCRA), a significant portion of all investigative, cleanup and closure activities are being conducted and paid for by Beazer East pursuant to the terms of the Indemnity. In addition, other of Koppers Inc.’s sites are or have been operated under RCRA and various other environmental permits, and remedial and closure activities are being conducted at some of these sites. To date, the parties that retained, assumed and/or agreed to indemnify us against the liabilities referred to above, including Beazer East, have performed their obligations in all material respects. Periodically, issues have arisen between Koppers Inc. and Beazer East and/or other indemnitors that have been resolved without arbitration. Koppers Inc. and Beazer East engage in discussions from time to time that involve, among other things, the allocation of environmental costs related to certain operating and closed facilities. If for any reason (including disputed coverage or financial incapability) one or more of such parties fail to perform their obligations and we are held liable for or otherwise required to pay all or part of such liabilities without reimbursement, the imposition of such liabilities on us could have a material adverse effect on our business, financial condition, cash flows and results of operations. Furthermore, we could be required to record a contingent liability on our balance sheet with respect to such matters, which could result in a negative impact to our business, financial condition, cash flows and results of operations. Domestic Environmental Matters. Koppers Inc. has been named as one of the potentially responsible parties (PRPs) at the Portland Harbor CERCLA site located on the Willamette River in Oregon. Koppers Inc. operated a coal tar pitch terminal near the site. Koppers Inc. has responded to a US Environmental Protection Agency (the EPA) information request and has executed a PRP agreement which outlines a private process to develop an allocation of past and future costs among more than 80 parties to the site. Koppers Inc. believes it is a de minimis contributor at the site. The EPA issued its Record of Decision (ROD) in January 2017 for the Portland Harbor CERCLA site. The selected remedy includes a combination of sediment removal, capping, enhanced and monitored natural recovery and riverbank improvements. The ROD does not determine who is responsible for remediation costs. At that time, the net present value and undiscounted costs of the selected remedy as estimated in the ROD were approximately $ 1.1 billion and $ 1.7 billion, respectively. These costs will likely increase given the remedy has not and will not be implemented for several years. Responsibility for implementing and funding that work will be decided in the separate private allocation process which is ongoing. In November 2024, Koppers Inc. received a Special Notice Letter (SNL) from the EPA. The SNL was formally issued to approximately 60 parties and initiates negotiations between PRPs and the EPA for implementation of the ROD. In May 2025, Koppers Inc. submitted a response to the SNL to the EPA. 71 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report Additionally, Koppers Inc. is involved in two separate matters involving natural resource damages at the Portland Harbor site. One matter involves claims by the trustees to recover damages based upon an assessment of damages to natural resources caused by the releases of hazardous substances to the Willamette River. The assessment serves as the foundation to estimate liabilities for settlements of natural resource damages claims or litigation to recover from those who do not settle with the trustee groups. Koppers Inc. has agreed to resolve its natural resource damage liabilities for the assessment area pursuant to a consent decree lodged with the United States District Court for the District of Oregon in November 2023. The consent decree was approved by the District Court in October 2025, and one party has appealed that decision to the United States Court of Appeals for the Ninth Circuit. A second matter involves a lawsuit filed in January 2017 by the Yakama Nation in the United States District Court for the District of Oregon. Yakama Nation seeks recovery for response costs and the costs of assessing injury to natural resources to waterways beyond the current assessment area. Following the most recent court rulings, the Yakama Nation case has been stayed pending completion of the private allocation process for the Portland Harbor CERCLA site. In September 2009, Koppers Inc. received a general notice letter from the EPA notifying it that it may be a PRP at the Newark Bay CERCLA site. Koppers Inc. operated a wood treating facility near the site in Newark, New Jersey. In January 2010, Koppers Inc. submitted a response to the general notice letter asserting that Koppers Inc. is a de minimis party at this site. We have accrued the estimated costs of participating in the PRP groups at the Portland Harbor and Newark Bay CERCLA sites and estimated de minimis contributor settlement amounts at the sites totaling $ 3.9 million as of December 31, 2025. The actual cost could be materially higher as there has not been a determination of how those costs will be allocated among the PRPs at the sites. Accordingly, an unfavorable resolution of these matters may have a material adverse effect on our business, financial condition, cash flows and results of operations. There are two plant sites related to the PC business and one plant site related to the Utility and Industrial Products business in our RUPS segment in the United States where we have recorded environmental remediation liabilities for soil and groundwater contamination which occurred prior to our acquisition of the businesses. As of December 31, 2025, our estimated environmental remediation liability for these acquired sites totals $ 3.6 million. In June 2024, Koppers Inc. received a letter stating that the Illinois Attorney General’s Office (IL AGO) received an enforcement referral from the Illinois Environmental Protection Agency relating to certain alleged air emissions violations at our Stickney, IL facility. We are cooperating with IL AGO in connection with this matter. We have not provided a reserve for the Stickney, IL enforcement matter because, at this time, we cannot reasonably determine the probability of a loss, and the amount of loss, if any, cannot be reasonably estimated. The timing of a resolution to this matter cannot be reasonably determined. Although Koppers Inc. is vigorously defending this matter, an unfavorable resolution of this matter may have a material adverse effect on our business, financial condition, cash flows and results of operations. Foreign Environmental Matters. There is one plant site related to the PC business located in Australia where we have recorded an environmental remediation liability for soil and groundwater contamination which occurred prior to the acquisition of the business. As of December 31, 2025, our estimated environmental remediation liability for the acquired site totals $ 1.2 million. Environmental Reserves Rollforward. The following table reflects changes in the accrual for environmental remediation. As of December 31, 2025 and 2024, $ 1.8 million and $ 2.3 million, respectively, were classified as current liabilities . December 31, 2025 2024 (Dollars in millions) Balance at beginning of year $ 10.3 $ 10.6 Expense 0.5 0.3 Cash expenditures ( 0.4 ) ( 0.4 ) Revision of reserves ( 0.3 ) 0.0 Currency translation 0.1 ( 0.2 ) Balance at end of year $ 10.2 $ 10.3 ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE None. 72 TABLE OF CONTENTS Koppers Holdings Inc. 2025 Annual Report