What changed in this filing

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Item 1. Financial Statements

2026-08-06 compared with 2026-05-08 · 139 added, 87 removed, 618 unchanged (27% of the section changed)

3 unchanged sentences

Three Months Ended

(Dollars in millions, except share and per share amounts) (Unaudited) (Unaudited)

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions, except share and per share amounts) (Unaudited) (Unaudited) (Unaudited) (Unaudited)

Net sales $ 520.1 $ 504.8 $ 975.4 $ 961.3

3 unchanged sentences

Impairment and restructuring 215.8 17.6 223.6 37.6

(Gain) on sale of assets ( 4.3 ) ( 0.3 )

Operating profit 22.0 27.0

Loss (gain) on sale of assets 0.4 0.0 ( 3.9 ) ( 0.3 )

Operating (loss) profit ( 166.0 ) 39.1 ( 144.0 ) 66.1

Other income, net 1.0 2.1 1.9 3.5

1 unchanged sentence

Loss on pension settlement 0.0 0.0 0.0 29.0

Income (loss) before income taxes 7.9 ( 17.2 )

Income tax provision (benefit) 0.8 ( 3.3 )

Net income (loss) $ 7.1 $ ( 13.9 )

Earnings (loss) per common share:

(Loss) income before income taxes ( 180.0 ) 23.9 ( 172.1 ) 6.7

Income tax (benefit) provision ( 32.5 ) 7.5 ( 31.7 ) 4.2

Net (loss) income $ ( 147.5 ) $ 16.4 $ ( 140.4 ) $ 2.5

(Loss) earnings per common share:

Basic $ ( 7.71 ) $ 0.83 $ ( 7.26 ) $ 0.13

6 unchanged sentences

Three Months Ended

(Dollars in millions) (Unaudited) (Unaudited)

Net income (loss) $ 7.1 $ ( 13.9 )

Changes in other comprehensive income (loss):

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions) (Unaudited) (Unaudited) (Unaudited) (Unaudited)

Net (loss) income $ ( 147.5 ) $ 16.4 $ ( 140.4 ) $ 2.5

Changes in other comprehensive (loss) income:

Currency translation adjustment ( 0.7 ) 20.6 ( 6.5 ) 29.8

Cash flow hedges, net of tax of $ 0.2 , $( 0.6 ), $ 0.0 and $( 2.0 )

( 0.7 ) 1.4 0.1 4.4

Pension adjustments, net of tax of $ 0.0 , $ 0.0 , $ 0.0 and $ 8.3

Comprehensive income $ 2.4 $ 23.4

0.2 0.1 0.5 25.2

Comprehensive (loss) income $ ( 148.7 ) $ 38.5 $ ( 146.3 ) $ 61.9

The accompanying notes are an integral part of these condensed consolidated financial statements.

1 unchanged sentence

CONDENSED CONSOLIDATED BALANCE SHEET

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

(Dollars in millions, except share and per share amounts) (Unaudited)

42 unchanged sentences

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS

Three Months Ended March 31,

Six Months Ended June 30,

(Dollars in millions) (Unaudited) (Unaudited)

Cash provided by (used in) operating activities:

Net income (loss) $ 7.1 $ ( 13.9 )

Net (loss) income $ ( 140.4 ) $ 2.5

Adjustments to reconcile net income to net cash provided by operating activities:

Depreciation and amortization 37.3 36.0

Depreciation in impairment and restructuring 0.0 12.2

Impairment and depreciation in impairment and restructuring 209.7 18.0

Stock-based compensation 6.8 8.3

14 unchanged sentences

Other working capital ( 3.9 ) ( 2.9 )

Net cash provided by (used in) operating activities 46.3 ( 22.7 )

Net cash provided by operating activities 96.3 27.8

Cash (used in) provided by investing activities:

5 unchanged sentences

Net cash (used in) investing activities ( 22.4 ) ( 39.3 )

Cash provided by (used in) financing activities:

Cash (used in) provided by financing activities:

Borrowings of credit facility 358.4 271.5

3 unchanged sentences

Repurchases of Common Stock ( 43.9 ) ( 29.2 )

Payment of debt issuance costs 0.0 ( 2.1 )

Dividends paid and return of capital to noncontrolling interests ( 3.8 ) ( 3.2 )

11 unchanged sentences

Three Months Ended

(Dollars in millions, except per share amounts) (Unaudited) (Unaudited)

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions, except per share amounts) (Unaudited) (Unaudited) (Unaudited) (Unaudited)

Total equity – beginning of period $ 549.5 $ 498.3 $ 574.3 $ 489.0

8 unchanged sentences

Balance at beginning of period 544.3 474.5 539.4 490.3

Net income (loss) 7.1 ( 13.9 )

Common Stock dividends ($ 0.09 and $ 0.08 per share)

Net (loss) income ( 147.5 ) 16.4 ( 140.4 ) 2.5

Common Stock dividends

($ 0.09 , $ 0.08 , $ 0.18 and $ 0.16 per share)

( 1.8 ) ( 1.6 ) ( 3.7 ) ( 3.5 )

5 unchanged sentences

Cash flow hedges, net of tax (1)

( 0.7 ) 1.4 0.1 4.4

Pension adjustments, net of tax (2)

0.2 0.1 0.5 25.2

Balance at end of period ( 67.0 ) ( 61.2 ) ( 67.0 ) ( 61.2 )

18 unchanged sentences

Common Stock Outstanding 18,903 19,712 18,903 19,712

(1) Amounts reclassified from accumulated other comprehensive income to net income related to derivative financial instruments, net of tax, were $ 0.4 million and $ 0.6 million during the three months ended March 31, 2026 and 2025, respectively.

(1) Amounts reclassified from accumulated other comprehensive income to net income related to derivative financial instruments, net of tax, were $ 0.5 million and $ 0.9 million during the three months ended June 30, 2026 and 2025, respectively, and $ 0.9 million and $ 1.5 million during the six months ended June 30, 2026 and 2025, respectively.

(2) Amounts reclassified from accumulated other comprehensive income to net income consist of amounts shown for pension adjustments.

23 unchanged sentences

Plant Closures and Restructuring – The following table summarizes restructuring activities:

Three Months Ended March 31, 2026 Three Months Ended March 31, 2025 Cumulative Total

Three Months Ended

June 30, Six Months Ended

June 30, Cumulative Total

2026 2025 2026 2025

(Dollars in millions)

Stickney Shutdown:

Severance, retention and employee benefits $ 2.0 $ 0.0 $ 2.0 $ 0.0 $ 2.0

Impairment 164.6 0.0 164.6 0.0 164.6

Depreciation and asset disposal costs 8.5 0.0 8.5 0.0 8.5

Plant cleaning, waste disposal and demolition costs 36.4 0.0 36.4 0.0 36.4

Phthalic Anhydride Shutdown:

6 unchanged sentences

Total impairment and restructuring $ 215.8 $ 17.6 $ 223.6 $ 37.6 $ 292.4

Phthalic Anhydride Shutdown – In December 2024, we made the decision to discontinue phthalic anhydride production at our facility in Stickney, Illinois.

Stickney Shutdown – We have made the decision to discontinue distillation and chemical manufacturing operations at our Carbon Materials and Chemicals facility in Stickney, Illinois.

The decision was driven by challenging market conditions over the past decade, including unit operating costs outpacing our ability to capture higher pricing, reduced raw material supply from North American steel manufacturers and increased capital requirements.

We anticipate winding down the remaining distillation and chemical production activities by December 31, 2026 at the latest and are tentatively targeting fourth quarter 2026 for shifting production to our coal tar distillation facility located in Nyborg, Denmark.

We continue to evaluate potentially appropriate uses for the Stickney facility following the end of production activities.

Phthalic Anhydride Shutdown – In December 2024, we made the decision to discontinue phthalic anhydride production at our Carbon Materials & Chemicals 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.

We expect these combined actions to result in the following cumulative charges, which includes the amounts already spent in the above table:

Expected Totals Low High

(Dollars in millions)

Severance, retention and employee benefits (cash) $ 5.0 $ 5.0

Impairment, depreciation and asset disposal costs (non-cash) 176.0 185.0

Plant cleaning, waste disposal and demolition costs (cash) 52.0 62.0

Stickney Shutdown Total Pre-tax Charges $ 233.0 $ 252.0

Severance, retention and employee benefits (cash) $ 1.0 $ 1.0

Depreciation and asset disposal costs (non-cash) 28.0 28.0

Plant cleaning, waste disposal and demolition costs (cash) 21.0 25.0

Phthalic Anhydride Shutdown Total Pre-tax Charges $ 50.0 $ 54.0

Total Cash Charges $ 79.0 $ 93.0

Total Non-Cash Charges $ 204.0 $ 213.0

Workforce Reduction Program – In November 2024, we committed to a workforce reduction program across select U.S.

11 unchanged sentences

During this time period, we will transition incremental production to our facility in Guthrie, Kentucky.

The following table includes details of our phthalic anhydride shutdown and workforce reduction program liabilities:

Phthalic Anhydride Shutdown Workforce Reduction Program

The following table includes details of our Stickney shutdown, phthalic anhydride shutdown and workforce reduction program liabilities:

Stickney Shutdown Phthalic Anhydride Shutdown Workforce Reduction Program

(Dollars in millions)

3 unchanged sentences

Liability at December 31, 2025 $ 0.0 $ 5.4 $ 0.6

Accrual 0.5 0.0

Cash paid 0.0 ( 2.3 ) ( 0.6 )

Liability at March 31, 2026 $ 5.2 $ 0.2

Liability at June 30, 2026 $ 38.4 $ 4.4 $ 0.0

(1) Approximately $ 18.5 million of the Stickney shutdown accrual is a short-term asset retirement obligation, which is included in accrued liabilities in the condensed consolidated balance sheet.

KCCC Liquidation – In July 2024, Koppers and Tangshan Iron & Steel Group Co.

3 unchanged sentences

The following table presents the estimated fair values and the related carrying amounts of our financial instruments:

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

Fair Value Carrying Value Fair Value Carrying Value

25 unchanged sentences

Accordingly, we prospectively discontinued cash flow hedge accounting in the third quarter of 2025.

As of March 31, 2026, $ 2.0 million remained in accumulated other comprehensive income and will be released to income as the underlying hedge contracts mature through December 2026.

As of June 30, 2026, $ 1.3 million remained in accumulated other comprehensive income and will be released to income as the underlying hedge contracts mature through December 2026.

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.

2 unchanged sentences

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 condensed consolidated statement of operations.

As of March 31, 2026 and December 31, 2025, we had contracts totaling 3.6 million and 3.8 million gallons, respectively.

As of June 30, 2026 and December 31, 2025, we had contracts totaling 2.9 million and 3.8 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.

1 unchanged sentence

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.

In 2023, we entered into interest rate swap agreements with an aggregate notional amount of $ 400.0 million at a weighted average fixed Secured Overnight Financing Rate (SOFR) of 3.97 percent.

These swap agreements expire in April 2027.

During the second quarter of 2026, we entered into forward-starting interest rate swap agreements that commence in April 2027.

These swaps have aggregate notional amounts of $ 100.0 million, $ 150.0 million and $ 150.0 million, at a weighted average fixed SOFR of 4.10 percent, 4.01 percent and 3.99 percent, and expire in April 2028, April 2029 and April 2030, respectively.

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.

1 unchanged sentence

The fair value of the outstanding derivative contracts recorded in the balance sheet are as follows:

March 31, 2026

June 30, 2026

Copper Swap Contracts Heating Oil Contracts Foreign Currency Forward

19 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

4 unchanged sentences

Units Outstanding (in Pounds) Net Fair Value – Asset

March 31, 2026 December 31, 2025 March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025 June 30, 2026 December 31, 2025

(Amounts in millions)

1 unchanged sentence

Foreign Currency Forward Contracts – The net currency units outstanding for contracts were:

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

(In millions)

Australian Dollars AUD 3.2 AUD 0.0

British Pound Sterling GBP 0.0 GBP 0.3

3 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions, except share and per share amounts)

Net income (loss) $ 7.1 $ ( 13.9 )

Net (loss) income $ ( 147.5 ) $ 16.4 $ ( 140.4 ) $ 2.5

Weighted average common shares outstanding (in thousands):

2 unchanged sentences

Diluted 19,128 20,235 19,338 20,456

Earnings per common share:

(Loss) earnings per common share:

Basic $ ( 7.71 ) $ 0.83 $ ( 7.26 ) $ 0.13

2 unchanged sentences

earnings per common share 701 714 715 771

On May 7, 2026, we declared a quarterly dividend of $ 0.09 per common share, payable on June 15, 2026 to shareholders of record as of May 29, 2026.

On August 5, 2026, we declared a quarterly dividend of $ 0.09 per common share, payable on September 14, 2026 to shareholders of record as of August 28, 2026.

Stock-based Compensation

The board of directors granted restricted stock units and performance stock units (collectively, the stock units) to certain employee participants in January 2026.

The board of directors granted restricted stock units and performance stock units (collectively, the stock units) to certain employee participants in 2026.

Most grants of restricted stock units vest in three or four years .

7 unchanged sentences

If minimum performance criteria are not achieved, no performance stock units will vest.

For the awards granted in January 2026, target shares for units with a market condition totaled 124,878 and target shares for units with a performance condition totaled 137,844 .

For the awards granted in 2026, target shares for units with a market condition totaled 129,843 and target shares for units with a performance condition totaled 142,383 .

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.

These awards incorporate a fair value cap such that the number of awards that vest will be reduced if our stock price exceeds the cap at the end of the performance measurement period:

January 2026 Grant

January 2026 Grant May 2026 Grant

Grant date price per share of performance award $ 26.93 $ 41.54

15 unchanged sentences

Forfeited ( 24,882 ) ( 17,187 ) ( 42,069 ) $ 36.14

Non-vested at March 31, 2026 520,011 679,416 1,199,427 $ 32.60

Non-vested at June 30, 2026 511,422 688,920 1,200,342 $ 33.17

The following table shows a summary of the status and activity of stock options:

7 unchanged sentences

Exercised ( 77,409 ) $ 20.25

Outstanding at March 31, 2026 436,952 $ 30.12 3.59 $ 4.1

Exercisable at March 31, 2026 436,952 $ 30.12 3.59 $ 4.1

Expired ( 6,664 ) $ 32.19

Outstanding at June 30, 2026 423,057 $ 30.10 3.37 $ 6.3

Exercisable at June 30, 2026 423,057 $ 30.10 3.37 $ 6.3

The following table presents total stock-based compensation expense recognized in the condensed consolidated statement of operations:

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

10 unchanged sentences

Utility products include the pressure treatment of transmission and distribution poles for electric, telephone and broadband utilities.

In addition, we provide untreated wood products and rail joint bars, which are steel bars used to join rails together for railroads, to the railroad markets and inspection services to the utility markets.

In addition, we provide untreated wood products and rail joint bars, which are steel bars used to join rails together for railroads, to the railroad markets.

We also operate a business related to the recovery of used crossties, serving the same customer base as our North American railroad business.

4 unchanged sentences

Naphthalene is used as a surfactant in the production of concrete.

See Note 2 - Restructuring for further discussion of the discontinuation of distillation and chemical manufacturing operations in Stickney, Illinois.

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 last-in, first-out (LIFO) inventory effects, impairment, restructuring and plant closure costs, significant gains or losses on sale

of assets, mark-to-market commodity hedging, acquisition-related charges, amortization of cloud-based software implementation costs and other unusual items.

These non-cash and/or non-recurring items typically include last-in, first-out (LIFO) inventory effects, impairment, restructuring and plant closure costs, significant gains or losses on sale of assets, mark-to-market commodity hedging, acquisition-related charges, amortization of cloud-based software implementation costs and other unusual items.

This presentation is consistent with how our chief operating decision maker evaluates the results of operations and makes strategic decisions about the business.

6 unchanged sentences

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 condensed consolidated balance sheet.

Contract assets of $ 1.7 million and $ 1.8 million are recorded within accounts receivable, net of allowance within the condensed consolidated balance sheet as of March 31, 2026 and December 31, 2025, respectively.

Contract assets of $ 1.8 million for both periods are recorded within accounts receivable, net of allowance within the condensed consolidated balance sheet as of June 30, 2026 and December 31, 2025.

Segment Revenues for Significant Product Lines

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

14 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

22 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

7 unchanged sentences

( 0.7 ) ( 0.5 ) ( 1.2 ) ( 0.8 )

Gain on sale of assets 4.3 0.3

(Loss) gain on sale of assets ( 0.4 ) 0.0 3.9 0.3

Impairment, restructuring and plant closure costs (1)

1 unchanged sentence

LIFO benefit (2)

2.3 0.7 3.5 2.5

Mark-to-market commodity hedging (losses) gains ( 3.0 ) 0.7 ( 6.9 ) 9.8

2 unchanged sentences

Interest expense ( 15.0 ) ( 17.3 ) ( 30.0 ) ( 33.9 )

Income tax provision ( 0.8 ) 3.3

Net income (loss) $ 7.1 $ ( 13.9 )

Income tax benefit (provision) 32.5 ( 7.5 ) 31.7 ( 4.2 )

Net (loss) income $ ( 147.5 ) $ 16.4 $ ( 140.4 ) $ 2.5

(1) See Note 2 - Restructuring.

2 unchanged sentences

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

15 unchanged sentences

Segment Assets

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

(Dollars in millions)

8 unchanged sentences

Total $ 329.1 $ 329.4

(1) See Note 2 - Restructuring.

Effective Tax Rate – The income tax provision for interim periods is comprised of an estimated annual effective income tax rate applied to current year ordinary income and tax associated with discrete items.

These discrete items generally relate to excess stock compensation deductions, changes in tax laws, adjustments to unrecognized tax benefits and changes of estimated tax liability to the actual liability determined upon filing income tax returns.

To determine the annual effective tax rate, management is required to make estimates of annual pretax income in each domestic and foreign jurisdiction in which we conduct business.

To determine the annual effective tax rate, management is required to make estimates of annual pre-tax income in each domestic and foreign jurisdiction in which we conduct business.

Entities that have historical pre-tax losses and current year estimated pre-tax losses that are not projected to generate a future benefit are excluded from the estimated annual effective income tax rate.

3 unchanged sentences

Foreign earnings taxed at different rates ( 2.8 ) 5.5

State income taxes, net of federal tax benefit 2.3 2.5

Nondeductible expenses ( 1.1 ) 2.2

State income taxes, net of federal tax benefit 1.0 1.9

Change in tax contingency reserves ( 0.2 ) 0.3

1 unchanged sentence

Estimated annual effective income tax rate 17.9 % 31.6 %

Income taxes as a percentage of pretax income were 10.1 percent and 19.2 percent for the three months ended March 31, 2026 and 2025, respectively.

The effective income tax rate for the three months ended March 31, 2026 was lower than the 2026 estimated annual effective income tax rate due to the liquidation of our former coal tar distillation facility located in China.

This one-time non-cash gain did not have any associated income tax expense.

The effective income tax rate for the three months ended March 31, 2025 was lower than the 2025 estimated annual effective income tax rate due to the loss on pension settlement which was treated as a discrete item in the first quarter tax provision.

The estimated annual effective income tax rate for 2026 is materially lower than the estimated annual effective income tax rate for 2025 due to the Stickney shutdown tax benefit being recorded at a tax rate of approximately 23 percent, which is materially less than the tax rate that is recorded on the pre-tax income from our worldwide operations.

The estimated annual effective tax rate for 2026 is less than the federal income tax rate since the estimated result of our worldwide operations is a pre-tax loss.

The effect of the higher foreign tax rate and the other reconciling tax expense items in the above table reduce the estimated annual effective income tax rate when there is a pre-tax loss.

Income taxes as a percentage of pre-tax income were 18.1 percent and 18.4 percent for the three and six months ended June 30, 2026, respectively, and 31.4 percent and 62.7 percent for the three and six months ended June 30, 2025, respectively.

The effective income tax rate for the three and six months ended June 30, 2026 was slightly higher than the respective estimated annual effective income tax rate due to various discrete items, which were not material in the aggregate or individually.

The effective income tax rate for the three months ended June 30, 2025 was slightly lower than the respective estimated annual effective income tax rate due to various discrete items, which were not material in the aggregate or individually.

The effective income tax rate for the six months ended June 30, 2025 was significantly higher than the respective estimated annual effective income tax rate due to the loss on pension settlement, which was treated as a discrete item.

During the year, management regularly updates estimates of pre-tax income and income tax expense based on changes in pre-tax income projections by taxable jurisdiction, repatriation of foreign earnings, unrecognized tax benefits and other tax matters.

To the extent that actual results vary from these estimates, the actual annual effective income tax rate at the end of the year could be materially different from the estimated annual effective income tax rate as of the three months ended March 31, 2026.

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").

9 unchanged sentences

income tax examinations by tax authorities for years prior to 2020.

As of March 31, 2026 and December 31, 2025, unrecognized tax benefits of $ 1.1 million for both periods would affect the effective tax rate if recognized.

As of June 30, 2026 and December 31, 2025, unrecognized tax benefits of $ 1.2 million and $ 1.1 million, respectively, would affect the effective tax rate if recognized.

We do not anticipate material changes to the amount of unrecognized tax benefits within the next twelve months.

March 31, 2026 December 31, 2025

June 30, 2026 December 31, 2025

(Dollars in millions)

17 unchanged sentences

In April 2026, the UK government approved legislation to address industry wide issues resulting from the Virgin Media Case.

This legislation will enable us to proceed with the conversion to a buy-out policy.

This legislation will enable us to proceed with the conversion to a buy-out policy which is expected to be completed by the second quarter of 2027 at the latest.

The following table provides the components of net periodic benefit cost for the pension plans:

Three Months Ended

June 30, Six Months Ended

2026 2025 2026 2025

(Dollars in millions)

6 unchanged sentences

Defined contribution plan expense $ 1.7 $ 1.2 $ 4.6 $ 4.5

Weighted Average Interest Rate Maturity March 31, 2026 December 31, 2025

Weighted Average Interest Rate Maturity June 30, 2026 December 31, 2025

(Dollars in millions)

15 unchanged sentences

and its restricted subsidiaries to meet certain financial ratios.

As of March 31, 2026, we had $ 343.5 million of unused revolving credit availability after restrictions from certain letter of credit commitments and other covenants.

As of March 31, 2026, $ 7.2 million of commitments were utilized by outstanding letters of credit.

As of June 30, 2026, we had $ 350.0 million of unused revolving credit availability after restrictions from certain letter of credit commitments and other covenants.

As of June 30, 2026, $ 7.3 million of commitments were utilized by outstanding letters of credit.

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.

1 unchanged sentence

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.

A portion of 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 4 – 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.

54 unchanged sentences

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 and is expected to provide further clarification with respect to liability allocation in 2026.

In November 2024, Koppers Inc.

18 unchanged sentences

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 $ 3.7 million as of March 31, 2026.

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.

1 unchanged sentence

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 March 31, 2026, our estimated environmental remediation liability for these acquired sites totals $ 3.6 million.

As of June 30, 2026, 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.

In connection with this matter, on June 17, 2026, IL AGO filed a complaint in the Circuit Court of Cook County against Koppers Inc.

and Koppers Carbon Materials LLC alleging air emissions-related violations of state-issued permits, regulations and statutes, and seeking civil penalties, injunctive relief and IL AGO’s costs and legal fees.

Subsequent to that filing, we and IL AGO have engaged in discussions about a potential resolution to this matter, which may include a civil penalty and may require us to discontinue certain operations and withdraw our air permits at our Stickney, IL facility by agreed-upon dates, consistent with our decision to discontinue distillation and chemical manufacturing operations at the facility, as announced on May 8, 2026.

Accordingly, we have accrued our estimated liability of the probable penalty as of June 30, 2026.

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.

and Koppers Carbon Materials LLC are 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 March 31, 2026, our estimated environmental remediation liability for the acquired site totals $ 1.2 million.

As of June 30, 2026, 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 March 31, 2026 and December 31, 2025, $ 1.6 million and $ 1.8 million, respectively, were classified as current liabilities .

March 31, 2026 December 31, 2025

As of June 30, 2026 and December 31, 2025, $ 1.6 million and $ 1.8 million, respectively, were classified as current liabilities .

June 30, 2026 December 31, 2025

(Dollars in millions)

5 unchanged sentences

Balance at end of period $ 10.0 $ 10.2

Subsequent Events

On May 8, 2026, we announced that we have made a conditional decision to discontinue distillation and chemical manufacturing operations at our facility in Stickney, Illinois, subject to the satisfaction of any bargaining obligations that might exist with the union that represents certain employees at that facility.

The conditional decision, which is pending negotiations and consultation with the union, was driven by challenging market conditions over the past decade, including unit operating costs outpacing our ability to capture higher pricing, reduced raw material supply from North American steel manufacturers and increased capital requirements.

We anticipate winding down the remaining distillation and chemical production activities by December 31, 2026, pending discussions with the union.

We are tentatively targeting fourth quarter 2026 for shifting production to our coal tar distillation facility located in Nyborg, Denmark.

As part of this conditional decision, we continue to evaluate potentially appropriate uses for the Stickney facility following the end of production activities.

We expect this action to result in pre-tax charges to earnings of $ 227 million to $ 262 million through the end of 2029, $ 170 million to $ 195 million of which constitutes non-cash charges and approximately $ 57 million to $ 67 million of which constitutes cash expenditures.

Estimates of the total pre-tax amount for each major type of cost associated with the discontinuation plan are:

(i) retention and severance costs of approximately $ 5 million (including both for salaried and union employees, and pending negotiations and consultation with the union), (ii) accelerated depreciation and asset write-down costs of approximately $ 170 million to $ 195 million, and (iii) plant cleaning, waste disposal and demolition costs of approximately $ 52 million to $ 62 million.

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-Q

Item 1. Financial Statements