What changed in this filing

/stocks — the workspaceLOADING

Item 8. Financial Statements and Supplementary Data

2026-03-03 compared with 2025-03-03 · 1064 added, 519 removed, 1208 unchanged (57% of the section changed)

11 unchanged sentences

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Century Aluminum Company and subsidiaries (the "Company") as of December 31, 2024 and 2023, the related consolidated statements of operations, comprehensive income (loss), shareholders' equity, and cash flows, for each of the three years in the period ended December 31, 2024, and the related notes (collectively referred to as the "financial statements").

We have audited the accompanying consolidated balance sheets of Century Aluminum Company and subsidiaries (the "Company") as of December 31, 2025 and 2024, the related consolidated statements of operations, comprehensive (loss) income, shareholders' equity, and cash flows, for each of the three years in the period ended December 31, 2025, and the related notes (collectively referred to as the "financial statements").

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

We have also 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, 2024, 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 March 3, 2025 expressed an adverse opinion on the Company's internal control over financial reporting because of material weaknesses.

We have also 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 March 2, 2026, expressed an adverse opinion on the Company's internal control over financial reporting because of a material weakness.

Restatement of the Financial Statements

As discussed in Notes 1 and 22 to the financial statements, the accompanying 2024 and 2023 financial statements have been restated for the correction of a misstatement.

Basis for Opinion

9 unchanged sentences

We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current-period audit of the 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 financial statements and (2) involved our especially challenging, subjective, or complex judgments.

The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing a separate opinion on the critical audit matters or on the accounts or disclosures to which it relates.

Impairment of Long-Lived Assets — Refer to Note 1 to the financial statements.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the 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 financial statements and (2) involved our especially challenging, subjective, or complex judgments.

The communication of critical audit matters does not alter in any way our opinion on the 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.

Income Taxes - Refer to Note 1 and Note 16 to the financial statements

Critical Audit Matter Description

The Company reviews property, plant, and equipment (“long-lived assets”) for impairment whenever events or changes in circumstances, known as triggering events, indicate that the carrying amount of a long-lived asset or asset group, may not be recoverable.

Management considers various factors when determining if long-lived assets should be evaluated for impairment, including a significant adverse change in the business climate or industry conditions (such as sustained decreases in commodity prices, volatility in energy costs, and the global economy), a current period operating or cash flow loss combined with a history of losses, a significant adverse change in the extent or manner in which an asset is used, or a current expectation that the asset will be sold or otherwise disposed of before the end of its useful life.

We identified the identification of impairment indicators for long-lived assets as a critical audit matter because of the significant assumptions management makes when determining whether events or circumstances have occurred indicating that the carrying

amounts of property, plant and equipment may not be recoverable.

This required a high degree of auditor judgment and an increased extent of effort when performing audit procedures to evaluate whether management appropriately identified impairment indicators.

The Company regularly assesses the likelihood that deferred tax assets will be recovered from future taxable income.

To the extent the Company believes that it is more likely than not that a deferred tax asset will not be realized, a valuation allowance is established.

When a valuation allowance is established or increased, an income tax charge is included in the Consolidated Statements of Operations and net deferred tax assets are adjusted accordingly.

Future changes in tax laws, statutory tax rates and taxable income levels could result in actual realization of the deferred tax assets being materially different from the amounts provided for in the consolidated financial statements.

If the actual recovery amount of the deferred tax asset is less than anticipated, the Company would be required to write-off the remaining deferred tax asset and increase the tax provision.

We identified management’s determination that it is more likely than not that the U.S.

deferred tax assets will not be realized as

a critical audit matter because of the significant judgments and estimates management makes in evaluating the positive and negative evidence, including future taxable income.

This required a high degree of auditor judgment and an increased extent of effort, including the need to involve our income tax specialists, when performing audit procedures to evaluate the reasonableness of management’s significant judgments and estimates.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the assessment of possible indicators of impairment included the following, among others:

• We tested the effectiveness of internal controls related to management’s identification of events or circumstances that may indicate the carrying amount of long-lived assets may not be recoverable.

• We evaluated management’s analysis of impairment indicators by:

• Assessing whether asset groups having indicators of impairment were appropriately identified or considered.

• Considering industry conditions, commodity price trends and the impact of macroeconomic factors, such as adverse changes in the regulatory environment, legislation or other factors that may represent impairment indicators not previously contemplated in management’s analysis.

• Evaluating management’s judgements around historical trends, macroeconomic and industry conditions, and whether forecasts are consistent with the Company’s operating strategy.

• Evaluating reasonableness of management’s assessment of future market prices of the revenue-generating commodity and future input costs necessary for operations by comparing these against available forward market pricing data.

• Inspecting minutes of the board of directors and committees of executive management to understand if there were factors that would represent potential impairment indicators for the Company’s asset groups.

Our audit procedures related to the assessment of the U.S.

valuation allowance included the following, among others:

• We tested the effectiveness of internal controls over deferred tax assets, including controls related to management’s determination of whether or not it is more likely than not that the deferred tax assets may not be recoverable.

• Obtained an understanding of management’s process to assess the U.S.

deferred tax assets for realizability including how management analyzed its significant assumptions’ sensitivity to change.

• Evaluated the reasonableness of the methods, assumptions, and judgments used by management to determine whether a valuation allowance was necessary.

• With the assistance of our income tax specialists, we evaluated the positive and negative evidence used in management’s assessment including but not limited to the following:

◦ Considering industry conditions, commodity price trends and the impact of macroeconomic factors, such as adverse changes in the regulatory environment, legislation, historical fluctuations in market prices of the revenue-generating commodity, future market prices, or other factors that may impact the realizability of the deferred tax assets.

◦ Considering management’s history of carrying out its stated plans.

◦ Evaluating whether management’s judgments and estimates were consistent with evidence obtained in other areas of the audit.

◦ Inspecting minutes of the board of directors and committees of executive management to understand if there were factors that would indicate management’s assumptions are not reasonable.

/s/ Deloitte & Touche LLP

6 unchanged sentences

We have audited the internal control over financial reporting of Century Aluminum Company and subsidiaries (the “Company”) 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 (COSO).

In our opinion, because of the effect of the material weaknesses identified below on the achievement of the objectives of the control criteria, the Company has not maintained effective internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control — Integrated Framework (2013) issued by COSO.

In our opinion, because of the effect of the material weakness identified below on the achievement of the objectives of the control criteria, the Company has not maintained effective internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control — Integrated Framework (2013) issued by COSO.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated financial statements as of and for the year ended December 31, 2025, of the Company and our report dated March 2, 2026, expressed an unqualified opinion on those financial statements.

15 unchanged sentences

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.

Material Weaknesses

Material Weakness

A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the company’s annual or interim financial statements will not be prevented or detected on a timely basis.

The following material weaknesses have been identified and included in management's assessment:

Management identified a material weakness related to the failure to design and implement appropriate information technology controls in the areas of logical access controls including provisioning, deprovisioning, privileged access, user access review, application changes and monitoring relating to its Jamalco JV.

Management identified that the Company's Jamalco JV failed to design and implement appropriate business process level controls, including controls to address the completeness and accuracy of information derived from its affected information technology systems, which resulted in a material weakness related to reconciliation controls and insufficient review controls related to inventories, accounts payable, cost of goods sold and property, plant, and equipment.

These material weaknesses were considered in determining the nature, timing, and extent of audit tests applied in our audit of the consolidated financial statements as of and for the year ended December 31, 2024, of the Company, and this report does not affect our report on such financial statements.

The following material weakness has been identified and included in management's assessment:

Management identified deficiencies in the design and operating effectiveness of (1) business process level controls at its Jamalco joint venture, including reconciliation controls and insufficient review controls related to inventories, accounts payable, accrued expenses, cost of goods sold and property, plant, and equipment, and (2) financial reporting controls over the consolidation of the Jamalco joint venture.

These deficiencies constitute a material weakness in internal control over financial reporting.

This material weakness was considered in determining the nature, timing, and extent of audit tests applied in our audit of the consolidated financial statements as of and for the year ended December 31, 2025, of the Company, and this report does not affect our report on such financial statements.

/s/ Deloitte & Touche LLP

6 unchanged sentences

2025 2024 2023

(As Restated) (As Restated)

Related parties $ 1,365.5 $ 1,312.1 $ 1,612.1

5 unchanged sentences

Selling, general and administrative expenses 79.9 56.8 44.3

Asset impairment — — 159.4

Other operating expense - net 6.8 15.8 —

Operating income (loss) 121.4 31.8 ( 150.2 )

Other operating expenses - net

18.4 6.8 15.8

Operating income 158.1 108.4 27.5

Interest expense - nonaffiliates

( 41.9 ) ( 36.4 ) ( 33.7 )

Interest expense - affiliates ( 5.8 ) ( 6.7 ) ( 1.8 )

Interest expense ( 36.4 ) ( 33.7 ) ( 29.3 )

Interest income 9.2 2.1 2.0

Net gain (loss) on forward and derivative contracts - nonaffiliates 2.5 ( 62.4 ) 210.4

Net (loss) gain on forward and derivative contracts - nonaffiliates ( 94.7 ) 2.5 ( 62.4 )

Net gain (loss) on forward and derivative contracts - affiliates — ( 0.5 ) 0.6

( 0.5 ) 0.6 ( 13.3 )

Loss on early extinguishment of debt ( 7.7 ) — —

Bargain purchase gain — 245.9 —

Other income (loss) - net ( 4.5 ) ( 3.3 ) 15.3

Other expense - net ( 14.5 ) ( 5.5 ) ( 3.3 )

Income (loss) before income taxes 2.7 309.8 ( 71.1 )

1 unchanged sentence

Income (loss) before equity in earnings of joint ventures 15.8 306.6 ( 56.5 )

Equity in losses of joint ventures 0.10 ( 0.1 ) ( 0.1 )

Equity in earnings (losses) of joint ventures — 0.1 ( 0.1 )

Net income (loss) 15.8 306.7 ( 56.6 )

4 unchanged sentences

(1) Including purchases from related party of $ 294.0 million, $ 277.9 million and $ 181.4 million for the years ended December 31, 2025, 2024 and 2023, respectively.

INCOME (LOSS) ATTRIBUTABLE TO CENTURY STOCKHOLDERS PER COMMON SHARE:

Net income (loss) attributable to Century stockholders per common share:

Basic $ 0.42 $ 3.44 $ ( 0.47 )

9 unchanged sentences

2025 2024 2023

(As Restated) (As Restated)

Comprehensive income (loss):

Net income (loss) $ 15.8 $ 306.7 $ ( 56.6 )

Other comprehensive (loss) before income tax effect:

Net loss on foreign currency cash flow hedges reclassified as income ( 0.2 ) ( 0.1 ) ( 0.2 )

Other comprehensive income (loss) before income tax effect:

Net gain on foreign currency cash flow hedges reclassified as income ( 0.1 ) ( 0.2 ) ( 0.1 )

Defined benefit plans and other postretirement benefits:

Net loss arising during the period ( 11.9 ) ( 10.1 ) ( 5.9 )

OPEB curtailment gain, net — — ( 8.9 )

Net gain (loss) arising during the period 42.0 ( 13.1 ) ( 19.2 )

Amortization of prior service benefit during the period 0.2 0.2 0.1

Amortization of net loss during the period 6.5 6.2 4.8

Other comprehensive (loss) before income tax effect

( 5.4 ) ( 3.9 ) ( 11.4 )

Amortization of net gain (loss) during the period 6.0 6.5 6.2

Other comprehensive income (loss) before income tax effect 48.1 ( 6.6 ) ( 13.0 )

Income tax effect — — —

Other comprehensive (loss)

( 5.4 ) ( 3.9 ) ( 11.7 )

Other comprehensive income (loss) 48.1 ( 6.6 ) ( 13.0 )

Comprehensive income (loss) 63.9 300.1 ( 69.6 )

5 unchanged sentences

(in millions)

(As Restated)

Cash and cash equivalents $ 134.2 $ 32.9

18 unchanged sentences

Derivative liabilities 58.2 4.4

Deferred credit - preliminary bargain purchase gain — 273.4

Current debt due to affiliates — 10.0

Carbon credit repurchase liability 28.6 —

Current maturities of long-term debt 68.8 70.9

4 unchanged sentences

Other liabilities 104.9 92.6

Due to affiliates - less current portion — —

Deferred taxes 58.4 71.2

19 unchanged sentences

2025 2024 2023

(As Restated) (As Restated)

CASH FLOWS FROM OPERATING ACTIVITIES:

Net income (loss) $ 15.8 $ 306.7 $ ( 56.6 )

Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:

Lower of cost or NRV inventory adjustment 2.3 — 39.6

Unrealized (gain) loss on derivative instruments ( 5.0 ) 87.1 ( 201.5 )

Adjustments to reconcile Net income (loss) to net cash provided by (used in) operating activities:

Unrealized loss (gain) on derivative instruments 62.8 ( 5.0 ) 87.1

Depreciation, depletion and amortization 91.8 86.7 79.0

Change in deferred tax (benefit) provision ( 1.3 ) ( 30.8 ) 44.2

Asset impairment — — 159.4

Share-based compensation 47.0 15.4 6.6

Loss on early extinguishment of debt 7.7 — —

Change in deferred tax provision ( 13.7 ) ( 1.3 ) ( 30.8 )

Gain on sale of assets — ( 2.3 ) —

1 unchanged sentence

Force majeure settlement — ( 12.3 ) —

Other postretirement benefits gain, net — — ( 8.9 )

Lower of cost or NRV inventory adjustment 8.6 2.3 —

Net periodic benefit cost 12.1 15.7 13.5

Other non-cash items - net 7.4 ( 4.1 ) ( 16.7 )

9 unchanged sentences

Accrued and other current liabilities 11.6 4.0 —

Ravenswood retiree legal settlement ( 2.0 ) ( 2.0 ) ( 2.0 )

Ravenswood retiree medical settlement ( 2.0 ) ( 2.0 ) ( 2.0 )

PBGC settlement ( 2.4 ) ( 0.3 ) ( 4.5 )

Other - net ( 13.2 ) ( 1.9 ) 2.8

Net cash (used in) provided by operating activities ( 24.6 ) 105.6 25.9

Net cash provided by (used in) operating activities 185.0 ( 24.6 ) 105.6

CASH FLOWS FROM INVESTING ACTIVITIES:

Purchase of property, plant and equipment ( 82.3 ) ( 95.0 ) ( 86.3 )

Proceeds from co-tenancy assets at Jamalco JV 12.7 — —

Capital expenditures ( 100.2 ) ( 82.3 ) ( 95.0 )

Proceeds from sale of property, plant and equipment — 2.3 25.7

2 unchanged sentences

CASH FLOWS FROM FINANCING ACTIVITIES:

Repayment of Senior Notes due 2028 ( 250.0 ) — —

Early redemption premiums paid ( 4.7 ) — —

Proceeds from issuance of Senior Notes due 2032 400.0 — —

Payment of deferred financing fees ( 6.3 ) — —

Borrowings under revolving credit facilities 883.2 735.4 656.9

Repayments under revolving credit facilities ( 876.1 ) ( 705.1 ) ( 758.2 )

Debt issuance cost — — ( 1.5 )

Borrowings under Grundartangi casthouse debt facility 25.0 55.0 50.0

Repayments on casthouse facility ( 6.8 ) — —

Borrowings under Iceland term facility — — 14.5

Repayments under Iceland term facility — ( 1.2 ) ( 13.5 )

Borrowings under Grundartangi casthouse debt facility — 25.0 55.0

Repayments under Grundartangi casthouse debt facility ( 123.2 ) ( 6.8 ) —

Borrowings under Vlissingen facility agreement — — 10.0

Repayments under Vlissingen facility agreement ( 10.0 ) — —

Contributions from joint venture partner 19.9 12.7 —

Payments related to tax withholding for share-based compensation ( 17.5 ) — —

Carbon credit proceeds 28.1 — 36.8

9 unchanged sentences

2025 2024 2023

(As Restated) (As Restated)

Supplemental Cash Flow Information:

1 unchanged sentence

Interest $ 36.6 $ 36.0 $ 35.2

Taxes, net of refunds 14.5 5.9 0.9

Income taxes, net of refunds 4.8 14.5 5.9

Non-cash investing activities:

1 unchanged sentence

Capitalized interest — 3.4 6.0

Distribution of fixed assets to NCI 17.0 — —

See notes to consolidated financial statements .

1 unchanged sentence

CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY

(in millions)

(in millions, except shares)

Preferred stock Common stock Additional paid-in capital Treasury stock, at cost Accumulated other comprehensive loss Accumulated

3 unchanged sentences

Net loss — — — — — — — ( 43.1 ) ( 43.1 ) ( 13.5 ) ( 56.6 )

Other comprehensive income (loss) — — — — — — ( 11.7 ) — ( 11.7 ) — ( 11.7 )

Other comprehensive loss — — — — — — ( 3.9 ) — ( 3.9 ) ( 9.1 ) ( 13.0 )

Share-based compensation — — 208,867 — 3.3 — — — 3.3 — 3.3

Conversion of preferred stock to common stock ( 1,570 ) — 157,019 — — — — — — — —

Balance, December 31, 2022 53,854 — 92,323,978 $ 1.0 $ 2,539.6 $ ( 86.3 ) $ ( 94.0 ) $ ( 1,961.0 ) $ 399.3 $ — $ 399.3

Net loss — — — — — — — ( 43.1 ) ( 43.1 ) ( 9.2 ) ( 52.3 )

Other comprehensive income (loss) — — — — — — ( 3.9 ) — ( 3.9 ) — ( 3.9 )

Noncontrolling interest of business acquired 1

— — — — — — — — — 170.2 170.2

Balance, December 31, 2023 (As Restated) 52,284 — 92,689,864 $ 1.0 $ 2,542.9 $ ( 86.3 ) $ ( 97.9 ) $ ( 2,004.1 ) $ 355.6 $ 147.6 $ 503.2

Net income (loss) — — — — — — — 336.8 336.8 ( 30.1 ) 306.7

Other comprehensive loss — — — — — — ( 5.4 ) — ( 5.4 ) ( 1.2 ) ( 6.6 )

Share-based compensation — — 341,771 — 7.3 — — — 7.3 — 7.3

Conversion of preferred stock to common stock ( 2,569 ) — 256,930 — — — — — — — —

Noncontrolling interest — — — — — — — — — ( 2.3 ) ( 2.3 )

Balance, December 31, 2023 52,284 — 92,689,864 $ 1.0 $ 2,542.9 $ ( 86.3 ) $ ( 97.9 ) $ ( 2,004.1 ) $ 355.6 $ ( 11.5 ) $ 344.1

Noncontrolling interest of business acquired 1

— — — — — — — — — ( 5.3 ) ( 5.3 )

Balance, December 31, 2024 (As Restated) 49,715 — 93,288,565 $ 1.0 $ 2,550.2 $ ( 86.3 ) $ ( 103.3 ) $ ( 1,667.3 ) $ 694.3 $ 111.0 $ 805.3

Net income (loss) — — — — — — — 41.8 41.8 ( 26.0 ) 15.8

2 unchanged sentences

Conversion of preferred stock to common stock ( 49,715 ) — 4,971,509 0.1 — — — — 0.1 — 0.1

Noncontrolling interest — — — — — — — — — ( 4.0 ) ( 4.0 )

Contributions from noncontrolling interest — — — — — — — — — 39.3 39.3

Balance, December 31, 2025 — $ — 98,969,007 $ 1.1 $ 2,571.5 $ ( 86.3 ) $ ( 55.2 ) $ ( 1,625.5 ) $ 805.6 $ 124.3 $ 929.9

1 In 2023 the Company acquired a 55 % interest in a joint venture, Jamalco.

See Note 2 to the notes to the consolidated financial statements for additional information

See notes to consolidated financial statements.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

1 unchanged sentence

Summary of Significant Accounting Policies

Organization — Century Aluminum Company ("Century Aluminum," "Century," the "Company", "we", "us", "our" or "ours") is a holding company, whose principal subsidiaries are Nordural ehf (together with its subsidiaries, "Nordural"), Century Aluminum Sebree LLC ("Century Sebree"), Century Aluminum of South Carolina ("CASC") and Century Kentucky, Inc.

("CASC") and Century Kentucky, Inc.

Nordural Grundartangi ehf, a subsidiary of Nordural, operates a primary aluminum smelter in Grundartangi, Iceland ("Grundartangi").

Century Sebree operates a primary aluminum smelter in Robards, Kentucky ("Sebree").

CASC operates a primary aluminum reduction smelter in Goose Creek, South Carolina ("Mt.

CAKY owns a primary aluminum smelter in Hawesville, Kentucky ("Hawesville").

CASC operates a primary aluminum smelter in Goose Creek, South Carolina ("Mt.

CAKY owned a primary aluminum smelter in Hawesville, Kentucky ("Hawesville"), which was sold on February 2, 2026.

Subsequent Events for additional information on the sale.

In addition to our primary aluminum assets, we have a 55 % joint venture interest in the Jamalco bauxite mining operation and alumina refinery in Jamaica ("Jamalco").

2 unchanged sentences

Carbon anodes are used in the production of primary aluminum, and Vlissingen currently supplies carbon anodes to Grundartangi.

As of December 31, 2024, Glencore owns 42.9 % of Century’s outstanding common stock ( 45.8 % on a fully-diluted basis assuming the conversion of all of the Series A Convertible Preferred Stock) and all of our outstanding Series A Convertible Preferred Stock.

Shareholders' Equity for a full description of our outstanding Series A Convertible Preferred Stock.

As of December 31, 2025, Glencore owns 36.4 % of Century’s outstanding common stock.

Century and Glencore enter into various transactions from time to time such as the purchase and sale of primary aluminum, purchase and sale of alumina and raw materials, tolling agreements as well as forward financial contracts and borrowing and other debt transactions.

14 unchanged sentences

Jamalco is a VIE.

See Note 21 .

V ariable Interest Entity .

Variable Interest Entity .

Revenue recognition — See Note 5.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

2 unchanged sentences

The carrying amount of cash equivalents approximates fair value.

Accounts Receivable and Due from Affiliates — These amounts are net of an allowance for expected losses of $ 0.5 million at both December 31, 2024 and 2023.

Accounts Receivable and Due from Affiliates — These amounts are net of an immaterial allowance for expected losses.

Inventories — Our inventories are stated at the lower of cost or net realizable value, using the first-in, first-out ("FIFO") and the weighted average cost method.

3 unchanged sentences

Additions and improvements are capitalized when each asset is placed into service.

Asset and accumulated depreciation accounts are relieved for dispositions with resulting gains or losses included in Other income (loss) - net.

Asset and accumulated depreciation accounts are relieved for dispositions with resulting gains or losses included in Other expense - net.

Maintenance and repairs are expensed as incurred.

9 unchanged sentences

Mineral reserves are amortized on a units-of-production basis.

Impairment of long-lived assets — The Company reviews property, plant and equipment ("long-lived assets") for impairment whenever events or changes in circumstances, known as triggering events, indicate that the carrying amount of a long-lived asset or an asset group may not be recoverable.

Impairment of long-lived assets — The Company reviews property, plant and equipment and right of use assets ("long-lived assets") for impairment whenever events or changes in circumstances, known as triggering events, indicate that the carrying amount of a long-lived asset or an asset group may not be recoverable.

Management considers various factors when determining if long-lived assets should be evaluated for impairment, including a significant adverse change in the business climate or industry conditions (such as sustained decreases in commodity prices, volatility in energy costs, and the global economy), a current period operating or cash flow loss combined with a history of losses, a significant adverse change in the extent or manner in which an asset is used or a current expectation that the asset will be sold or otherwise disposed of before the end of its useful life.

3 unchanged sentences

If deemed unrecoverable, an impairment loss would be recognized for the amount by which the carrying amount exceeds the estimated fair value of the long-lived asset or asset group.

Leases — We determine whether an arrangement is a lease at the inception of the arrangement based on the terms and conditions in the contract.

A contract contains a lease if there is an identified asset which we have the right to control.

Leases — We enter into operating lease contracts, as assessed at the inception of the arrangement, for real estate, automobiles, and mobile equipment.

We use our incremental borrowing rate as the basis for the discount rate used to calculate the right of use asset ("ROUA") and lease liability.

The incremental borrowing rate is determined on a lease-by-lease basis.

The terms of our leases vary, including the lease term and the ability to renew or extend certain leases.

As part of determining the lease term and potential extensions for purposes of calculating the ROUA and lease liability, we consider our historical practices related to renewal of certain leases.

We have made a policy election not to separate lease and non-lease components within contracts.

We have also elected not to recognize the impact of short term leases in the right of use asset ("ROUA") and right of use liability ("ROUL") balances.

We have also elected not to recognize the impact of short term leases in the ROUA and lease liability balances.

Short term leases are leases that have a lease term less than one year and do not include a purchase option.

Income Taxes — We account for income taxes using the asset and liability method, whereby deferred income taxes reflect the net tax effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

In evaluating our ability to realize deferred tax assets, we use judgment to determine if it is more likely than not that some portion or all of a deferred tax asset will not be realized, and if a corresponding valuation allowance is required.

CENTURY ALUMINUM COMPANY

In evaluating our ability to realize deferred tax assets, we use judgment to

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Defined Benefit Pension and Other Postretirement Benefits — We sponsor defined benefit pension and OPEB plans for certain of our domestic hourly and salaried employees and a supplemental executive retirement benefit plan for certain current and former executive officers.

determine if it is more likely than not that some portion or all of a deferred tax asset will not be realized, and if a corresponding valuation allowance is required.

Defined Benefit Pension and Other Postretirement Benefits — We sponsor defined benefit pension and Other Postretirement Benefit ("OPEB") plans for certain of our domestic hourly and salaried employees and a supplemental executive retirement benefit plan for certain current and former executive officers.

Plan assets and obligations are measured annually or more frequently if there is a re-measurement event, based on the Company’s measurement date utilizing various actuarial assumptions.

2 unchanged sentences

Actuarial gains or losses are recorded in Accumulated other comprehensive income (loss).

Net periodic benefit cost is a component of Cost of goods sold;

Selling, general and administrative expenses and Other expense - net.

We contribute to our defined benefit pension plans based upon actuarial and economic assumptions designed to achieve adequate funding of the projected benefit obligations and to meet the minimum funding requirements.

2 unchanged sentences

We recognize the estimated future cost of providing postemployment benefits on an accrual basis over the active service life of the employee.

Net periodic benefit cost is a component of Cost of goods sold;

Selling, general and administrative expenses and Other expense - net.

Derivatives and Hedging — As a global producer of primary aluminum, our operating results and cash flows from operations are subject to risk of fluctuations in the market prices of primary aluminum.

4 unchanged sentences

Our derivatives are not designated as cash flow hedges.

Derivative and hedging instruments are recorded in due from affiliates, derivative assets, other assets, due to affiliates, derivative liabilities and derivative liabilities - less current portion in the Consolidated Balance Sheets at fair value.

Derivative and hedging instruments are recorded in Derivative assets, Other assets, Derivative liabilities and Derivative liabilities - less current portion in the Consolidated Balance Sheets at fair value.

We value our derivative and hedging instruments using quoted market prices and other significant unobservable inputs.

We recognize changes in fair value and settlements of derivative instruments in net gain (loss) on forward and derivative contracts in the Consolidated Statements of Operations as they occur.

We recognize changes in fair value and settlements of derivative instruments in Net (loss) gain on forward and derivative contracts - nonaffiliates and Net gain (loss) on forward and derivative contracts - affiliates in the Consolidated Statements of Operations as they occur.

Unrealized gains on forward and derivative contracts are reported as part of cash flows from operations in the Consolidated Statements of Cash Flows.

3 unchanged sentences

dollar as their functional currency, as contracts for sales of aluminum and alumina and purchases of alumina and power are denominated in U.S.

Transactions denominated in currencies other than the functional currency are recorded based on exchange rates at the time such transactions arise and any transaction gains and losses are reflected in Other income (loss) - net in the Consolidated Statements of Operations.

Transactions denominated in currencies other than the functional currency are recorded based on exchange rates at the time such transactions arise and any transaction gains and losses are reflected in Other expense - net in the Consolidated Statements of Operations.

Financial Instruments — Receivables, certain life insurance policies, payables, borrowings under revolving credit facilities and debt related to industrial revenue bonds ("IRBs") are carried at amounts that approximate fair value.

Earnings per share — Basic earnings (loss) per share ("EPS") amounts are calculated by dividing earnings (loss) available to common stockholders by the weighted average number of common shares outstanding using the two-class method.

Under the two-class method, net income is allocated between shares of common stock and other participating securities based on their participating rights.

Net loss is not allocated to other participating securities if they are not obligated to share in the losses based on their contractual terms.

Diluted earnings per share is calculated by dividing net income attributable to common shareholders by the weighted average number of common and dilutive common equivalent shares outstanding during the period.

Common equivalent shares are not included in the denominator of the diluted loss per share calculation when inclusion of such shares would be anti-dilutive.

CENTURY ALUMINUM COMPANY

Earnings per share — Basic earnings (loss) per share ("EPS") amounts are calculated by dividing Net income (loss) allocated to common stockholders by the weighted average number of common shares outstanding using the two-class method.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The dilutive effect to earnings per share is determined using the "if converted" method whereby, if the conversion of the convertible notes would be dilutive, interest expense on the outstanding notes is added back to the diluted earnings numerator and all of the potentially dilutive shares are included in the diluted common shares outstanding denominator for the computation of diluted earnings per share.

Diluted EPS is calculated by dividing Net income (loss) allocated to common stockholders by the weighted average number of common and dilutive common equivalent shares outstanding during the period.

Dilutive common equivalent shares are calculated using the more dilutive of either the if-converted or two-class methods.

Our Series A Convertible Preferred Stock is a non-cumulative perpetual participating convertible preferred stock with no set dividend preferences.

8 unchanged sentences

Our limited customer base increases our concentrations of credit risk with respect to trade receivables.

We routinely assess the financial strength of our customers and collectability of our trade receivables and recognize an allowance based on our estimate of lifetime expected credit losses in accordance with the current expected credit loss ("CECL") model.

Share-Based Compensation — We measure the cost of employee services received in exchange for an award of equity instruments based on the fair value of the award on the grant date.

5 unchanged sentences

We have not issued any stock options since 2009.

Reclassification — Certain amounts in the prior period financial statements have been reclassified to conform to the presentation of the current period financial statements.

These immaterial reclassifications had no effect on the previously reported net income or net cash flows.

Restatement of Financial Statements

Subsequent to the issuance of our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, the Company identified an error in its historical financial statements related to its accounting for the consolidation of its Jamalco joint venture whereby the Company previously used the proportionate method of consolidation for certain of Jamalco's net assets versus the full consolidation method.

The Company determined that corrections to the financial statements for the impacts of this change were required for all impacted prior periods presented in this Form 10-K.

Therefore, the Company has reflected these corrections in the consolidated financial statements for the periods presented in this Form 10-K and the consolidated financial statements previously included in each of the Company's Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025 and September 30, 2025.

Additionally, current and prior period amounts in the applicable notes to the consolidated financial statements have been corrected.

Re statement of Previously Issued Financial Statements and Note 23.

Quar t er ly Fi n an cial Information (Unaudited and Rest ated).

Recent accounting pronouncements

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2023-07, Segment Reporting (Topic 280):

Improvements to Reportable Segment Disclosures, that requires disclosure of significant segment expenses that are regularly reviewed by the chief operating decision maker and included within each reported measure of segment profit or loss.

The standard also requires disclosure of the composition of other segment items included in the measure of segment profit or loss that are not separately disclosed.

The new standard is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024.

Early adoption is permitted.

We adopted this accounting standard for our fiscal year beginning January 1, 2024, retrospectively.

Therefore, prior periods have been updated to conform with the current period presentation.

Business S egments for our reportable segment disclosures.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740):

Improvements to Income Tax Disclosures, that requires presentation of specific categories of reconciling items, as well as reconciling items that meet a quantitative threshold, in the reconciliation between the income tax provision and the income tax provision using statutory tax rates.

The standard also requires disclosure of income taxes paid disaggregated by jurisdiction with separate disclosure of income taxes paid to individual jurisdictions that meet a quantitative threshold.

The amendments in this accounting standard are effective for fiscal years beginning after December 15, 2024, on a prospective basis.

Early adoption and retrospective application are permitted.

We do not expect the adoption of this accounting standard to have an impact on our consolidated financial statements, but will require certain additional disclosures.

The Company plans to adopt this guidance on its consolidated financial statements and related disclosures for the annual period ending December 31, 2025.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40):

The standard also requires disclosure of income taxes paid disaggregated by jurisdiction with separate disclosure of income taxes paid to individual jurisdictions that meet a quantitative threshold.

The amendments in this accounting standard are effective for fiscal years beginning after December 15, 2024.

The Company adopted this guidance for the 2025 annual reporting period on a prospective basis, resulting in additional disclosures within Note 16.

Income Taxes .

In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40m as amended by ASU 2025-01):

Disaggregation of Income Statement Expenses, that requires disclosure of the amounts of purchases of inventory, employee compensation, depreciation, and intangible asset amortization included in each relevant expense line item on the income statement.

4 unchanged sentences

We do not expect any impact to the consolidated financial statements, but the standard will require certain additional disclosures in the notes to the consolidated financial statements and the Company plans to adopt this guidance for the annual period ending December 31, 2027.

In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832):

Accounting for Government Grants Received by Business Entities, which adds guidance on the recognition, measurement and presentation of government grants.

The new standard is effective for fiscal years beginning after December 15, 2028.

Early adoption is permitted.

The Company has previously analogized to IAS 20, Accounting for Government Grants and Disclosure of Government Assistance , to account for refundable tax credits as an income grant.

The Company's policy on income grants under IAS 20 aligns with the updated guidance, and the Company does not expect a material effect on its consolidated financial statements upon adoption.

Acquisition of Jamalco

7 unchanged sentences

The Company finalized its purchase accounting as of March 31, 2024.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The following table summarizes the estimated fair value of identified assets acquired, liabilities assumed and noncontrolling interest at the date of acquisition:

16 unchanged sentences

Bargain purchase gain $ 245.9

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

For the twelve months ended December 31, 2023, Jamalco contributed $ 150.3 million to our total revenues and a loss of $ 45.4 million to our total earnings.

7 unchanged sentences

In August 2022, we fully curtailed production at the Hawesville facility.

We continue to explore all options related to the Hawesville facility.

For the year ended December 31, 2024, we incurred curtailment charges of $ 6.8 million, These charges were partially offset by income related to scrap and materials sales of $ 0.5 million.

For the year ended December 31, 2024, we incurred curtailment charges of $ 6.8 million.

These charges were partially offset by income related to scrap and materials sales of $ 0.5 million.

Comparatively, for the year ended December 31, 2023, we incurred curtailment charges of $ 16.6 million, including $ 9.0 million related to demand capacity charges for power.

These charges were partially offset by income related to scrap and material sales of $ 1.7 million.

For the year ended December 31, 2025, we incurred no additional curtailment charges or income.

On February 2, 2026, we completed the sale of Hawesville.

Subsequent Events for additional information on sales to the sale.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Related Party Transactions

3 unchanged sentences

Glencore ownership

As of December 31, 2024, Glencore plc and its affiliates (together "Glencore") beneficially owned 42.9 % of Century’s outstanding common stock ( 45.8 % on a fully-diluted basis assuming the conversion of all of the Series A Convertible Preferred Stock) and all of our outstanding Series A Convertible Preferred Stock.

Shareholders' Equity for a full description of our outstanding Series A Convertible Preferred Stock.

As of December 31, 2025, Glencore plc and its affiliates (together "Glencore") beneficially owned 36.4 % of Century’s outstanding common stock.

In November 2025, Glencore sold 9,000,000 shares of Century's common stock.

Due to the sale and in accordance with automatic conversion features of the Series A Convertible Preferred Stock, the remaining Series A Convertible Preferred Stock held by Glencore was converted into common stock.

Century and Glencore enter into various transactions from time to time such as the purchase and sale of primary aluminum, purchase and sale of alumina and other raw materials, tolling agreements as well as forward financial contracts and borrowing and other debt transactions.

6 unchanged sentences

For the years ended December 31, 2025, 2024 and 2023 we recorded $ 206.6 million , $ 191.3 million , and $ 191.7 million o f revenue related to alumina sales to Glencore, respectively.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Purchases from Glencore

2 unchanged sentences

Financial contracts with Glencore

We have certain financial contracts with Glencore.

From time to time, we enter into certain financial contracts with Glencore.

Derivatives regarding these forward financial sales contracts.

6 unchanged sentences

(1) Includes settlements of financial contract positions.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Vlissingen Credit Facility

6 unchanged sentences

Carbon Credit Repurchase Agreement

On September 28, 2023, our wholly owned subsidiary Nordural Grundartangi ehf ("Grundartangi"), entered into a structured repurchase arrangement with an affiliate of Glencore pursuant to which it sold 390,000 European Union Allowances ("Carbon Credits") at a price of € 82.18 per Carbon Credit, for an aggregate amount of € 32.1 million.

Pursuant to the terms of the transaction, Grundartangi will repurchase the same number of Carbon Credits at a price of € 83.72 per Carbon Credit, for an aggregate amount of € 32.7 million.

On December 18, 2023, the repurchase arrangement was amended to extend the repurchase window and increase the repurchase price to € 85.13 per Carbon Credit, for an aggregate amount of € 33.2 million.

Also on December 18, 2023, Grundartangi sold an additional 40,000 Carbon Credits at a price of € 69.30 per Carbon Credit and will repurchase the same number of Carbon Credits at a price of € 70.71 per Carbon Credit for an aggregate amount of € 2.8 million.

In March 2024, the Amended Agreement was amended to extend the repurchase window from March 25, 2024 to August 30, 2024 and the repurchase price was revised to € 87.01 per Carbon Credit, for an aggregate amount of € 33.9 million.

In addition, the Second Agreement was amended to extend the repurchase window from March 25, 2024 to August 30, 2024 and revised the repurchase price to € 72.59 per Carbon Credit, for an aggregate amount of € 2.9 million.

In August 2024, the Amended Agreement was amended to extend the repurchase window from August 30, 2024 to December 27, 2024 for 370,700 Carbon Credits.

The repurchase price was revised to € 71.20 per Carbon Credit, for an aggregate amount of € 26.4 million.

In addition, 59,300 Carbon Credits were settled on August 30, 2024 for an aggregate amount of € 11.1 million.

CENTURY ALUMINUM COMPANY

In September 2023, our wholly owned subsidiary Nordural Grundartangi ehf ("Grundartangi"), entered into a structured repurchase arrangement with Glencore and sold 390,000 European Union Allowances ("Carbon Credits") at a price of € 82.18 per Carbon Credit, for an aggregate amount of € 32.1 million (the "Original Carbon Credit Agreement").

Pursuant to the terms of the Original Carbon Credit Agreement, Grundartangi would repurchase the same number of Carbon Credits at a price of € 83.72 per Carbon Credit, for an aggregate amount of € 32.7 million.

The Original Carbon Credit Agreement was amended in December 2023, March 2024, August 2024 and December 2024, in each case to extend the repurchase window and increase the repurchase price (collectively, the "Amended Carbon Credit Agreement").

The Amended Carbon Credit Agreement (i) settled 19,300 Carbon Credits, (ii) extended the repurchase window from December 2024 to August 2025 for the remaining 370,700 Carbon Credits and (iii) revised the repurchase price to € 69.16 per Carbon Credit, for an aggregate amount of € 25.6 million.

In August 2025, all 370,700 Carbon Credits subject to the Amended Carbon Credit Agreement were settled in full.

On December 2023, Grundartangi also entered into a second structured repurchase agreement with Glencore pursuant to which it sold 40,000 Carbon Credits at a price of € 69.30 per Carbon Credit and agreed to repurchase the same number of Carbon Credits at a price of € 70.71 per Carbon Credit for an aggregate amount of € 2.8 million (the "Second Carbon Credit Agreement").

In March 2024 and August 2024, the Second Carbon Credit Agreement was amended to (i) increase the number of Carbon Credits subject to the Second Carbon Agreement by 19,300 credits, (ii) extend the repurchase window from March 2024 to August 2024 with respect to all 59,300 Carbon Credits and (iii) revise the purchase price to € 186.74 per Carbon Credit, for an aggregate amount of € 11.1 million.

In August 2024, all 59,300 Carbon Credits subject to the Second Carbon Credit Agreement were settled in full.

Due to the repurchase element of these transactions, the Company retained substantially all of the remaining benefits of the assets and has accounted for the transaction as a financing arrangement in accordance with Revenue from Contracts with Customers Topic of the FASB ASC 606.

We enter into contracts to sell mainly primary aluminum to our customers.

Revenue is recognized when our performance obligations with our customers are satisfied.

Our obligations under the contracts are satisfied when we transfer control of our primary aluminum or alumina to our customers which is generally upon shipment or delivery to customer directed locations.

The amount of consideration we receive, thus the revenue we recognize, is a function of volume delivered, market price of primary aluminum, which is based on the LME, plus regional premiums and any value-added product premiums or alumina which is based on the alumina pricing index, plus Atlantic differential.

The payment terms and conditions in our contracts vary and are not significant to our revenue.

We complete an appropriate credit evaluation for each customer at contract inception.

Customer payments are due in arrears and are recognized as Accounts receivable - net and due from affiliates in our Consolidated Balance Sheets.

In connection with our sales agreements with certain customers, including Glencore, we invoice the customer prior to physical shipment of goods for a majority of production generated from each of our U.S.

domestic smelters.

For those sales, revenue is recognized only when the customer has specifically requested such treatment and has made a commitment to purchase the product.

The goods must be complete, ready for shipment and separated from other inventory with control over the goods passing to the customer.

We must retain no further performance obligations.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

In December 2024, the Amended Agreement was amended to extend the repurchase window from December 27, 2024 to August 22, 2025 for 370,700 Carbon Credits.

The repurchase price was revised to € 69.16 per Carbon Credit, for an aggregate amount of € 25.6 million.

Due to the repurchase element of these transactions, the Company retains substantially all of the remaining benefits of the assets and has accounted for the transaction as a financing arrangement in accordance with Topic 606, Revenue from Contracts with Customers ("ASC 606").

Contract liabilities are recorded when cash payments are received or due in advance of performance.

As of December 31, 2025, and 2024, amounts recorded in Due to affiliates were $ 31.2 million and $ 41.2 million, respectively.

We disaggregate our revenue by geographical region as follows:

10 unchanged sentences

Total $ 2,527.9 $ 2,220.3 $ 2,185.4

We enter into contracts to sell mainly primary aluminum to our customers.

Revenue is recognized when our performance obligations with our customers are satisfied.

Our obligations under the contracts are satisfied when we transfer control of our primary aluminum to our customers which is generally upon shipment or delivery to customer directed locations.

The payment terms and conditions in our contracts vary and are not significant to our revenue.

We complete an appropriate credit evaluation for each customer at contract inception.

Customer payments are due in arrears and are recognized as accounts receivable - net and due from affiliates in our Consolidated Balance Sheets.

domestic smelters.

For those sales, revenue is recognized only when the customer has specifically requested such treatment and has made a commitment to purchase the product.

The goods must be complete, ready for shipment and separated from other inventory with control over the goods passing to the customer.

We must retain no further performance obligations.

Contract liabilities are recorded when cash payments are received or due in advance of performance.

As of December 31, 2024, and 2023, amounts recorded in Due to affiliates were $ 41.2 million and $ 30.6 million, respectively.

We are a lessee in various agreements for the lease of office space, land, automobiles, and mobile equipment.

All of our leases are considered operating leases.

The terms of our leases vary, including the lease term and the ability to renew or extend certain leases.

As part of determining the lease term and potential extensions for purposes of calculating the ROUA and ROUL, we consider our historical practices related to renewal of certain leases.

The weighted average remaining lease term for our

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

operating leases was 10.1 years as of December 31, 2024 and 11.8 years as of December 31, 2023.

The weighted average remaining lease term for our operating leases was 9.2 years as of December 31, 2025 and 10.1 years as of December 31, 2024.

Certain lease payment amounts are variable in nature and change periodically based on the local market consumer price index.

We use our incremental borrowing rate as the basis for the discount rate used to calculate the ROUA and ROUL, respectively, for our operating leases.

The incremental borrowing rate is determined on a lease-by-lease basis and is based on the rate of interest that we would have to pay to borrow on a collateralized basis over a similar term for an amount equal to our lease payments.

We consider the most likely financing options available for each lease based on the leased asset, legal entity party to the lease, economic environment in which the lease is denominated, the market conditions relative to the leased asset and our historical practices of obtaining financing for similar types of costs.

The weighted average discount rate for our operating leases was 7.4 % as of December 31, 2025 and 7.5 % as of December 31, 2024.

Our ROUA and ROUL balances for the years ended December 31, 2024 and December 31, 2023 were as follows (in millions):

Our ROUA and lease liability balances for the years ended December 31, 2025 and December 31, 2024 were as follows:

$ 24.4 $ 21.0

ROUL - current (2)

ROUL - non-current (3)

Total ROUL $ 21.7 $ 24.2

Lease liability - current (2)

Lease liability - non-current (3)

Total lease liability

$ 24.6 $ 21.7

(1) ROUA was recorded as part of Other Assets within non-current assets at December 31, 2025 and 2024.

(2) ROUL - current was recorded as part of Accrued and other current liabilities within Current liabilities at December 31, 2024 and 2023.

(3) ROUL - non-current was recorded as part of Other liabilities within Non-current liabilities at December 31, 2024 and 2023.

The undiscounted maturities of our operating lease liability balances as of December 31, 2024 are as follows (in millions):

(2) Lease liability - current was recorded as part of Accrued and other current liabilities within current liabilities at December 31, 2025 and 2024.

(3) Lease liability - non-current was recorded as part of Other liabilities within non-current liabilities at December 31, 2025 and 2024.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The undiscounted maturities of our operating lease liability balances as of December 31, 2025 are as follows:

Thereafter 16.8

Interest ( 10.6 )

Lease liability

During 2025 and 2024, we entered into new lease obligations, which resulted in $ 3.7 million and $ 2.0 million of additional right of use assets, respectively.

During 2023, we acquired $ 2.4 million of right of use assets related to lease obligations assumed from the Jamalco acquisition.

Total operating expense includes the following (in millions):

Total operating expense includes the following:

2025 2024 2023

Operating leases expense $ 5.6 $ 5.3 $ 4.9

Short term lease expense 3.3 3.2 0.6

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

$ 8.9 $ 8.5 $ 5.5

(1) Total lease expense is included in Cost of goods sold and Selling, general, and administrative expenses on the Consolidated Statements of Operations.

We had cash outflows of $ 5.0 million and $ 4.6 million for amounts included in the ROUL balance at the beginning of the year related to our operating leases for the years ended December 31, 2024 and December 31, 2023, respectively.

We had cash outflows of $ 5.3 million, $ 5.0 million and $ 4.6 million for amounts included in the lease liability balance at the beginning of the year related to our operating leases for the years ended December 31, 2025, 2024 and 2023, respectively.

Fair Value Measurements

9 unchanged sentences

• Level 3 Inputs – unobservable inputs for the asset or liability.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Recurring Fair Value Measurements As of December 31, 2025

16 unchanged sentences

These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The following section describes the valuation techniques and inputs used for fair value measurements categorized within Level 2 of the fair value hierarchy:

13 unchanged sentences

As of the years ending December 31, 2025, and December 31, 2024, there were no Level 3 assets and liabilities.

The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis.

For the twelve months ended December 31, 2023 and 2024 Level 3 Assets Level 3 Liabilities

LME forward financial sales contracts LME forward financial sales contracts

Balance as of January 1, 2023 $ 1.8 $ ( 4.6 )

Transfers out of Level 3 (1)

Balance as of December 31, 2023 $ — $ —

Transactions during 2024 $ — $ —

Balance as of December 31, 2024 $ — $ —

Change in unrealized gains (losses) 2023 (2)

Change in unrealized gains (losses) 2024 (2)

(1) Transfer out of Level 3 due to period of time remaining in derivative contract.

(2) Gains and losses are presented in the Consolidated Statements of Operations within the line item "Net gain (loss) on forward and derivative contracts."

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

5 unchanged sentences

Grundartangi Casthouse Facility — 9.0

Iceland Term Facility

Vlissingen Facility Agreement (5)

Debt classified as non-current liabilities:

Grundartangi casthouse facility, net of financing fees of $ 0.0 million at December 31, 2024 (4)

Grundartangi Casthouse Facility — 114.2

Vlissingen Facility Agreement (4)

7.5 % senior secured notes due April 1, 2028, net of financing fees of $ 1.9 million at December 31, 2024, interest payable semiannually

7.5 % senior secured notes due April 1, 2028

2.75 % convertible senior notes due May 1, 2028, net of financing fees of $ 0.8 million at December 31, 2025, interest payable semiannually

6.875 % senior secured notes due August 1, 2032, net of financing fees of $ 5.9 million at December 31, 2025, interest payable semiannually

Total $ 548.3 $ 528.2

6 unchanged sentences

(4) We incur interest at a base rate plus applicable margin as defined within the agreement.

The interest rate at December 31, 2024 was 8.06 %.

(5) We incur interest at a base rate plus applicable margin as defined within the agreement.

The interest rate at December 31, 2024 was 7.99 %

The interest rate at December 31, 2025 w as 7.56 %

6.875 % Senior Secured Notes due 2032

On April 14, 2021, we issued $ 250.0 million in aggregate principal amount of 7.5 % senior secured notes due 2028 (the "2028 Notes").

On July 22, 2025, we issued $ 400.0 million in aggregate principal amount of 6.875 % senior secured notes due 2032 (the "Notes").

We received proceeds of $ 393.7 million, after payment of certain financing fees and related expenses.

Interest Rate.

The 2028 Notes bear interest semi-annually in arrears on April 1 and October 1 of each year, beginning on October 1, 2021, at a rate of 7.5 % per annum in cash.

The 2028 Notes mature on April 1, 2028.

The 2032 Notes bear interest semi-annually in arrears on February 1 and August 1 of each year, beginning on February 1, 2026, at a rate of 6.875 % per annum in cash.

The 2032 Notes mature on August 1, 2032.

The 2032 Notes are senior secured obligations of Century, ranking equally in right of payment with all existing and future senior indebtedness of Century, but effectively senior to unsecured debt to the extent of the value of collateral.

1 unchanged sentence

Our obligations under the 2032 Notes and the Guarantor Subsidiaries' obligations under the guarantees are secured by a pledge of and lien on (subject to certain exceptions):

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

(i) all of our and the Guarantor Subsidiaries' property, plant and equipment (other than certain excluded property);

1 unchanged sentence

(iii) proceeds of the foregoing.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Under certain circumstances, the indenture and the security documents governing the 2032 Notes will permit us and the Guarantors to incur additional debt that also may be secured by liens on the collateral that are equal to or have priority over the liens securing the 2032 Notes.

1 unchanged sentence

Redemption Rights.

Prior to April 1, 2024, we may redeem the 2028 Notes, in whole or in part, at a redemption price equal to 100.00 % of the principal amount plus a make-whole premium and accrued and unpaid interest, and if redeemed during the twelve-month period beginning on April 1 of the years indicated below, at the following redemption prices plus accrued and unpaid interest:

Prior to August 1, 2028, we may redeem the 2032 Notes, in whole or in part, at a redemption price equal to 100.00 % of the principal amount plus a make-whole premium and accrued and unpaid interest, and if redeemed during the twelve-month period beginning on August 1 of the years indicated below, at the following redemption prices plus accrued and unpaid interest:

Year Percentage

15 unchanged sentences

Although we use quoted market prices for identical debt instruments, the markets on which they trade are not considered to be active and are therefore considered Level 2 fair value measurements.

7.5 % Senior Secured Notes due 2028

On July 22, 2025, we determined that all conditions precedent to the redemption (the “Redemption”) of our 2028 Notes pursuant to its Conditional Notice of Full Redemption issued on July 21, 2025 had been satisfied.

Accordingly, the 2028 Notes were redeemed on August 5, 2025, at an aggregate redemption price of $ 261.1 million, consisting of 101.875 % of the principal due and payable on the 2028 Notes plus accrued and unpaid interest to but excluding the August 5, 2025, redemption date.

In connection with the Redemption, effective July 22, 2025, the Company satisfied and discharged all its obligations under and in accordance with the terms of the indenture governing the 2028 Notes.

Based on the characteristics of the 2028 Notes and the 2032 Notes that were issued, the redemption of the 2028 Notes were accounted for as an extinguishment.

Accordingly, we have recorded a $ 6.2 million loss on early extinguishment of debt, consisting of early redemption premiums of $ 4.7 million and a write-off of deferred financing costs associated with the 2028 Notes of $ 1.5 million.

2.75 % Convertible Notes due 2028

1 unchanged sentence

The Convertible Notes were issued at a price of 100 % of their aggregate principal amount.

We received proce eds of $ 83.7 million, a fter payment of certain financing fees and related expenses.

We received proceeds of $ 83.7 million, after payment of certain financing fees and related expenses.

The initial conversion rate for the Convertible Notes is 53.3547 shares of the Company's common stock per $1,000 principal amount of Convertible Notes, which is equivalent to an initial conversion price of approximately $ 18.74 per share of the Company's common stock.

The conversion rate and conversion price are subject to customary adjustments under certain circumstances in accordance with the terms of the indenture.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Interest Rate.

5 unchanged sentences

and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Redemption rights.

We may not redeem the Convertible Notes prior to May 6, 2025.

On or after May 6, 2025, we may redeem for cash all or part of the Convertible Notes at our option if the last reported sale price of our common stock has been at least 130 % of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading-day period (including the last trading day of such period) ending on and including the trading day immediately preceding the date on which we provide notice of redemption, at a redemption price equal to 100 % of the principal amount of the Convertible Notes to be redeemed, plus accrued and unpaid interest.

2 unchanged sentences

Additionally, in the event of a corporate event constituting a fundamental change (as defined in the indenture), holders of the Convertible Notes may require us to repurchase all or a portion of their Convertible Notes at a repurchase price equal to 100 % of the principal amount of the Convertible Notes being repurchased, plus accrued and unpaid interest to, but excluding, the date of the fundamental change repurchase.

As of December 31, 2024, the if-converted value of the Convertible Notes did not exceed the outstanding principal amount.

As of December 31, 2025, the if-converted value of the Convertible Notes exceeded the outstanding principal amount.

As of December 31, 2025, the total estimated fair value of the Convertible Notes was $ 181.9 million.

5 unchanged sentences

revolving credit facility, increasing our borrowing capacity to $ 250.0 million, including up to $ 150.0 million under a letter of credit sub-facility.

revolving credit facility matures on June 14, 2027.

On July 22, 2025, we further amended the U.S.

revolving credit facility to, among other items, extend the maturity date of the facility to July 22, 2030 and revise the calculation of Term SOFR Adjustment to 0.10 % per annum for all interest periods.

Any letters of credit issued and outstanding under the U.S.

revolving credit facility reduce our borrowing availability on a dollar-for-dollar basis.

At December 31, 2024, there were $ 20.0 million outstanding borrowings and $ 63.7 million of outstanding letters of credit issued under our U.S.

At December 31, 2025, there were no outstanding borrowings and $ 50.5 million of outstanding letters of credit issued under our U.S.

revolving credi t facility.

12 unchanged sentences

revolving credit facility is limited by a specified borrowing base consisting of the Borrower's accounts receivable and inventory which meet the eligibility criteria.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The Borrowers' obligations under the U.S.

8 unchanged sentences

For standby letters of credit, we are required to pay a fee on the face amount of such letters of credit that varies depending on whether the letter of credit exposure is cash collateralized.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Prepayments .

8 unchanged sentences

Iceland Revolving Credit Facility

Our wholly-owned subsidiary, Nordural Grundartangi ehf ("Grundartangi"), entered into a revolving credit facility agreement with Landsbankinn hf., dated November 2013, as amended (the "Iceland revolving credit facility") which originally provided for borrowings of up to $ 50.0 million in the aggregate.

On February 4, 2022, we amended the Iceland revolving credit facility and increased the facility amount to $ 80.0 million in the aggregate.

On September 28, 2022, we further amended the Iceland revolving credit facility and increased the facility amount to $ 100.0 million in aggregate.

Our wholly-owned subsidiary, Nordural Grundartangi ehf ("Grundartangi"), entered into a revolving credit facility agreement with Landsbankinn hf., as amended (the "Iceland revolving credit facility") which provides for borrowings of up to $ 100.0 million in the aggregate.

Under the terms of the Iceland revolving credit facility, when Grundartangi borrows funds it will designate a repayment date, which may be any date prior to the maturity of the Iceland revolving credit facility.

14 unchanged sentences

Any outstanding borrowings may be prepaid without penalty or premium in whole or in part.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The Iceland revolving credit facility contains customary covenants, including restrictions on mergers and acquisitions, dispositions of assets, compliance with permits, laws and payment of taxes, as well as a covenant that requires Grundartangi to maintain a certain minimum equity ratio.

2 unchanged sentences

Upon the occurrence of an event of default, commitments under the Iceland revolving credit facility may be terminated and amounts outstanding may be accelerated and declared immediately due and payable.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Grundartangi Casthouse Facility

On November 2, 2021, in connection with the casthouse project at Grundartangi, we entered into an eight-year Term Facility Agreement with Arion Bank hf, to provide for borrowings up to $ 130.0 million (the "Casthouse Facility").

Under the Casthouse Facility, repayments of principal amounts will be made in equal quarterly installments equal to 1.739 % of the principal amount, the first payment occurring in July 2024, with the remaining 60 % of the principal amount to be paid no later than the termination date in December 2029.

As of December 31, 2024, there were $ 123.2 million in outstanding borrowings under the Casthouse Facility.

Grundartangi's obligations under the Casthouse Facility are secured by a general bond on an aggregate of $ 430.0 million in assets and rights related to Grundartangi.

Interest Rates and Fees .

The interest rate shall be at a base rate plus the applicable margin as set forth in the agreement.

Grundartangi shall pay an arrangement fee equal to 0.78 % of the total facility amount, 50 % of which was paid upfront and 50 % to be paid at the end of the availability period, and shall pay a commitment fee of 0.38 % per annum on undrawn commitments, payable quarterly at the same time as interest payments are due and payable.

Prepayments .

We can make prepayments of amounts outstanding under the Casthouse Facility, in whole or in part, without premium or penalty, together with accrued interest on the amount prepaid and subject to standard breakage costs, if applicable.

The Casthouse Facility contains customary covenants, including restrictions on mergers and acquisitions, indebtedness, preservation of assets, and dispositions of assets, as well as a covenant that requires Grundartangi to maintain a certain minimum equity ratio.

Events of Default.

The Casthouse Facility also includes customary events of default, including nonpayment, loss of license, cessation of operations, unlawfulness, breach of covenant, bankruptcy, change of ownership, certain judgments and certain cross defaults.

Upon the occurrence of an event of default, commitments under the Casthouse facility may be terminated and amounts outstanding may be accelerated and declared immediately due and payable.

Iceland Term Facility

Our wholly-owned subsidiary, Grundartangi, entered into a Term Facility Agreement with Arion Bank hf, dated September 2022, (the "Iceland Term Facility") to provide for borrowings up to € 13.6 million.

Repayments of principal amounts were made in equal monthly installments, the first payment occurring in February 2023, with the remainder of the principal amount paid in January 2024.

Borrowings under the Iceland Term Facility bore interest at a rate equal to 3.2 % plus EUR EURIBOR 1 month as published by the European Money Markets Institute.

As of December 31, 2024, the Iceland Term Facility has been repaid in full and has terminated pursuant to its terms.

In October 2025, we fully repaid all outstanding borrowings under the Casthouse Facility, which totaled $ 116.4 million in outstanding borrowings and $ 1.9 million in interest.

As a result, the Casthouse Facility has been extinguished, and we recorded a $ 1.5 million loss on early extinguishment of debt, consisting of a write-off of deferred financing costs.

Vlissingen Credit Facility

2 unchanged sentences

Pursuant to the terms of the Vlissingen Credit Facility, Vlissingen may borrow from time to time up to $ 90 million in one or more loans.

As of December 31, 2024, there was $ 10.0 million in outstanding borrowings under the Vlissingen Facility Agreement.

As of December 31, 2025, there was no outstanding borrowings under the Vlissingen Facility Agreement.

Vlissingen’s obligations under the Vlissingen Credit Facility are secured by liens on the ground lease on which Vlissingen’s facilities are located, Vlissingen’s moveable assets, financial assets, receivables and other assets, and Vlissingen’s shares.

2 unchanged sentences

The Fixed Rate is only applicable to borrowings made on or before December 1, 2024, after which the Variable Rate shall apply to all borrowings under the Vlissingen Credit Facility.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Any outstanding borrowings may be prepaid without penalty or premium in whole or in part without any charge, fee premium or penalty.

4 unchanged sentences

Covenant Compliance

As of December 31, 2024, we and our subsidiaries were in compliance with all covenants or maintained availability above applicable covenant triggers.

As of December 31, 2025, we and our subsidiaries were in compliance with all financial covenants or maintained availability above applicable covenant triggers.

Hancock County Industrial Revenue Bonds

2 unchanged sentences

The IRBs are secured by a letter of credit issued under our U.S revolving credit facility and mature in April 2028.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Surety Bond Facility

12 unchanged sentences

In addition, issuance of any shares of preferred stock with voting powers may dilute the voting power of the outstanding common stock.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Series A Convertible Preferred Stock

1 unchanged sentence

In 2008, we issued 160,000 shares of our Series A Convertible Preferred Stock.

Glencore holds all of the issued and outstanding Series A Convertible Preferred Stock.

At December 31, 2024 and December 31, 2023, 49,715 shares and 52,284 shares were outstanding, respectively.

The issuance of common stock under our stock incentive programs, debt exchange transactions and any stock offering that excludes Glencore participation triggers anti-dilution provisions of the preferred stock agreement and results in the automatic conversion of Series A Convertible Preferred Stock shares into shares of common stock.

The conversion of preferred to common shares is 100 shares of common for each share of preferred stock.

Our Series A Convertible Preferred Stock has a par value of $ 0.01 per share.

Dividend Rights.

So long as any shares of our Series A Convertible Preferred Stock are outstanding, we may not pay or declare any dividend or make any distribution upon or in respect of our common stock or any other capital stock ranking, on a parity with or junior to, the Series A Convertible Preferred Stock in respect of dividends or liquidation preference, unless we, at the same time, declare and pay a dividend or distribution on the shares of Series A Convertible Preferred Stock (a) in an amount equal to the amount such holders would receive if they were the holders of the number of shares of our common stock into which their shares of Series A Convertible Preferred Stock are convertible as of the record date fixed for such dividend or distribution, or (b) in the case of a dividend or distribution on other capital stock ranking on a parity with or junior to the Series A Convertible Preferred Stock in such amount and in such form as (based on the determination of holders of a majority of the Series A Convertible Preferred Stock) will preserve, without dilution, the economic position of the Series A Convertible Preferred Stock relative to such other capital stock.

Voting Rights.

The Series A Convertible Preferred Stock has no voting rights for the election of directors or on other matters where the shares of common stock have voting rights.

However, we may not change the powers, preferences, or rights given to the Series A Convertible Preferred Stock, or authorize, create or issue any additional shares of Series A Convertible Preferred Stock without the affirmative vote of the holders of a majority of the shares of Series A Convertible Preferred Stock then outstanding (voting separately as a class).

Liquidation Rights.

Upon any liquidation, dissolution, or winding-up of Century, the holders of shares of Series A Convertible Preferred Stock are entitled to receive a preferential distribution of $ 0.01 per share out of the assets available for distribution.

In addition, upon any liquidation, dissolution or winding-up of Century, if our assets are sufficient to make any distribution to the holders of the common stock, then the holders of shares of Series A Convertible Preferred Stock are also entitled to share ratably with the holders of common stock in the distribution of Century’s assets (as though the holders of Series A Convertible Preferred Stock were holders of that number of shares of common stock into which their shares of Series A Convertible Preferred Stock are convertible).

However, the amount of any such distribution will be reduced by the amount of the preferential distribution received by the holders of the Series A Convertible Preferred Stock.

Transfer Restrictions.

Glencore is prohibited from transferring shares of Series A Convertible Preferred Stock to any party other than an affiliate who agrees to become bound by certain agreements associated with these shares.

Automatic Conversion.

The Series A Convertible Preferred Stock automatically converts, without any further act of Century or any holders of Series A Convertible Preferred Stock, into shares of common stock, at a conversion ratio of 100 shares of common stock for each share of Series A Convertible Preferred Stock, upon the occurrence of any of the following automatic conversion events:

• If we sell or issue shares of common stock or any other stock that votes generally with our common stock, or the occurrence of any other event, including a sale, transfer or other disposition of common stock by Glencore, as a result of which the percentage of voting stock held by Glencore decreases, an amount of Series A Convertible Preferred Stock will convert to common stock to restore Glencore to its previous ownership percentage;

• If shares of Series A Convertible Preferred Stock are transferred to an entity that is not an affiliate of Glencore, such shares of Series A Convertible Preferred Stock will convert to shares of our common stock, provided that such transfers may only be made pursuant to an effective registration statement;

• Upon a sale of Series A Convertible Preferred Stock by Glencore in a Rule 144 transaction in which the shares of Series A Convertible Preferred Stock and our common stock issuable upon the conversion thereof are not directed to

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

any purchaser, such shares of Series A Convertible Preferred Stock sold will convert to shares of our common stock;

• Immediately prior to and conditioned upon the consummation of a merger, reorganization or consolidation to which we are a party or a sale, abandonment, transfer, lease, license, mortgage, exchange or other disposition of all or substantially all of our property or assets, in one or a series of transactions where, in any such case, all of our common stock would be converted into the right to receive, or exchanged for, cash and/or securities, other than any transaction in which the Series A Convertible Preferred Stock will be redeemed.

Optional Conversion.

Glencore has the option to convert the Series A Convertible Preferred Stock in a tender offer or exchange offer, at the same conversion ratio as above, in which a majority of the outstanding shares of our common stock have been tendered by the holders thereof and not duly withdrawn at the expiration time of such tender or exchange offer, so long as the Series A Convertible Preferred Stock is tendered or exchanged in such offer.

Stock Combinations – Adjustments.

If, at any time while the Series A Convertible Preferred Stock is outstanding, Century combines outstanding common stock into a smaller number of shares, then the number of shares of common stock issuable on conversion of each share of Series A Convertible Preferred Stock will be decreased in proportion to such decrease in the aggregate number of shares of common stock outstanding.

Redemptions or Repurchases of Common Stock.

We may not redeem or repurchase our common stock unless we redeem or repurchase, or otherwise make a payment on, a pro-rata number of shares of the Series A Convertible Preferred Stock.

These restrictions do not apply to our open market repurchases or our repurchases pursuant to our employee benefit plans.

Right of Redemption.

The Series A Convertible Preferred Stock will be redeemed by Century if any of the following events occur (at a redemption price based on the trading price of our common stock prior to the announcement of such event) and Glencore votes its shares of our common stock in opposition to such events:

• We propose a merger, reorganization or consolidation, sale, abandonment, transfer, lease, license, mortgage, exchange or other disposition of all or substantially all of our property or assets where any of our common stock would be converted into the right to receive, or exchanged for, assets other than cash and/or securities traded on a national stock exchange or that are otherwise readily marketable, or

• We propose to dissolve and wind up operations and any assets, other than cash and/or securities traded on a national stock exchange or that are otherwise readily marketable, are to be distributed to the holders of our common stock.

Glencore held all of the issued and outstanding Series A Convertible Preferred Stock.

At December 31, 2024, 49,715 shares were outstanding.

In November 2025, Glencore sold 9,000,000 shares of our common stock.

Due to the sale, and in accordance with automatic conversion features of the Series A Convertible Preferred Stock, the remaining Series A Convertible Preferred Stock held by Glencore were converted into common stock.

As of December 31, 2025, there were no shares outstanding.

The conversion of preferred to common shares was 100 shares of common for each share of preferred stock.

Our Series A Convertible Preferred Stock had a par value of $ 0.01 per share.

Stock Repurchase Program

7 unchanged sentences

The difference between the cost of the shares and the reissuance price is added to or deducted from additional paid-in capital.

Through December 31, 2024, we repurchased 7,186,521 shares of common stock for an aggregate purchase price of $ 86.3 million.

We have made no repurchases since April 2015 and have approximately $ 43.7 million remaining under the repurchase program authorization as of December 31, 2024.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Through December 31, 2025, we repurchased 7,186,521 shares of common stock for an aggregate purchase price of $ 86.3 million.

We have made no repurchases since April 2015 and have approximately $ 43.7 million remaining under the repurchase program authorization as of December 31, 2025.

Inventories, at December 31, consist of the following:

4 unchanged sentences

Inventories $ 519.6 $ 539.0

For the year ended December 31, 2025, we recorded an inventory markdown of $ 8.4 million within Other operating expenses - net related to inventory at Hawesville that was sold during the first quarter of 2026 at a price below its carrying value.

Property, Plant and Equipment

20 unchanged sentences

Unrealized loss on financial instruments ( 0.3 ) ( 0.3 )

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

4 unchanged sentences

$ ( 95.6 ) $ 1.6 $ ( 94.0 )

Other comprehensive income (loss) before reclassifications ( 5.9 ) — ( 5.9 )

Net amount reclassified to net income (loss) ( 5.7 ) ( 0.1 ) ( 5.8 )

Other comprehensive loss before reclassifications

( 10.1 ) — ( 10.1 )

Net amount reclassified to Net loss 6.3 ( 0.1 ) 6.2

Balance, December 31, 2023

( 99.4 ) 1.5 ( 97.9 )

Other comprehensive income (loss) before reclassifications ( 10.1 ) — ( 10.1 )

Net amount reclassified to net income (loss) 6.3 ( 0.1 ) 6.2

Other comprehensive loss before reclassifications

( 11.9 ) — ( 11.9 )

Net amount reclassified to Net income 6.7 ( 0.2 ) 6.5

Balance, December 31, 2024

( 104.6 ) 1.3 ( 103.3 )

Other comprehensive income (loss) before reclassifications ( 11.9 ) — ( 11.9 )

Net amount reclassified to net income (loss) 6.7 ( 0.2 ) 6.5

Other comprehensive income before reclassifications 42.0 — 42.0

Net amount reclassified to Net income 6.2 ( 0.1 ) 6.1

Balance, December 31, 2025

$ ( 56.4 ) $ 1.2 $ ( 55.2 )

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

29 unchanged sentences

Eligible participants will be able to withdraw from their health reimbursement accounts to fund their own retiree medical coverage.

On February 13, 2026, we terminated our labor agreement with United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union ("USW") for former employees at our Hawesville facility.

See "Participation in Multi-employer Pension Plans" below for additional information.

During 2017, the Company amended its non-union retiree medical and life insurance benefits to align the Company’s benefits with the market and achieve a uniform retiree medical benefit design across the Company’s U.S.

1 unchanged sentence

Additionally, effective January 1, 2019, Century no longer administers non-union retiree medical, prescription drug, dental, or vision benefits and instead makes fixed health reimbursement account contributions.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

7 unchanged sentences

Interest cost 14.0 20.1 4.2 4.0

Plan amendments — 1.1 — —

Actuarial (gain) loss 7.7 6.5 ( 37.5 ) 0.6

Medicare Part D — — 0.2 0.2

Acquisition — 28.6 — 0.8

Benefits paid ( 19.4 ) ( 22.6 ) ( 5.1 ) ( 5.7 )

2 unchanged sentences

Benefit obligation at end of year $ 347.4 $ 342.5 $ 38.9 $ 77.0

The decreases in both the defined benefit plans' and OPEB plans' benefit obligation were mainly driven by lower interest costs and actuarial gains in 2024, which were primarily attributable to the changes in the discount rates from fiscal year 2023 to 2024.

The increase in the defined benefit plans' benefit obligation was mainly driven by actuarial gains in 2025, which were primarily attributable to the changes in the discount rates from fiscal year 2024 to 2025.

The decrease in OPEB plans' benefit obligation was mainly driven by a change in the post-65-years-of-age participant insurance coverage for post-65-years-of-age participants from fiscal year 2024 to 2025.

2025 2024 2025 2024

9 unchanged sentences

Fair value of assets at end of year $ 288.7 $ 272.2 $ — $ —

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

9 unchanged sentences

Amounts recognized in accumulated other comprehensive loss (pre-tax):

Net loss $ 82.3 $ 82.1 $ 14.4 $ 14.8

Net loss (gain) $ 78.5 $ 88.1 $ ( 23.9 ) $ 14.7

Prior service cost (benefit) 1.4 1.6 — —

3 unchanged sentences

At December 31, 2024, the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the pension plans with accumulated benefit obligations in excess of plan assets were $ 342.5 million, $ 303.4 million and $ 272.2 million, respectively.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Components of net periodic benefit cost and other amounts recognized in other comprehensive income (loss):

7 unchanged sentences

Amortization of net loss 5.1 5.8 6.0 0.9 0.7 0.1

Net periodic benefit cost 8.9 9.4 ( 5.3 ) 4.8 4.1 3.1

Curtailment benefit (1)

— — — — — ( 8.9 )

Total benefit cost $ 8.9 $ 9.4 $ ( 5.3 ) $ 4.8 $ 4.1 $ ( 5.8 )

(1) During 2022, we re-measured certain other postretirement benefits triggered by the Hawesville smelter curtailment, leading to a non-cash OPEB curtailment benefit totaling $ 8.9 million for the year ended December 31, 2022.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Other changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss) (pre-tax):

Total net periodic benefit cost $ 7.0 $ 10.8 $ 9.4 $ 5.2 $ 4.9 $ 4.1

Other changes in Plan Assets and Benefit Obligations Recognized in Accumulated Other Comprehensive Income (Loss) (pre-tax):

Year Ended December 31,

1 unchanged sentence

Net (gain) loss $ ( 4.4 ) $ 18.4 $ ( 37.5 ) $ 0.6

Net loss (gain) transferred due to acquisition — ( 4.5 ) — ( 0.2 )

Prior service cost (benefit) — 1.2 — —

Amortization of net loss, including recognition due to settlement ( 5.1 ) ( 5.8 ) ( 0.9 ) ( 0.7 )

11 unchanged sentences

Rate of compensation increase without Jamaica 3.2 % 3.0 % 3.2 % 3.0 %

Rate of compensation increase Jamaica 7.0 % n/a 7.0 % n/a

Rate of compensation increase Jamaica 7.0 % 7.0 % 7.0 % 7.0 %

Measurement date 12/31/2025 12/31/2024 12/31/2025 12/31/2024

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Weighted average assumptions used to determine net periodic benefit cost for the years ended December 31:

5 unchanged sentences

Rate of compensation increase without Jamaica (2)

3.5 % 4 %/ 3.5 %

Rate of compensation increase Jamaica 9.0 % n/a n/a 8.0 % n/a n/a

Rate of compensation increase Jamaica 7.0 % 9.0 % n/a 7.0 % 8.0 % n/a

Expected return on plan assets (3)

2 unchanged sentences

(2) For 2025, the rate of compensation increase is 3.2 %.

For 2023, the rate of compensation increase was 4 % per year for the first year and 3.5 % per year thereafter.

For 2024, the rate of compensation increase was 3.5 %.

For 2023, the rate of compensation increase was 4 % per year for the first year and 3.5 % per year thereafter.

(3) The rate for each of our defined benefit plans was selected by taking into account our expected asset mix and is based on historical performance as well as expected future rates of return on plan assets.

For measurement purposes, medical cost inflation for location other than Jamaica is initially estimated to be 8.5 %, and 7.5 % for pre- and post-65 participants, respectively, declining to 4.5 % over ten years and continuing thereafter.

For Jamaica, it is initially estimated to be 8.0 % for both pre and post 65 participants and for the next two years.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

For measure ment purposes, medical cost inflation for locations other than Jamaica is initially estimated to be 8.5 % for both pre- and post-65-years-of-age participants, declining to 4.5 % over ten years and continuing thereafter.

For Jamaica, it is initially estimated to be 8.0 % for both pre- and post-65-years-of-age participants and for the next two years.

Benefit Plan Assets

11 unchanged sentences

Investment objectives for each asset class are included below.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Asset Allocation Policy

2 unchanged sentences

Pension Plan Asset Allocation

2024 Target December 31, 2024 December 31, 2023

December 31, 2025 December 31, 2024

Return seeking assets:

15 unchanged sentences

fixed income market through the use of portfolio strategies targeting treasury bond exposures.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

• Hedge the interest rate risk of the pension obligation by investing in securities that target a similar duration to the pension obligation cash flows.

12 unchanged sentences

Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and the placement within the fair value hierarchy levels.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

As more fully described within Note 7.

5 unchanged sentences

• Level 3 Inputs – unobservable inputs for the asset or liability.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The following summarizes the Company’s Pension Plans' assets fair value by asset category:

28 unchanged sentences

Expected OPEB benefits payments 3.6

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

10 unchanged sentences

Participation in Multi-employer Pension Plans

The union-represented employees at Hawesville are part of a United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union ("USWA") sponsored multi-employer plan.

Our contributions to the plan are determined at a fixed rate per hour worked.

Currently, we do not have any plans to withdraw from or curtail participation in this plan.

The risks of participating in a multi-employer plan are different from single employer plans in the following respects:

• Assets contributed to the multi-employer plan by one employer may be used to provide benefits to employees of other participating employers.

• Assets contributed to the multiemployer plan by one employer may be used to provide benefits to employees of other participating employers.

• If a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers.

2 unchanged sentences

Fund Steelworkers Pension Trust

EIN / PN 23-6648508 / 499

23-6648508 / 499

Pension Protection Act Zone Status 2024 (2)

8 unchanged sentences

March 31, 2026

(1) The "EIN/Pension Plan Number" column provides the Employee Identification Number (EIN) and the three-digit plan number, if applicable.

(2) The most recent Pension Protection Act zone status available in 2025 and 2024 is for the plan's year-end December 31, 2024 and December 31, 2023, respectively.

The zone status is based on information that Century received from the plan as well as publicly available information per the Department of Labor and is certified by the plan’s actuary.

Among other factors, plans in the green zone are at least 80 percent funded.

Among other factors, plans in the red zone are generally less than 65 percent funded, plans in the yellow zone are less than 80 percent funded, and plans in the green zone are at least 80 percent funded.

(3) The “Subject to Financial Improvement / Rehabilitation Plan” column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented.

The last column lists the expiration date(s) of the collective-bargaining agreement(s) to which the plans are subject.

On February 13, 2026, we terminated our labor agreement with USW for former employees at our Hawesville facility.

Century's contributions to the above plan is not 5% or more of the total contributions to the plan.

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

21 unchanged sentences

PSUs can be settled in cash or stock and vest based on the achievement of pre-determined performance metrics at the discretion of the Board.

Our PSU liability was approximately $ 7.1 million and $ 3.3 million as of December 31, 2024 and 2023, respectively.

Our PSU liability, a component of both Accrued other current liabilities Other liabilities on the Consolidated Balance Sheets, was approximately $ 11.8 million and $ 7.1 million as of December 31, 2025 and 2024, respectively.

Both the PSUs and RSUs vest, in their entirety, after three years .

Service-based share awards Number

Service-based share awards Number Weighted-Average Grant Date Fair Value

Outstanding at January 1, 2025

1,404,895 $ 9.79

Granted 415,565 19.47

2 unchanged sentences

Outstanding at December 31, 2025

Performance-based share awards Number

1,144,774 13.24

Performance-based share awards Number Weighted-Average Grant Date Fair Value

Outstanding at January 1, 2025

774,475 $ 8.96

Granted 590,391 12.91

Vested ( 711,414 ) 7.89

Forfeited ( 92,045 ) 11.14

Outstanding at December 31, 2025

561,407 14.00

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Year ended December 31,

2 unchanged sentences

Fair Value Measurement of Share-Based Compensation Awards.

We estimate the fair value of each stock option award using the Black-Scholes model on the date of grant.

Our last grant of stock options, awarded in 2009, expired in May 2019.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

have not granted any stock options since 2009.

For our service-based awards, fair value is equal to the closing stock price on the date of grant.

4 unchanged sentences

2025 2024 2023

Share-based compensation (benefit) expense reported:

Performance-based share (benefit) expense $ 9.3 $ 2.0 $ ( 5.0 )

Share-based compensation expense reported:

Performance-based share expense $ 32.6 $ 9.3 $ 2.0

Service-based share expense 14.4 6.1 4.6

Total share-based compensation (benefit) expense before income tax 15.4 6.6 ( 0.6 )

Total share-based compensation expense before income tax 47.0 15.4 6.6

Income tax — — —

Total share-based compensation (benefit) expense, net of income tax $ 15.4 $ 6.6 $ ( 0.6 )

Total share-based compensation expense, net of income tax $ 47.0 $ 15.4 $ 6.6

No share-based compensation cost was capitalized during these periods and there were no significant modifications of any share-based awards in 2025, 2024 and 2023.

2 unchanged sentences

Earnings Per Share

Basic EPS amounts are calculated by dividing net income (loss) allocated to common stockholders by the weighted average number of common shares outstanding.

Diluted EPS amounts assume the issuance of common stock for all potentially dilutive common shares outstanding.

The following table shows the basic and diluted earnings (loss) per share for 2024, 2023, and 2022:

The following table shows the basic and diluted EPS for 2025, 2024, and 2023:

For the year ended December 31, 2025

5 unchanged sentences

Share-based compensation — 1.1

Convertible senior notes 2.7 4.6

Net income allocated to common stockholders

$ 40.0 95.3 $ 0.42

For the year ended December 31, 2023

Net Loss Shares

(in millions)

Net loss attributable to Century stockholders $ ( 43.1 )

Amount allocated to common stockholders 100 %

Basic and Diluted EPS:

$ ( 43.1 ) 92.4 $ ( 0.47 )

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

1 unchanged sentence

For the year ended December 31, 2024

Net Income Shares

(in millions)

Net income attributable to Century stockholders $ 336.8

net income allocated to participating securities 17.9

Net income allocated to common stockholders $ 318.9 92.8 $ 3.44

Effect of dilutive securities:

Share-based compensation — 1.0

Convertible senior notes 2.7 4.6

Net income allocated to common stockholders $ 321.6 98.4 $ 3.27

For the year ended December 31, 2023

Net Loss Shares

5 unchanged sentences

Securities excluded from the calculation of diluted EPS (in millions) (1) :

2025 2024 2023

Share-based compensation

2 unchanged sentences

(1) In periods when we report a net loss, all share-based compensation awards, convertible preferred shares and convertible senior notes are excluded from the calculation of diluted weighted average shares outstanding because of their anti-dilutive effect on earnings (loss) per share.

In 2025, the Company adopted ASU 2023-09, Income Taxes (Topic 740):

Improvements to Income Tax Disclosures, on a prospective basis.

This guidance requires disaggregated information about the effective tax rate reconciliation, additional disaggregated data on income taxes paid by jurisdiction, and certain other amendments to improve the effectiveness of income tax disclosures.

The adoption did not impact the Company’s consolidated financial position, results of operations, or cash flows but enhanced the income tax footnote disclosures for the year ended December 31, 2025.

The components of pre-tax book income (loss) consist of the following:

4 unchanged sentences

Total $ 2.7 $ 309.8 $ ( 71.1 )

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Significant components of income tax expense consist of the following:

10 unchanged sentences

Total income tax (benefit) expense $ ( 13.1 ) $ 3.2 $ ( 14.6 )

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

3 unchanged sentences

Year Ended December 31,

2024 2023 2022

Statutory U.S.

federal income tax rate $ 0.6 21.0 %

State income taxes, net of related federal income tax benefit (1)

Foreign tax effects

Valuation allowance ( 4.5 ) ( 165.0 )

Net operating loss expiration and remeasurement 4.5 163.8

Nondeductible interest 8.5 314.0

Nondeductible items 2.4 88.5

Fixed asset remeasurement 0.6 23.7

Other 1.0 35.7

Nontaxable items ( 2.4 ) ( 88.5 )

Other ( 0.3 ) ( 12.0 )

Minority interest 5.5 200.7

Valuation allowance 5.2 189.9

Nondeductible items 3.6 131.0

Federal statutory rate difference between Jamaica and the United States ( 1.1 ) ( 41.5 )

Effect of cross border tax laws ( 0.1 ) ( 4.5 )

Effect of changes in tax laws or rates enacted in the period — —

Changes in valuation allowances ( 11.7 ) ( 429.9 )

Nontaxable or nondeductible Items

Nontaxable advanced manufacturing production credit income ( 18.6 ) ( 683.5 )

Executive compensation 6.6 242.4

Stock compensation excess tax benefits ( 4.3 ) ( 156.5 )

Nontaxable interest ( 8.8 ) ( 322.8 )

Changes in unrecognized tax benefits 0.1 2.7

Other adjustments ( 0.2 ) ( 2.4 )

Effective income tax rates $ ( 13.1 ) ( 482.7 ) %

(1) State taxes in Tennessee and Kentucky comprise the majority (greater than 50 percent) of the tax effect in this category.

The effective tax rate for the year ending December 31, 2025 was ( 482.7 )% compared to the statutory US tax rate of 21%.

This lower effective rate is primarily due to the non-taxable benefit of the Advanced Manufacturing Production Credit under Section 45X, which is discussed below and favorable changes in the current year regarding our US valuation allowance.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Year Ended December 31,

Federal Statutory Rate 21.0 % 21.0 %

3 unchanged sentences

Foreign earnings taxed at different rates than U.S.

— 2.0 ( 0.8 )

Valuation allowance ( 11.6 ) 3.4

7 unchanged sentences

Effective tax rate 1.0 % 20.5 %

The effective tax rate for the year ending December 31, 2024 was 1.0 % compared to the statutory US tax rate of 21%.

This lower effective rate is primarily due to the bargain purchase gain recognized for US GAAP purposes but not for US tax purposes, as well as the non-taxable benefit of the Advanced Manufacturing Credit under Section 45X, which is discussed below.

In August 2022, the IRA became law.

The IRA provides several tax incentives to promote clean energy and the production of critical minerals in the U.S., including a refundable tax credit, pursuant to Section 45X of the Internal Revenue Code.

Tax credits, such as refundable credits whose realization does not depend on the entity’s generation of taxable income like the refundable tax credit provided by the IRA are not considered an element of income tax accounting under ASC 740.

After considering US GAAP, the Company has concluded it is appropriate to apply IAS 20, Accounting for Government Grants and Disclosure of Government Assistance , to account for the refundable tax credit as an income grant.

Section 45X of the IRA contains a production tax credit equal to 10% of certain eligible production costs, including, without limitation, labor, energy, depreciation and amortization and overhead expenses.

On December 14, 2023, the U.S.

Department of the Treasury and the Internal Revenue Service released proposed rules to provide guidance on the production tax credit requirements under Internal Revenue Code Section 45X (the “Proposed Regulations”).

The following table presents the amounts paid for income taxes, net of refunds:

Year Ended December 31, 2025

Netherlands 2.0

Section 45X of the Inflation Reduction Act of 2022 ("IRA") contains a production tax credit equal to 10% of certain eligible production costs, including, without limitation, labor, energy, depreciation and amortization and overhead expenses.

On October 24, 2024, the U.S.

Department of the Treasury and the Internal Revenue Service released final regulations regarding the advanced manufacturing production credit established by the Inflation Reduction Act of 2022 to incentivize the production of eligible components within the United States (the “Final Regulations”).

The Final Regulations provide guidance on rules that taxpayers must satisfy to qualify for the Section 45X tax credit.

One of the most significant changes from the Proposed Regulations is that the final regulations allow certain direct and indirect material costs to be included in the section 45X credit computation for the production of electrode active materials and critical minerals.

Notably, with respect to all of the comments related to the definition of aluminum, the Treasury Department and the IRS have determined that additional consideration is necessary prior to finalizing proposed § 1.45X–4(b)(1), which the Treasury Department and the IRS intend to do at a later date.

For that reason, § 1.45X–4(b)(1) is reserved in these Final Regulations.

Department of the Treasury and the Internal Revenue Service issued final regulations on the production tax credit requirements under Internal Revenue Code Section 45X (the "IRA Regulations").

The IRA Regulations provide guidance on rules that taxpayers must satisfy to qualify for the IRA Section 45X tax credit.

For the year ended December 31, 2025 and December 31, 2024, we recognized $ 89.1 million and $ 89.7 million as a reduction in Cost of goods sold, and $ 3.8 million and $ 2.9 million as a reduction in selling, general and administrative expenses, respectively, within the Consolidated Statements of Operations.

As of December 31, 2024 and December 31, 2023, the Company recognized a current manufacturing credit receivable of $ 81.5 million and $ 59.3 million, respectively.

As of December 31, 2024, the Company recognized a non-current manufacturing credit receivable of $ 70.4 million.

There was no non-current manufacturing credit receivable recognized as of December 31, 2023 within the Consolidated Balance Sheets.

The Company’s accounting policy with respect to releasing income tax effects from accumulated other comprehensive income is to apply a security by security approach whereby the tax effects are measured based on the change in the unrealized

CENTURY ALUMINUM COMPANY

In July 2025, the One Big Beautiful Bill Act (the "Act") became law.

The Act removed the exemption for critical minerals related to the phase out of the advanced manufacturing production tax credit under Internal Revenue Code Section 45X of the Inflation Reduction Act of 2022 and final regulations issued in October of 2024.

Under the Act, beginning in 2031, the amount of the tax credit will be reduced by 25% each year and reduced to 0% in 2034.

Additionally, the Act made changes to, but not limited to, permanently extending bonus depreciation that permits full expensing of qualified property, and changes to limitations on the deductibility of interest expense.

The Act did not have a material impact on our financial results for the year ending December 31, 2025.

We will continue to evaluate the effects of the Act on our results as further guidance is issued.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

gains or losses reflected in other comprehensive loss.

The significant components of our deferred tax assets and liabilities as of December 31 are as follows:

4 unchanged sentences

Derivative and hedging contracts 11.2 0.1

Fixed asset tax over book basis — 9.2

Other 28.6 29.4

4 unchanged sentences

Fixed asset book over tax basis ( 119.3 ) ( 115.9 )

Derivatives — —

Foreign basis differences 0.1 0.6

14 unchanged sentences

Beginning balance, valuation allowance $ 504.4 $ 537.6 $ 487.9

Remeasurement of deferred tax assets — — —

Release of valuation allowance — — —

Expiration of net operating losses ( 5.2 ) ( 6.1 ) ( 7.2 )

1 unchanged sentence

Ending balance, valuation allowance $ 471.0 $ 504.4 $ 537.6

CENTURY ALUMINUM COMPANY

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

6 unchanged sentences

(2) US state NOLs begin to expire in 2027.

(3) NOLs in Iceland expire between 2025 and 2026.

(3) NOLs in Iceland expire in 2026 and 2035.

(4) NOLs in Jamaica do not expire.

9 unchanged sentences

As of December 31, 2025, the Company’s gross unrecognized tax benefits totaled $ 3.6 million.

After considering the deferred tax accounting impact, it is expected that about $ 1.4 million of the total as of December 31, 2024 would favorably affect the effective tax rate if resolved in the Company’s favor.

Included in the above balances are tax positions relating to temporary differences where there is uncertainty about the timing of tax return inclusion, but not that the amounts will ultimately be tax deductible.

Because of the impact of deferred tax accounting, other than interest and penalties, the timing would not impact the annual effective tax rate but could accelerate the payment of cash to the taxing authority to an earlier period.

We do not expect a significant change in the balance of unrecognized tax benefits within the next twelve months.

It is our policy to recognize potential accrued interest and penalties related to unrecognized tax benefits in income tax expense.

The Company considers the undistributed earnings of its foreign subsidiaries and joint ventures to be permanently reinvested and has not provided for U.S.

federal income taxes on these unremitted earnings.

No deferred tax liability has been recorded for the related outside basis differences in these entities.

Determination of the amount of any unrecognized deferred tax liability on this outside basis difference is not practicable as such determination involves material uncertainties about the potential extent and timing of any reversals.

Century and its subsidiaries file income tax returns in the U.S.

6 unchanged sentences

The earliest statutory period open is beginning in 2020.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Commitments and Contingencies

1 unchanged sentence

While the results of such matters and claims cannot be predicted with certainty, we believe that the ultimate outcome of any such matters and claims will not have a material adverse impact on our financial condition, results of operations or liquidity.

However, because of the nature and inherent uncertainties of litigation and estimating liabilities, should

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

the resolution or outcome of these actions be unfavorable, our business, financial condition, results of operations and liquidity could be materially and adversely affected.

However, because of the nature and inherent uncertainties of litigation and estimating liabilities, should the resolution or outcome of these actions be unfavorable, our business, financial condition, results of operations and liquidity could be materially and adversely affected.

In evaluating whether to accrue for losses associated with legal or environmental contingencies, it is our policy to take into consideration factors such as the facts and circumstances asserted, our historical experience with contingencies of a similar nature, the likelihood of our prevailing and the severity of any potential loss.

9 unchanged sentences

CAWV has agreed to pay the remaining amounts under the settlement agreement in annual increments of $ 2.0 million for nine years .

As of December 31, 2024, $ 2.0 million was recorded in other current liabilities and $ 1.6 million was recorded in other liabilities.

As of December 31, 2025, $ 1.9 million was recorded in other current liabilities, representing the current accrual of the final payment.

PBGC Settlement

4 unchanged sentences

On October 1, 2021, we amended the PBGC Settlement Agreement (the "Amended PBGC Settlement Agreement") such that we removed the deferral mechanism and agreed to contribute approximately $ 2.4 million per year to our defined benefit pension plans for a total of approximately $ 9.6 million, over four years beginning o n November 30, 2022 and ending on November 30 , 2025, subject to acceleration if certain terms and conditions are met in such amendment.

As of December 31, 2024, we have made contributions of $ 7.2 million related to the Amended PBGC Settlement Agreement.

Power Commitments and Contingencies

Hawesville has a power supply arrangement with Kenergy and Century Marketer, LLC (“Century Marketer"), Century's wholly-owned subsidiary that acts as a MISO market participant.

Under this arrangement, Hawesville gets access to power at Midcontinent Independent System Operator ("MISO") pricing plus transmission and other costs.

As the MISO Market Participant, Century Marketer purchases power from MISO for resale to Kenergy, which then resells the power to Hawesville.

Century Marketer's power supply arrangement with Kenergy has an effective term through May 31, 2028, with automatic one-year extensions unless either party provides one-year notice of termination prior to the May 31 anniversary date.

Similarly, Kenergy's power supply contract with Hawesville has a term through December 31, 2026, with automatic one-year extensions unless either party provides one-year notice of termination prior to the December 31 anniversary date.

CENTURY ALUMINUM COMPANY

As of December 31, 2025, we have made all contributions under the Amended PBGC Settlement Agreement.

Sebree has a power supply arrangement with Kenergy and Century Marketer LLC (“Century Marketer"), Century's wholly-owned subsidiary that acts as a Midcontinent Independent System Operator ("MISO") market participant.

Under this arrangement, Sebree gets access to power at MISO pricing plus transmission and other costs.

As the MISO Market Participant, Century Marketer purchases power from MISO for resale to Kenergy, which then resells the power to Sebree.

Century Marketer's power supply arrangement with Kenergy has an effective term through May 31, 2028, with automatic one-year

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Sebree has a power supply arrangement with Kenergy and Century Marketer.

Under this arrangement, Sebree gets access to power at Midcontinent Independent System Operator ("MISO") pricing plus transmission and other costs.

As the MISO Market Participant, Century Marketer purchases power from MISO for resale to Kenergy, which then resells the power to Sebree.

Century Aluminum of South Carolina ("CASC") has a power supply agreement with Santee Cooper that has an effective term through December 2026.

extensions unless either party provides one-year notice of termination prior to the May 31 anniversary date.

Similarly, Kenergy's power supply contract with Sebree has a term through December 31, 2026, with automatic one-year extensions unless either party provides one-year notice of termination prior to the December 31 anniversary date.

Century Aluminum of South Carolina, Inc.

("CASC") has a power supply agreement with South Carolina Public Service Authority (“Santee Cooper”) that has an effective term through December 2031.

Under this power supply agreement, 100 % of Mt.

9 unchanged sentences

Approximately 84 % of Grundartangi’s work force is represented by five labor unions, governed by a labor agreement that establishes wages and work rules for covered employees.

This agreement was effective Through December 31, 2024.

Grundartangi is currently in the process of negotiating a new contract.

Until a new contract is reached, employees will continue to operate under the current agreement.

This agreement is effective through December 31, 2029.

100 % of Vlissingen’s workforce is represented by the Federation for the Metal and Electrical Industry ("FME"), a Netherlands' employers' organization for companies in the metal, electronics, electrical engineering and plastic sectors.

2 unchanged sentences

Approximately 36 % of our U.S.

based work force is represented by USW through separately negotiated labor agreements for each facility.

The labor agreement for Hawesville employees is effective Through April 1, 2026.

Upon announcement of the curtailment, Hawesville and the USW local union entered into effects bargaining.

An agreement was reached on July 19, 2022, covering the curtailment period.

Century Sebree's labor agreement with USW for its employees is effective through October 28, 2028.

based work force is represented by the Allied Industrial and Service Workers International Union ("USW") through separately negotiated labor agreements for each facility.

The labor agreement for Hawesville employees was effective through April 1, 2026, but was terminated early on February 13, 2026.

Holly employees are not represented by a labor union.

Century Sebree's labor agreement with the USW for its employees is effective through October 28, 2028.

Approximately 62 % of Jamalco's work force is represented by the Union of Technical, Administrative, and Supervisory Personnel ("UTASP") through separately labor agreements for hourly and salaried employee groups.

4 unchanged sentences

We have a contingent obligation in connection with the “unwind” of a contractual arrangement between CAKY, Big Rivers Electric Corporation ("Big Rivers") and a third party and the execution of a long-term cost-based power contract with Kenergy, a member of a cooperative of Big Rivers, in July 2009.

This contingent obligation consists of the aggregate payments

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

made to Big Rivers by the third party on CAKY’s behalf in excess of the agreed upon base amount under the long-term cost-based power contract with Kenergy.

This contingent obligation consists of the aggregate payments made to Big Rivers by the third party on CAKY’s behalf in excess of the agreed upon base amount under the long-term cost-based power contract with Kenergy.

As of December 31, 2025, the principal and accrued interest for the contingent obligation was $ 33.7 million , which was fully offset by a derivative asset.

2 unchanged sentences

Interest accrues at an annual rate equal to 10.94 %.

As of December 31, 2024, the LME forward market prices do not exceed the threshold for payment.

In addition, based on the current level of Hawesville's operations, including the curtailment, we believe that we will not be required to make payments on the contingent obligation during the term of the agreement, which expires in 2028.

As of December 31, 2025, the LME forward market prices exceed the threshold for payment.

In addition, based on the fact that we recently sold the Hawesville property, which is to be developed into a data center, we believe that we will not be required to make payments on the contingent

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

obligation during the term of the agreement, which expires in 2028.

There can be no assurance that circumstances will not change thus accelerating the timing of such payments.

6 unchanged sentences

Accretion expense 3.4 2.5

Acquired ARO liabilities (See Note 2) — 23.9

Acquired ARO liabilities — 21.9

Revisions in estimated cash flows ( 3.3 ) 10.8

4 unchanged sentences

Business Segments

Century Aluminum is a producer of primary aluminum, which trades as a global commodity, and owns a 55 % interest in an alumina refinery joint venture.

We are organized as a holding company with each of our operating primary aluminum smelters managed and operated as a separate facility reporting to our corporate headquarters.

Our three operating primary aluminum smelters and our bauxite and alumina refinery each meet the definition of an operating segment We evaluated the similar economic and other characteristics, including similar products, production processes, customers and distribution and have aggregated our four operating segments into one reportable segment.

In addition, all of our operating segments share several key economic factors inherent in their common products and production processes.

For example, all of our facilities' revenue is based on market pricing.

Our facilities have a similar customer base and utilize similar distribution methods to ship products.

In 2024, we determined that our fully curtailed Hawesville facility no longer met the definition of an operating segment.

Our chief executive officer is our chief operating decision maker (CODM) and evaluates performance based on Segment EBITDA (Earnings before interest, taxes, depreciation, and amortization).

Specifically, the CODM reviews Segment EBITDA to develop forecasting and evaluate overall profitability performance.

CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

A reconciliation of our consolidated assets to the total of primary aluminum segment assets and capital expenditures is provided below.

Segment assets (1)

2024 2023 2022

Aluminum $ 1,896.6 $ 1,808.1 $ 1,432.4

Corporate, unallocated 42.8 38.4 39.6

Total assets $ 1,939.4 $ 1,846.5 $ 1,472.0

Capital expenditures $ 82.3 $ 95.0 $ 86.3

(1) Segment assets include accounts receivable, due from affiliates, prepaid and other current assets, leases - right of use assets, inventory, intangible assets and property, plant and equipment, net;

the remaining assets are unallocated corporate assets.

Geographic information

Our net sales are attributed to geographic area based on the location of the selling operation.

Included in the consolidated financial statements are the following amounts related to geographic locations:

2024 2023 2022

United States $ 1,427.0 $ 1,358.6 $ 1,737.2

Iceland 793.3 826.8 1,040.1

Total Net sales

2,220.3 2,185.4 2,777.3

Long-lived assets:

United States $ 233.6 $ 219.1 $ 244.9

Iceland 526.4 529.4 491.0

Jamaica 255.2 275.8 —

Other 50.6 55.1 58.3

(1) Includes sales of primary aluminum, scrap aluminum and alumina, and purchased aluminum and alumina.

(2) Includes long-lived assets other than financial instruments and deferred taxes.

Major customer information

Revenues from one customer in 2024 and 2023 and two customers in 2022 exceeded 10 % of our net sales.

A loss of these customers could have a material adverse effect on our results of operations.

The net sales related to the customers is as follows:

Year Ended December 31,

2024 2023 2022

Glencore $ 1,312.1 $ 1,612.1 $ 1,671.1

Southwire — — 331.3

CENTURY ALUMINUM COMPANY

The Company is a producer of primary aluminum and alumina.

The Company has organized itself, including management personnel and systems, financial processes, operational execution, governance and risk oversight, regulatory compliance, and every other aspect of the Company’s operations, to assess and manage the business on a holistic basis, from mine to metal, which tracks the upstream manufacturing process for aluminum.

To better reflect this operational and organizational approach, and to further enhance the reporting of its financial and operating results, beginning with the quarter ended March 31, 2025, the Company’s Chief Executive Officer and Chief Operating Decision Maker ("CODM") regularly receives and reviews financial information at the consolidated level to evaluate business performance and make operating decisions.

The CODM uses the U.S.

GAAP measure of consolidated Net Income to develop forecasting, to evaluate the Company’s overall profitability and financial performance and to make key operating decisions, such as the allocation of resources.

Given the change described above, the Company has determined that neither its three smelters nor Jamalco’s mining and refining operations meet the definition of operating segments.

As a result, the Company has determined that the Company has only one operating and only one reportable segment, and it is managed on a consolidated basis.

In accordance with ASC 280-10-50-34, the corresponding information for earlier periods is recast in the tables below to conform with the updated presentation.

Segment assets are reported on our Consolidated Balance Sheets as Total assets.

Our Consolidated Statements of Cash Flows presents Depreciation, depletion and amortization expense and includes the measure of Capital expenditures.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The following table presents our segment information to reconcile to Segment EBITDA for the periods indicated and, because we only have one segment, our net income (loss) attributable to Century stockholders is identical to the information presented in the Consolidated Statements of Operations:

The following table presents information about the Company's single segment for the years ended December 31, .

Year Ended December 31,

3 unchanged sentences

( 2,256.7 ) ( 2,042.7 ) ( 2,099.7 )

IRA Credit - Cost of goods sold (2)

Asset impairment

IRA Credit (1),(3)

89.1 89.7 56.5

Other segment items (3)

Lower of cost or NRV inventory adjustment (1),(4)

( 8.6 ) 4.2 27.5

Segment EBITDA

Property and equipment expense (1),(5)

( 95.3 ) ( 99.5 ) ( 82.1 )

Depreciation, depletion, and amortization - Cost of goods sold ( 86.5 ) ( 80.7 ) ( 76.4 )

Selling, general and administrative expenses ( 79.9 ) ( 56.8 ) ( 44.3 )

Other operating expenses - net ( 18.4 ) ( 6.8 ) ( 15.8 )

Interest expense - nonaffiliates ( 41.9 ) ( 36.4 ) ( 33.7 )

Interest expense - affiliates ( 5.8 ) ( 6.7 ) ( 1.8 )

Interest expense ( 36.4 ) ( 33.7 ) ( 29.3 )

Interest income 9.2 2.1 2.0

Net gain (loss) on forward and derivative contracts - nonaffiliates 2.5 ( 62.4 ) 210.4

Net (loss) gain on forward and derivative contracts - nonaffiliates ( 94.7 ) 2.5 ( 62.4 )

Net gain (loss) on forward and derivative contracts - affiliates — ( 0.5 ) 0.6

Loss on early extinguishment of debt ( 7.7 ) — —

Bargain purchase gain — 245.9 —

( 9.7 ) 24.1 ( 29.1 )

Other expense - net ( 14.5 ) ( 5.5 ) ( 3.3 )

Income tax benefit (expense) 13.1 ( 3.2 ) 14.6

Equity in earnings (losses) of joint ventures — 0.1 ( 0.1 )

Net income (loss) $ 15.8 $ 306.7 $ ( 56.6 )

Net loss attributable to noncontrolling interests

Net income (loss) attributable to Century stockholders, as reported $ 336.8 $ ( 43.1 ) $ ( 14.1 )

(1) Includes raw materials, labor, energy, and other direct cost of goods sold.

(2) Advanced production credit related to Section 45X of the Inflation Reduction Act.

(3) Includes freight costs and FIFO inventory adjustment.

(4) Includes equity in losses or earnings from joint ventures and inventory revaluation to lower of cost or net realizable value.

As of December 31, 2024, we had an open position of 32,000 tonnes related to LME forward financial sales contracts to fix the forward LME aluminum price and an open position of 32,000 tonnes related to MWP forward financial sales contracts to fix the forward MWP price.

These contracts are expected to settle monthly through September 2026.

We also enter into financial contracts with various counterparties to offset fixed price sales arrangements with certain of our customers ("fixed for floating swaps") to remain exposed to the LME and MWP aluminum prices.

As of December 31, 2024, we had no open fixed for floating swaps.

We previously entered into forward contracts to hedge the risk of fluctuations associated with the Icelandic Krona (ISK) and Euro for contracts related to the construction of the Grundartangi casthouse and the Sebree casthouse project denominated in these currencies ("casthouse currency hedges").

As of December 31, 2024, we had no open casthouse currency hedges.

We previously entered into financial contracts to hedge a portion of our exposure at our operations to the NYMEX Henry Hub (“NYMEX Henry Hub natural gas price swaps”).

The natural gas volume is measured per million British Thermal Units ("MMBtu").

As of December 31, 2024, we had no open NYMEX Henry Hub natural gas price swaps.

We have entered into financial contracts to hedge a portion of our exposure at our operations to Heavy Fuel Oil (“HFO price swaps”).

The HFO volume is measured per barrel.

As of December 31, 2024, we had an open position of 295,000 barrels.

The HFO price swaps are expected to settle monthly through December 2025.

CENTURY ALUMINUM COMPANY

(1) A component of Cost of goods sold.

(2) Includes raw materials, labor, energy, freight costs, FIFO inventory adjustments and other direct cost of goods sold.

(3) Advanced production credit related to Section 45X of the IRA.

(4) Includes inventory revaluation to lower of cost or net realizable value and changes in inventory reserve.

(5) Represents the depreciation expenses and expenses related to leased assets that are directly related to the cost of goods sold.

Long-lived Assets

As of December 31,

2025 2024 2023

Long-lived assets:

United States $ 232.1 $ 233.6 $ 219.1

Iceland 506.5 526.4 529.4

Jamaica 449.5 435.3 458.1

Other 48.6 50.6 55.1

(1) Includes long-lived assets other than financial instruments and deferred taxes.

Major customer information

Revenues from Glencore in 2025, 2024 and 2023 exceeded 10 % of our net sales.

Related Party Transactions for additional information on sales to Glencore .

As of December 31, 2025, we had an open position of 48,400 tonnes related to LME forward financial sales contracts to fix the forward LME aluminum price.

These contracts are expected to settle monthly through June 2027.

We had an open position of 89,800 tonnes related to MWP forward financial sales contracts to fix the forward MWP price.

These contracts are expected

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

to settle monthly through December 2027.

As of December 31, 2025, we had no open fixed for floating swaps.

We have entered into financial contracts to hedge a portion of our Jamalco fuel cost exposure ("HFO price swaps").

The volume of heavy fuel oil ("HFO") consumed at Jamalco is measured per barrel and as of December 31, 2025, we had an open position of 225,000 barrels.

The HFO price swaps are expected to settle monthly through October 2026.

We have entered into financial contracts to fix a portion of our exposure to the Indiana Hub power market at our Sebree plant ("Indiana Hub power price swaps").

As of December 31, 2025, we had an open position of 884,712 MWh.

The Indiana Hub power price swaps are expected to settle monthly through September 2026.

The Indiana Hub power price swaps are expected to settle monthly through June 2027.

Our agreements with derivative counterparties contain certain provisions requiring collateral to be posted in the event the market value of our position exceeds the margin threshold limit of our master agreement with the counterparty.

As of December 31, 2024 and December 31, 2023, the Company had not recorded restricted cash as collateral related to open derivative contracts under the master arrangements with our counterparties.

As of December 31, 2025 and December 31, 2024, the Company had no recorded restricted cash as collateral related to open derivative contracts under the master arrangements with our counterparties.

The following table sets forth the Company's derivative assets and liabilities that were accounted for at fair value and not designated as cash flow hedges as of December 31, 2025 and 2024, respectively:

1 unchanged sentence

Commodity contracts (1)

Foreign exchange contracts (2)

Total $ 4.5 $ 2.9

Liability Fair Value

Commodity contracts (1)

Foreign exchange contracts (2)

Total $ 4.4 $ 7.9

(1) Commodity contracts reflect our outstanding LME and MWP forward financial sales contracts, fixed for floating swaps, HFO price swaps and Indiana Hub power price swaps.

At December 31, 2024, $ 0.0 million of Due to affiliates was related to commodity contract liabilities with Glencore.

At December 31, 2023, $ 6.4 million of Due to affiliates was related to commodity contract liabilities with Glencore.

At December 31, 2025 and December 31, 2024, there were no commodity contracts with Glencore.

(2) Foreign exchange contracts reflect our outstanding FX swaps and casthouse currency hedges.

2 unchanged sentences

2025 2024 2023

Net gain (loss) on forward and derivative contracts - nonaffiliates

Commodity contracts $ ( 94.7 ) $ 1.6 $ 62.9

Foreign exchange contracts — ( 0.1 ) ( 1.7 )

( 94.7 ) 1.5 61.2

Net gain (loss) on forward and derivative contracts - affiliates

Commodity contracts — 0.5 0.6

Foreign exchange contracts — — —

Total $ ( 94.7 ) $ 2.0 $ 61.8

(1) For the years ended December 31, 2024, 2023, and 2022, $( 0.5 ) million, $ 0.6 million, and $( 13.3 ) million of net gain (loss), respectively, was with Glencore.

Variable Interest Entity

The Company consolidates Jamalco, a bauxite mining and alumina refinery in Jamaica, under the variable interest entity ("VIE") model.

The Company's wholly-owned subsidiary, General Alumina Jamaica Limited, is the managing partner of the Jamalco joint venture.

Jamalco lacks sufficient equity investment at risk in accordance with relevant guidance.

Based on its purpose and design, Jamalco is expected to require additional subordinated financial support, such as those in the form of equity contributions or other forms of subordinated financing, which the Company expects would require parent guarantees.

To that end, the Company made an immediate equity contribution to Jamalco upon acquisition, and has provided subsequent financing of costs for Jamalco to perform its activities in the ordinary course of business.

Jamalco was designed in order to distribute operations risk related to the mining and alumina refining operations, as well as commodity price risk.

CENTURY ALUMINUM COMPANY

Based on its purpose

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

and design, Jamalco is expected to require additional subordinated financial support, such as those in the form of equity contributions or other forms of subordinated financing, which the Company expects would require parent guarantees.

The Company owns a 55 % ownership interest in Jamalco through its wholly-owned subsidiary, GAJL, which serves as the managing partner.

The Company is responsible for funding 55 % of Jamalco's operating costs and capital requirements and is not obligated to provide additional financial support beyond its equity interest.

Upon acquisition, the Company made an immediate equity contribution to Jamalco and has provided subsequent financing of costs for Jamalco to perform its activities in the ordinary course of business.

The Company obtains direct ownership of our 55 % share of Jamalco’s outputs and purchases the remaining 45 % of the output from the Government of Jamaica.

Through direct ownership and purchase, 100 % of Jamalco’s output is either retained and utilized in the Company’s business operations or sold by the Company.

The Company’s consolidated statement of cash flows reflects 100 % of cash flows related to the Jamalco operations.

The Company receives cash proceeds from the Government of Jamaica for its 45 % interest of the Jamalco operating costs and capital requirements.

Although our partner has certain participating rights over some decisions of the entity, the Company has power over the majority of key activities at Jamalco that significantly affect its economic performance over which the counterparty does not have such participating rights;

3 unchanged sentences

Accounts receivable - net 0.1 1.1

Inventories 116.6 109.8

Prepaid and other current assets 8.9 2.0

Total current assets 130.2 130.3

Property, plant and equipment - net 426.3 403.6

Other assets 12.0 24.1

TOTAL $ 568.5 $ 558.0

Accounts payable, trade $ 49.0 $ 39.1

Accrued compensation and benefits 11.7 9.5

Due to affiliates 17.3 49.6

Accrued and other current liabilities 8.2 9.7

Total current liabilities 86.2 107.9

Accrued benefits costs - less current portion 32.2 32.2

Other liabilities 62.1 66.7

Asset retirement obligations - less current portion 46.6 54.8

Total noncurrent liabilities 140.9 153.7

$ 227.1 $ 261.6

Restatement of Previously Issued Financial Statements

Subsequent to the issuance of our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, the Company identified an error in accounting in its historical financial statements related to the consolidation of its Jamalco joint venture

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

whereby the Company previously used the proportionate method of consolidation for certain of Jamalco's net assets versus the full consolidation method.

The Company has corrected the error in the Consolidated Financial Statements as of and for the periods ended December 31, 2024 and December 31, 2023 presented herein.

Revisions to the Company’s previously reported disclosures have been reflected in Note 1.

Summary of Signific a n t Accounting Policie s ;

Acquisition of Jamalco ;

Property, Plant and Equipment ; Note 13.

Pension and Other Postretirement Benefits ;

Asset Retirement Obligations ;

Business Segments ; and Note 21.

Variable Interest Entity .

A summary of the revisions to the Company’s previously reported financial statements is provided in this Note 22.

Restatement of Previously Issued Financial Statements and Note 23.

Revisions to Prior Period Quarterly Consolidated Financial Statements (unaudited) .

The effects of the corrections described above on the Company’s Consolidated Statements of Operations were as follows:

Year Ended December 31, 2024

As Previously Reported Restatement Impacts As Restated

Related parties $ 1,312.1 $ — $ 1,312.1

Other customers 908.2 — 908.2

Total net sales 2,220.3 — 2,220.3

Cost of goods sold 2,035.3 13.0 2,048.3

Gross profit 185.0 ( 13.0 ) 172.0

Selling, general and administrative expenses 56.8 — 56.8

Other operating expenses - net 6.8 — 6.8

Operating income 121.4 ( 13.0 ) 108.4

Interest expense - affiliates ( 6.7 ) — ( 6.7 )

Interest expenses - nonaffiliates ( 36.4 ) — ( 36.4 )

Interest income 2.1 — 2.1

Net gain on forward and derivative contracts - nonaffiliates 2.5 — 2.5

Net loss on forward and derivative contracts - affiliates ( 0.5 ) — ( 0.5 )

Bargain purchase gain 245.9 — 245.9

Other expense - net ( 4.5 ) ( 1.0 ) ( 5.5 )

Income before income taxes 323.8 ( 14.0 ) 309.8

Income tax expense ( 3.2 ) — ( 3.2 )

Income before equity in earnings of joint ventures 320.6 ( 14.0 ) 306.6

Equity in earnings of joint ventures 0.1 — 0.1

Net income 320.7 ( 14.0 ) 306.7

Net loss attributable to noncontrolling interests ( 16.1 ) ( 14.0 ) ( 30.1 )

Net income attributable to Century stockholders 336.8 — 336.8

Net income allocated to participating securities 17.9 — 17.9

Net income allocated to common stockholders $ 318.9 $ — $ 318.9

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Year Ended December 31, 2023

As Previously Reported Restatement Impacts As Restated

Related parties $ 1,612.1 $ — $ 1,612.1

Other customers 573.3 — 573.3

Total net sales 2,185.4 — 2,185.4

Cost of goods sold 2,093.5 4.3 2,097.8

Gross profit 91.9 ( 4.3 ) 87.6

Selling, general and administrative expenses 44.3 — 44.3

Other operating expenses - net 15.8 — 15.8

Operating income 31.8 ( 4.3 ) 27.5

Interest expense - affiliates ( 1.8 ) — ( 1.8 )

Interest expenses - nonaffiliates ( 33.7 ) — ( 33.7 )

Interest income 2.0 — 2.0

Net loss on forward and derivative contracts - nonaffiliates ( 62.4 ) — ( 62.4 )

Net gain on forward and derivative contracts - affiliates 0.6 — 0.6

Bargain purchase gain — — —

Other expense - net ( 3.3 ) — ( 3.3 )

Loss before income taxes ( 66.8 ) ( 4.3 ) ( 71.1 )

Income tax benefit 14.6 — 14.6

Loss before equity in earnings of joint ventures ( 52.2 ) ( 4.3 ) ( 56.5 )

Equity in losses of joint ventures ( 0.1 ) — ( 0.1 )

Net loss ( 52.3 ) ( 4.3 ) ( 56.6 )

Net loss attributable to noncontrolling interests ( 9.2 ) ( 4.3 ) ( 13.5 )

Net loss attributable to Century stockholders ( 43.1 ) — ( 43.1 )

Net income allocated to participating securities — — —

Net loss allocated to common stockholders $ ( 43.1 ) $ — $ ( 43.1 )

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The effects of the corrections described above on the Company's Consolidated Statements of Comprehensive Income (Loss) were as follows:

Year Ended December 31, 2024

As Previously Reported Restatement Impacts As Restated

Comprehensive income:

Net income $ 320.7 $ ( 14.0 ) $ 306.7

Other comprehensive loss before income tax effect:

Net loss on foreign currency cash flow hedges reclassified as income ( 0.2 ) — ( 0.2 )

Defined benefit plans and other postretirement benefits:

Net loss arising during the period ( 11.9 ) ( 1.2 ) ( 13.1 )

Amortization of prior service benefit during the period 0.2 — 0.2

Amortization of net loss during the period 6.5 — 6.5

Other comprehensive loss before income tax effect:

( 5.4 ) ( 1.2 ) ( 6.6 )

Income tax effect — — —

Other comprehensive loss ( 5.4 ) ( 1.2 ) ( 6.6 )

Comprehensive income 315.3 ( 15.2 ) 300.1

Comprehensive loss attributable to noncontrolling interests ( 16.1 ) ( 15.2 ) ( 31.3 )

Comprehensive income attributable to Century Stockholders $ 331.4 $ — $ 331.4

Year Ended December 31, 2023

As Previously Reported Restatement Impacts As Restated

Comprehensive loss:

Net loss $ ( 52.3 ) $ ( 4.3 ) $ ( 56.6 )

Other comprehensive loss before income tax effect:

Net loss on foreign currency cash flow hedges reclassified as income ( 0.1 ) — ( 0.1 )

Defined benefit plans and other postretirement benefits:

Net loss arising during the period ( 10.1 ) ( 9.1 ) ( 19.2 )

Amortization of prior service benefit during the period 0.1 — 0.1

Amortization of net loss during the period 6.2 — 6.2

Other comprehensive loss before income tax effect:

( 3.9 ) ( 9.1 ) ( 13.0 )

Income tax effect — — —

Other comprehensive loss ( 3.9 ) ( 9.1 ) ( 13.0 )

Comprehensive loss ( 56.2 ) ( 13.4 ) ( 69.6 )

Comprehensive loss attributable to noncontrolling interests ( 9.2 ) ( 13.4 ) ( 22.6 )

Comprehensive loss attributable to Century Stockholders $ ( 47.0 ) $ — $ ( 47.0 )

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The effects of the corrections described above on the Company's Consolidated Balance Sheets were as follows:

Year Ended December 31, 2024

As Previously Reported Restatement Impacts As Restated

Cash and cash equivalents $ 32.9 $ — $ 32.9

Restricted cash 2.8 — 2.8

Accounts receivable - net 75.8 — 75.8

Non-trade receivables 13.2 8.1 21.3

Due from affiliates 25.1 — 25.1

Manufacturing credit receivable 81.5 — 81.5

Inventories 539.0 — 539.0

Derivative assets 4.2 — 4.2

Prepaid and other current assets 28.3 — 28.3

1 unchanged sentence

Property, plant and equipment - net 978.3 171.5 1,149.8

Manufacturing credit receivable - less current portion 70.4 — 70.4

Other assets 87.9 1.0 88.9

TOTAL $ 1,939.4 $ 180.6 $ 2,120.0

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accounts payable, trade $ 187.3 $ — $ 187.3

2 unchanged sentences

Accrued and other current liabilities 42.0 2.6 44.6

Derivative liabilities 4.4 — 4.4

Current maturities of long-term debt 70.9 — 70.9

Total current liabilities 463.7 3.6 467.3

Long-term debt 447.3 — 447.3

Long-term debt due to affiliates 10.0 — 10.0

Accrued benefits costs - less current portion 130.4 14.5 144.9

Other liabilities 92.6 — 92.6

Deferred taxes 71.2 — 71.2

Asset retirement obligations - less current portion 61.5 19.8 81.3

Total noncurrent liabilities 813.0 34.3 847.3

COMMITMENTS AND CONTINGENCIES

SHAREHOLDERS’ EQUITY:

Preferred stock — — —

Common stock 1.0 — 1.0

Additional paid-in capital 2,550.2 — 2,550.2

Treasury stock, at cost ( 86.3 ) — ( 86.3 )

Accumulated other comprehensive loss ( 103.3 ) — ( 103.3 )

Accumulated deficit ( 1,667.2 ) — ( 1,667.2 )

Total Century shareholders’ equity 694.4 — 694.4

Noncontrolling interests ( 31.7 ) 142.7 111.0

Total equity 662.7 142.7 805.4

TOTAL $ 1,939.4 $ 180.6 $ 2,120.0

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Year Ended December 31, 2023

As Previously Reported Restatement Impacts As Restated

Cash and cash equivalents $ 88.8 $ — $ 88.8

Restricted cash 1.5 — 1.5

Accounts receivable - net 53.7 — 53.7

Non-trade receivables 36.2 — 36.2

Due from affiliates 20.2 — 20.2

Manufacturing credit receivable 59.3 — 59.3

Inventories 477.0 — 477.0

Derivative assets 2.9 — 2.9

Prepaid and other current assets 27.5 — 27.5

Total current assets 767.1 767.1 — 767.1

Property, plant and equipment - net 1,004.2 180.0 1,184.2

Manufacturing credit receivable - less current portion — — —

Other assets 75.2 2.3 77.5

TOTAL $ 1,846.5 $ 182.3 $ 2,028.8

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accounts payable, trade $ 249.5 $ — $ 249.5

Accrued compensation and benefits 38.1 0.6 38.7

Due to affiliates 101.4 — 101.4

Accrued and other current liabilities 50.9 — 50.9

Derivative liabilities 1.4 — 1.4

Deferred credit - preliminary bargain purchase gain 273.4 — 273.4

Current debt due to affiliates 10.0 — 10.0

Current maturities of long-term debt 38.3 — 38.3

Total current liabilities 763.0 0.6 763.6

Long-term debt 430.9 — 430.9

Accrued benefits costs - less current portion 120.3 9.1 129.4

Other liabilities 66.3 — 66.3

Deferred taxes 72.4 — 72.4

Asset retirement obligations - less current portion 49.5 13.5 63.0

Total noncurrent liabilities 739.4 22.6 762.0

COMMITMENTS AND CONTINGENCIES

SHAREHOLDERS’ EQUITY:

Preferred stock — — —

Common stock 1.0 — 1.0

Additional paid-in capital 2,542.9 — 2,542.9

Treasury stock, at cost ( 86.3 ) — ( 86.3 )

Accumulated other comprehensive loss ( 97.9 ) — ( 97.9 )

Accumulated deficit ( 2,004.1 ) — ( 2,004.1 )

Total Century shareholders’ equity 355.6 — 355.6

Noncontrolling interests ( 11.5 ) 159.1 147.6

Total equity 344.1 159.1 503.2

TOTAL $ 1,846.5 $ 182.3 $ 2,028.8

The effects of the corrections described above on the Company’s Consolidated Statements of Cash Flows were as follows:

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Consolidated Statements of Cash Flows

(in millions)

Year Ended December 31, 2024

As Previously Reported Restatement Impacts As Restated

CASH FLOWS FROM OPERATING ACTIVITIES:

Net income $ 320.7 $ ( 14.0 ) $ 306.7

Adjustments to reconcile net income to net cash used in operating activities:

Unrealized gain on derivative instruments ( 5.0 ) — ( 5.0 )

Depreciation, depletion and amortization 81.8 4.9 86.7

Change in deferred tax benefit ( 1.3 ) — ( 1.3 )

Gain on sale of assets ( 2.3 ) — ( 2.3 )

Bargain purchase gain ( 245.9 ) — ( 245.9 )

Force majure settlement ( 12.3 ) — ( 12.3 )

Lower of cost or NRV inventory adjustment 2.3 — 2.3

Other non-cash items - net 9.1 17.9 27.0

Change in operating assets and liabilities, net of acquisition:

Accounts receivable - net ( 18.3 ) — ( 18.3 )

Non-trade receivables 31.5 ( 8.2 ) 23.3

Manufacturing credit receivable ( 92.6 ) — ( 92.6 )

Due from affiliates ( 4.9 ) — ( 4.9 )

Inventories ( 64.3 ) — ( 64.3 )

Prepaid and other current assets 1.0 — 1.0

Accounts payable, trade ( 50.6 ) — ( 50.6 )

Due to affiliates 26.1 — 26.1

Accrued and other current liabilities ( 1.2 ) 5.2 4.0

Ravenswood retiree legal settlement ( 2.0 ) — ( 2.0 )

PBGC Settlement ( 0.3 ) — ( 0.3 )

Other - net 3.9 ( 5.8 ) ( 1.9 )

Net cash used in operating activities ( 24.6 ) — ( 24.6 )

CASH FLOWS FROM INVESTING ACTIVITIES:

Purchase of property, plant and equipment ( 82.3 ) — ( 82.3 )

Proceeds from co-tenancy assets at Jamalco JV 12.7 ( 12.7 ) —

Proceeds from sale of property, plant and equipment 2.3 — 2.3

Net cash used in investing activities ( 67.3 ) ( 12.7 ) ( 80.0 )

CASH FLOWS FROM FINANCING ACTIVITIES:

Borrowing under revolving credit facilities 735.4 — 735.4

Repayments under revolving credit facilities ( 705.1 ) — ( 705.1 )

Borrowings under Grundartangi casthouse debt facility 25.0 — 25.0

Repayments on casthouse facility ( 6.8 ) — ( 6.8 )

Repayments under Iceland term facility ( 1.2 ) — ( 1.2 )

Contributions from JV partner — 12.7 12.7

Carbon credit repayments ( 10.0 ) — ( 10.0 )

Net cash provided by financing activities 37.3 12.7 50.0

CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH ( 54.6 ) — ( 54.6 )

Cash, cash equivalents and restricted cash, beginning of year 90.3 — 90.3

Cash, cash equivalents and restricted cash, end of year $ 35.7 $ — $ 35.7

Supplemental Cash Flow Information

Cash paid for:

Interest $ 36.0 $ — $ 36.0

Taxes, net of refunds $ 14.5 $ — $ 14.5

Non-cash investing activities:

Capital expenditures $ 12.3 $ — $ 12.3

Capitalized interest 3.4 — 3.4

Distribution of fixed assets to NCI 17.0 ( 17.0 ) —

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Year Ended December 31, 2023

As Previously Reported Restatement Impacts As Restated

CASH FLOWS FROM OPERATING ACTIVITIES:

Net loss $ ( 52.3 ) $ ( 4.3 ) $ ( 56.6 )

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

Unrealized loss on derivative instruments 87.1 — 87.1

Depreciation, depletion and amortization 74.7 4.3 79.0

Change in deferred tax benefit ( 30.8 ) — ( 30.8 )

Other non-cash items - net 3.4 — 3.4

Change in operating assets and liabilities, net of acquisition:

Accounts receivable - net 36.9 — 36.9

Non-trade receivables 4.1 — 4.1

Manufacturing credit receivable ( 59.3 ) — ( 59.3 )

Due from affiliates ( 15.5 ) — ( 15.5 )

Inventories 25.8 — 25.8

Prepaid and other current assets 2.9 — 2.9

Accounts payable, trade ( 19.4 ) — ( 19.4 )

Due to affiliates 51.7 — 51.7

Ravenswood retiree legal settlement ( 2.0 ) — ( 2.0 )

PBGC Settlement ( 4.5 ) — ( 4.5 )

Other - net 2.8 — 2.8

Net cash provided by operating activities 105.6 — 105.6

CASH FLOWS FROM INVESTING ACTIVITIES:

Purchase of property, plant and equipment ( 95.0 ) — ( 95.0 )

Proceeds from sale of property, plant and equipment 25.7 — 25.7

Acquisition of subsidiary net of cash acquired 11.5 — 11.5

Net cash used in investing activities ( 57.8 ) — ( 57.8 )

CASH FLOWS FROM FINANCING ACTIVITIES:

Borrowing under revolving credit facilities 656.9 — 656.9

Repayments under revolving credit facilities ( 758.2 ) — ( 758.2 )

Borrowings under Grundartangi casthouse debt facility 55.0 — 55.0

Repayments under Iceland term facility ( 13.5 ) — ( 13.5 )

Borrowings under Vlissingen facility agreement 10.0 — 10.0

Carbon credit proceeds 36.8 — 36.8

Net cash used in financing activities ( 13.0 ) — ( 13.0 )

CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH 34.8 — 34.8

Cash, cash equivalents and restricted cash, beginning of year 55.5 — 55.5

Cash, cash equivalents and restricted cash, end of year $ 90.3 $ — $ 90.3

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The effects of the corrections described above on the Company's Consolidated Statements of Shareholder's Equity were as follows:

As Previously Reported Restatement Impacts As Restated

Noncontrolling Interest

Balance as of December 31, 2022 $ — $ — $ —

Net loss ( 9.2 ) ( 4.3 ) ( 13.5 )

Other comprehensive loss — ( 9.1 ) ( 9.1 )

Noncontrolling Interest of business acquired ( 2.3 ) 172.5 170.2

Balance as of December 31, 2023 $ ( 11.5 ) $ 159.1 $ 147.6

Net loss ( 16.1 ) ( 14.0 ) ( 30.1 )

Other comprehensive loss — ( 1.2 ) ( 1.2 )

Noncontrolling Interest of business acquired ( 4.0 ) ( 1.3 ) ( 5.3 )

Balance as of December 31, 2024 $ ( 31.6 ) $ 142.6 $ 111.0

As Previously Reported Restatement Impacts As Restated

Balance as of December 31, 2022 $ 399.3 — $ 399.3

Net loss ( 52.3 ) ( 4.3 ) ( 56.6 )

Other comprehensive income (loss) ( 3.9 ) ( 9.1 ) ( 13.0 )

Share based compensation 3.3 — 3.3

Conversion of preferred stock to common stock — — —

Noncontrolling Interest of business acquired ( 2.3 ) 172.5 170.2

Balance as of December 31, 2023 $ 344.1 $ 159.1 $ 503.2

Net loss 320.7 ( 14.0 ) 306.7

Other comprehensive income (loss) ( 5.4 ) ( 1.2 ) ( 6.6 )

Share-based compensation 7.3 — 7.3

Conversion of preferred stock to common stock — — —

Noncontrolling Interest of business acquired ( 4.0 ) ( 1.3 ) ( 5.3 )

Balance as of December 31, 2024 $ 662.7 $ 142.6 $ 805.3

The Company has also restated impacted amounts within the accompanying footnotes to the Consolidated Financial Statements.

Quarterly Financial Information (Unaudited and Restated)

As further discussed in Note 1.

Summary of Significant Accounti ng Policies and Note 2 2.

R estateme nt of Previously Issued Financial Statements , the Company determined that corrections to the unaudited condensed consolidated financial statements were required for all impacted periods previously included in each of the Company's Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2025, June 30, 2025, September 30, 2025, March 31, 2024, June 30, 2024, and September 30, 2024.

Restated amounts are computed independently for each quarter presented; therefore, the sum of the quarterly amounts may not equal the total amount for the year due to rounding.

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The restatement impacts to the Company's consolidated statements of operations were as shown below.

For the Three Months Ended March 31, 2024 For the Three Months Ended March 31, 2025

As Previously

Reported Restatement

Impacts As Restated As Previously

Reported Restatement

Impacts As Restated

Cost of Goods Sold $ 473.0 $ 3.5 $ 476.5 $ 573.3 $ 3.3 $ 576.6

Gross profit 16.5 ( 3.5 ) 13.0 60.6 ( 3.3 ) 57.3

Operating income (loss) 1.9 ( 3.5 ) ( 1.6 ) 46.1 ( 3.3 ) 42.8

Income before income taxes 245.2 ( 3.5 ) 241.7 27.3 ( 3.3 ) 24.0

Net income 244.7 ( 3.5 ) 241.2 25.7 ( 3.3 ) 22.4

Net loss attributable to noncontrolling interests ( 2.1 ) ( 3.5 ) ( 5.6 ) ( 4.0 ) ( 3.3 ) ( 7.3 )

Net income attributable to Century stockholders 246.8 — 246.8 29.7 — 29.7

Net income allocated to participating securities 13.2 — 13.2 1.5 — 1.5

Net income allocated to common stockholders $ 233.6 $ — $ 233.6 $ 28.2 $ — $ 28.2

For the Three Months Ended June 30, 2024 For the Three Months Ended June 30, 2025

As Previously

Reported Restatement

Impacts As Restated As Previously

Reported Restatement

Impacts As Restated

Cost of Goods Sold $ 540.4 $ 4.9 $ 545.3 $ 591.9 $ 2.6 $ 594.5

Gross profit 20.4 ( 4.9 ) 15.5 36.2 ( 2.6 ) 33.6

Operating income 6.4 ( 4.9 ) 1.5 20.7 ( 2.6 ) 18.1

Loss before income taxes ( 6.2 ) ( 4.9 ) ( 11.1 ) ( 10.4 ) ( 2.6 ) ( 13.0 )

Net loss ( 6.7 ) ( 4.9 ) ( 11.6 ) ( 9.1 ) ( 2.6 ) ( 11.7 )

Net loss attributable to noncontrolling interests ( 4.2 ) ( 4.9 ) ( 9.1 ) ( 4.5 ) ( 2.6 ) ( 7.1 )

Net loss attributable to Century stockholders ( 2.5 ) — ( 2.5 ) ( 4.6 ) — ( 4.6 )

Net income allocated to participating securities — — — — — —

Net loss allocated to common stockholders $ ( 2.5 ) $ — $ ( 2.5 ) $ ( 4.6 ) $ — $ ( 4.6 )

For the Three Months Ended

September 30, 2024 For the Three Months Ended

September 30, 2025

As Previously Reported Restatement Impacts As Restated As Previously Reported Restatement Impacts As Restated

Cost of Goods Sold $ 457.3 $ 4.9 $ 462.2 $ 554.9 $ 2.4 $ 557.3

Gross profit 81.8 ( 4.9 ) 76.9 77.3 ( 2.4 ) 74.9

Operating income 63.8 ( 4.9 ) 58.9 58.3 ( 2.4 ) 55.9

Income before income taxes 44.3 ( 4.9 ) 39.4 9.5 ( 2.4 ) 7.1

Net income 42.3 ( 4.9 ) 37.4 10.6 ( 2.4 ) 8.2

Net loss attributable to noncontrolling interests ( 5.0 ) ( 4.9 ) ( 9.9 ) ( 4.3 ) ( 2.4 ) ( 6.7 )

Net income attributable to Century stockholders 47.3 — 47.3 14.9 — 14.9

Net income allocated to participating securities 2.5 — 2.5 0.8 — 0.8

Net income allocated to common stockholders $ 44.8 $ — $ 44.8 $ 14.1 $ — $ 14.1

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The restatement impacts to the Company's consolidated balance statements were as shown below (dollars in millions).

March 31, 2024

As Previously Reported Restatement Impacts As Restated

Non-trade receivables 38.5 1.6 40.1

Total current assets 781.1 1.6 782.7

Property, plant and equipment - net 984.2 153.7 1,137.9

Other assets 84.6 1.1 85.7

TOTAL $ 1,849.9 $ 156.4 $ 2,006.3

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued benefits costs - less current portion 121.3 11.2 132.5

Asset retirement obligations - less current portion 50.4 12.8 63.2

Total noncurrent liabilities 793.9 24.0 817.9

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 14.4 ) 132.4 118.0

Total equity 587.1 132.4 719.5

TOTAL $ 1,849.9 $ 156.4 $ 2,006.3

June 30, 2024

As Previously Reported Restatement Impacts As Restated

Non-trade receivables 53.5 ( 6.6 ) 46.9

Total current assets 735.9 ( 6.6 ) 729.3

Property, plant and equipment - net 971.5 158.0 1,129.5

Other assets 97.8 1.0 98.8

TOTAL $ 1,805.2 $ 152.4 $ 1,957.6

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued benefits costs - less current portion 120.2 11.1 131.3

Asset retirement obligations - less current portion 49.9 12.2 62.1

Total noncurrent liabilities 794.2 23.3 817.5

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 18.6 ) 129.1 110.5

Total equity 582.9 129.1 712.0

TOTAL $ 1,805.2 $ 152.4 $ 1,957.6

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

September 30, 2024

As Previously Reported Restatement Impacts As Restated

Non-trade receivables 52.7 ( 2.9 ) 49.8

Total current assets 806.9 ( 2.9 ) 804.0

Property, plant and equipment - net 965.3 164.4 1,129.7

Other assets 124.7 1.0 125.7

TOTAL $ 1,896.9 $ 162.5 $ 2,059.4

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued benefits costs - less current portion 119.2 11.1 130.3

Asset retirement obligations - less current portion 54.1 15.4 69.5

Total noncurrent liabilities 796.1 26.5 822.6

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 23.6 ) 136.0 112.4

Total equity 628.5 136.0 764.5

TOTAL $ 1,896.9 $ 162.5 $ 2,059.4

March 31, 2025

As Previously Reported Restatement Impacts As Restated

Non-trade receivables — 7.7 7.7

Total current assets 821.9 7.7 829.6

Property, plant and equipment - net 972.2 169.8 1,142.0

Other assets 69.3 0.9 70.2

TOTAL $ 1,954.5 $ 178.4 $ 2,132.8

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued compensation and benefits 40.6 1.0 41.6

Nontrade payables 7.4 ( 7.4 ) —

Accrued and other current liabilities 36.6 2.6 39.2

Total current liabilities 447.4 ( 3.8 ) 443.6

Accrued benefits costs - less current portion 129.3 14.5 143.8

Asset retirement obligations - less current portion 64.4 20.7 85.1

Total noncurrent liabilities 816.4 35.2 851.6

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 35.6 ) 147.1 111.5

Total equity 690.7 147.1 837.8

TOTAL $ 1,954.5 $ 178.4 $ 2,132.8

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

June 30, 2025

As Previously Reported Restatement Impacts As Restated

Non-trade receivables — 17.1 17.1

Total current assets 790.3 17.1 807.4

Property, plant and equipment - net 975.6 175.2 1,150.8

Other assets 69.6 1.0 70.6

TOTAL $ 1,949.0 $ 193.3 $ 2,142.3

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued compensation and benefits 44.2 1.0 45.2

Nontrade payables 7.7 ( 7.7 ) —

Accrued and other current liabilities 44.9 3.1 48.0

Total current liabilities 451.1 ( 3.6 ) 447.5

Accrued benefits costs - less current portion 127.8 14.5 142.3

Asset retirement obligations - less current portion 63.2 19.3 82.5

Total noncurrent liabilities 813.6 33.8 847.4

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 40.1 ) 163.1 123.0

Total equity 684.3 163.1 847.4

TOTAL $ 1,949.0 $ 193.3 $ 2,142.3

September 30, 2025

As Previously Reported Restatement Impacts As Restated

Non-trade receivables — 19.8 19.8

Total current assets 1,027.1 19.8 1,046.9

Property, plant and equipment - net 972.2 167.0 1,139.2

Other assets 71.1 0.9 72.0

TOTAL $ 2,134.2 $ 187.7 $ 2,321.9

LIABILITIES AND SHAREHOLDERS’ EQUITY

Accrued compensation and benefits 52.4 1.0 53.4

Nontrade payables 11.8 ( 11.8 ) —

Accrued and other current liabilities 73.6 3.2 76.8

Total current liabilities 599.1 ( 7.6 ) 591.5

Accrued benefits costs - less current portion 121.8 14.5 136.3

Asset retirement obligations - less current portion 63.9 19.4 83.3

Total noncurrent liabilities 837.7 33.9 871.6

SHAREHOLDERS’ EQUITY:

Noncontrolling interests ( 44.4 ) 161.4 117.0

Total equity 697.4 161.4 858.8

TOTAL $ 2,134.2 $ 187.7 $ 2,321.9

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

The restatement impacts to the Company's consolidated statements of shareholders' equity as shown below (dollars in millions).

Three Months Ended March 31, 2024 Three Months Ended March 31, 2025

(As Previously Reported) Noncontrolling interest Total equity (As Previously Reported) Noncontrolling interest Total equity

Balance, December 31, 2023 $ ( 11.5 ) $ 344.1 Balance, December 31, 2024 $ ( 31.6 ) $ 662.7

Net income (loss) ( 2.1 ) 244.7 Net income (loss) ( 4.0 ) 25.7

Other comprehensive income (loss) — ( 1.7 ) Other comprehensive income (loss) — 1.7

Share-based compensation — 0.8 Share-based compensation — 0.6

Noncontrolling interest of business acquired ( 0.8 ) ( 0.8 ) Noncontrolling interest of business acquired — —

Balance, March 31, 2024 $ ( 14.4 ) $ 587.1 Balance, March 31, 2025 $ ( 35.6 ) $ 690.7

(Restatement Impacts) (Restatement Impacts)

Net income (loss) $ ( 3.5 ) $ ( 3.5 ) Net income (loss) $ ( 3.3 ) $ ( 3.3 )

Noncontrolling interest of business acquired ( 23.2 ) ( 23.2 ) Noncontrolling interest of business acquired 7.8 7.8

(As Restated) (As Restated)

Balance, December 31, 2023 147.6 503.2 Balance, December 31, 2024 111.0 805.3

Net income (loss) ( 5.6 ) 241.2 Net income (loss) ( 7.3 ) 22.4

Other comprehensive income (loss) — ( 1.7 ) Other comprehensive income (loss) — 1.7

Share-based compensation — 0.8 Share-based compensation — 0.6

Noncontrolling interest of business acquired ( 24.0 ) ( 24.0 ) Noncontrolling interest of business acquired 7.8 7.8

Balance, March 31, 2024 $ 118.0 $ 719.5 Balance, March 31, 2025 $ 111.5 $ 837.8

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Three Months Ended June 30, 2024 Three Months Ended June 30, 2025

(As Previously Reported) Noncontrolling interest Total equity (As Previously Reported) Noncontrolling interest Total equity

Balance, March 31, 2024 $ ( 14.4 ) $ 587.1 Balance, March 31, 2025 $ ( 35.6 ) $ 690.7

Net loss ( 4.2 ) ( 6.7 ) Net loss ( 4.5 ) $ ( 9.1 )

Other comprehensive income — 1.5 Other comprehensive income — $ 1.5

Share-based compensation — 1.0 Share-based compensation — $ 1.2

Noncontrolling interest of business acquired — — Noncontrolling interest of business acquired — $ —

Balance, June 30, 2024 $ ( 18.6 ) $ 582.9 Balance, June 30, 2025 $ ( 40.1 ) $ 684.3

(Restatement Impacts) (Restatement Impacts)

Net income (loss) $ ( 4.9 ) $ ( 4.9 ) Net income (loss) $ ( 2.6 ) $ ( 2.6 )

Noncontrolling interest of business acquired 1.6 1.6 Noncontrolling interest of business acquired 18.6 18.6

(As Restated) (As Restated)

Balance, March 31, 2024 $ 118.0 $ 719.5 Balance, March 31, 2025 $ 111.5 $ 837.8

Net loss ( 9.1 ) ( 11.6 ) Net loss ( 7.1 ) ( 11.7 )

Other comprehensive income (loss) — 1.5 Other comprehensive income (loss) — 1.5

Share-based compensation — 1.0 Share-based compensation — 1.2

Noncontrolling interest of business acquired 1.6 1.6 Noncontrolling interest of business acquired 18.6 18.6

Balance, June 30, 2024 $ 110.5 $ 712.0 Balance, June 30, 2025 $ 123.0 $ 847.4

Three Months Ended September 30, 2024 Three Months Ended September 30, 2025

(As Previously Reported) Noncontrolling interest Total equity (As Previously Reported) Noncontrolling interest Total equity

Balance, June 30, 2024 $ ( 18.6 ) $ 582.9 Balance, June 30, 2025 $ ( 40.1 ) $ 684.3

Net income (loss) ( 5.0 ) 42.3 Net loss ( 4.3 ) 10.6

Other comprehensive income — 1.7 Other comprehensive income — 1.5

Share-based compensation — 1.6 Share-based compensation — 1.0

Noncontrolling interest of business acquired — — Noncontrolling interest of business acquired — —

Balance, September 30, 2024 $ ( 23.6 ) $ 628.5 Balance, September 30, 2025 $ ( 44.4 ) $ 697.4

(Restatement Impacts) (Restatement Impacts)

Net income (loss) $ ( 4.9 ) $ ( 4.9 ) Net income (loss) $ ( 2.4 ) $ ( 2.4 )

Noncontrolling interest of business acquired 11.8 11.8 Noncontrolling interest of business acquired 0.7 0.7

(As Restated) (As Restated)

Balance, June 30, 2024 $ 110.5 $ 712.0 Balance, June 30, 2025 $ 123.0 $ 847.4

Net loss ( 9.9 ) 37.4 Net loss ( 6.7 ) 8.2

Other comprehensive income — 1.7 Other comprehensive income — 1.5

Share-based compensation — 1.6 Share-based compensation — 1.0

Noncontrolling interest of business acquired 11.8 11.8 Noncontrolling interest of business acquired 0.7 0.7

Balance, September 30, 2024 $ 112.4 $ 764.5 Balance, September 30, 2025 $ 117.0 $ 858.8

Table of Contents CENTURY ALUMINUM COMPANY

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS

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

Subsequent Events

New Smelter Project

On January 26, 2026, we announced that we had entered into a joint development agreement with Emirates Global Aluminium (“EGA”) to build the first new primary aluminum smelter in the United States since our Mt.

Holly facility came online in 1980.

Under the joint development agreement, EGA will own 60 percent of the joint venture, with Century Aluminum owning the remaining 40 percent.

The new plant, to be built in Inola, Oklahoma, is expected to produce 750,000 tonnes of aluminum per year, more than doubling current U.S.

Construction of the project is expected to start by the end of 2026, with detailed engineering work already and negotiations with Public Service Company of Oklahoma and the state of Oklahoma on a competitive long-term power supply underway.

Sale of Hawesville

On February 2, 2026, we completed the sale of our Hawesville, Kentucky facility to an affiliate of Terawulf, Inc.

for $ 200.0 million in cash and a 6.8 % non-dilutive minority equity interest in the Terawulf affiliate that intends to develop and own a high-performance computing/artificial intelligence data center on the site.

A large portion of the proceeds are intended to be deployed to expand our domestic primary aluminum production capacity through the restart of the last potline at our Mt.

Holly facility and investments in our new smelter project.

In connection with our sale of the Hawesville facility, on February 2, 2026, we terminated the letter of credit in the amount of $ 8.1 million under our U.S.

Credit Facility, effectively prepaying the IRBs.

As noted throughout this Form 10-K, on February 13, 2026, we terminated our labor agreement with United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union ("USW") for former employees at our Hawesville facility, the impacts for which are disclosed herein.

Changes in and Disagreements with Accountants on Accounting and Financial Disclosure

1 unchanged sentence

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-K

Item 8. Financial Statements and Supplementary Data