CENTURY ALUMINUM CO

Condensed Notes to the Consolidated Financial Statements

Nine months ended September 30, 2025 and 2024

1. General

Description of Business

Century Aluminum is a producer of primary aluminum, which trades as a global commodity, and owns a 55% interest in a bauxite mining and alumina refinery joint venture. We are organized as a holding company, with our operating primary aluminum smelters and our bauxite mining and alumina refinery joint venture owned by separate subsidiaries.

Throughout this Form 10-Q, and unless expressly stated otherwise or as the context otherwise requires, "Century Aluminum", "Century", "the Company", "we", "us", "our" and "ours" refer to Century Aluminum Company and its consolidated subsidiaries.

Basis of Presentation

The accompanying unaudited interim consolidated financial statements of Century Aluminum Company should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2024. In management’s opinion, the unaudited interim consolidated financial statements reflect all adjustments, which are of a normal and recurring nature, that are necessary for a fair presentation of financial results for the interim periods presented. Operating results for the first nine months of 2025 are not necessarily indicative of the results that may be expected for the year ending December 31, 2025.

Our consolidated financial statements include the consolidated results of the Jamalco joint venture ("Jamalco"), an unincorporated joint venture between Clarendon Alumina Production Limited ("CAP") and General Alumina Jamaica Limited ("GAJL"), an indirect, wholly-owned subsidiary of the Company through General Alumina Holdings Limited ("GAHL"). CAP's interest in the joint venture is reflected as noncontrolling interest on the accompanying Consolidated Balance Sheets. The acquisition of all the outstanding capital of GAHL was accounted for as a business combination under the acquisition method of accounting in accordance with the Business Combinations Topic of the FASB Accounting Standards Codification ("ASC"), resulting in the Company recognizing the assets and liabilities at fair value with the excess of fair value over the consideration paid to the seller presented as a bargain purchase gain of $245.9 million recognized within the Consolidated Statements of Operations for the nine months ended September 30, 2024.

Recent Accounting Pronouncements

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 for its consolidated financial statements and related disclosures for the annual period ending December 31, 2025.

In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): 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. The standard also requires a qualitative description of other amounts included in each relevant expense line item on the income statement that are not separately disclosed. In addition, entities are required to disclose the nature and amount of selling expenses. The new standard is effective for fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Early adoption is permitted. We do not expect any impact to the consolidated financial statements, but the standard will require certain additional disclosures. The Company plans to adopt this guidance for the annual period ending December 31, 2027.

2. Related Party Transactions

The significant related party transactions occurring during the three and nine months ended September 30, 2025 and 2024 are described below. All of our related party transactions are subject to the Company's Related Party Transaction Policy and are required to be made on an arm's length basis and on terms that are fair and reasonable to the Company and substantially the same as would apply if the other party was not a related party. We believe all of our transactions with related parties are at prices that approximate market.

Glencore Ownership

As of September 30, 2025, 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. See Note 13. Shareholders' Equity for a description of our outstanding Series A Convertible Preferred Stock. Century and Glencore enter into various transactions from time to time, such as the purchase and sale of primary aluminum, alumina and other raw materials; tolling agreements; forward financial contracts and borrowing and other debt transactions.

Sales to Glencore

For the three months ended September 30, 2025 and 2024, we derived approximately 50.6% and 61.6%, respectively, of our consolidated net sales from Glencore. For the nine months ended September 30, 2025 and 2024, we derived approximately 56.3% and 61.0%, respectively, of our consolidated net sales from Glencore.

Glencore purchases aluminum produced at our U.S. smelters at prices based on the London Metal Exchange ("LME") plus the Midwest regional delivery premium plus any additional market-based product premiums. Glencore purchases aluminum produced at our Grundartangi, Iceland smelter at prices based on the LME plus the European Duty Paid premium plus any additional market-based product premiums.

We have entered into agreements with Glencore pursuant to which we sell certain amounts of alumina at market-based prices. For the three and nine months ended September 30, 2025, the Company recognized $34.8 million and $161.2 million, respectively, of revenue related to alumina sales to Glencore. For thethree and nine months ended September 30, 2024, the Company recognized $31.5 million and $117.3 million, respectively, of revenue related to alumina sales to Glencore.

Purchases from Glencore

We purchase a portion of our alumina and certain other raw material requirements from Glencore. Alumina purchases from Glencore during the three and nine months ended September 30, 2025 and 2024 were priced based on published alumina and aluminum indices as well as fixed prices.

Financial Contracts with Glencore

From time to time, we enter into certain financial contracts with Glencore. See Note 10. Derivatives regarding these forward financial sales contracts.

Summary

A summary of the aforementioned significant related party sales and purchases is as follows:

(1)Includes settlements of financial contract positions.

Vlissingen Credit Facility

On December 9, 2022, Vlissingen entered into a Facility Agreement with Glencore International AG, which was amended and extended on October 1, 2024 (as amended, the “Vlissingen Credit Facility”). The availability period for borrowings under the Vlissingen Credit Facility was extended bytwo years and now ends on December 2, 2026. Under the Vlissingen Credit Facility, Vlissingen may borrow from time to time up to $90.0 million in one or more loans at either (i) a fixed interest rate equal to 8.75% per annum (the “Fixed Rate”), or (ii) a variable interest rate equal to the 1-month SOFR rate plus 3.687 percentage points, subject to an absolute maximum level of 9.00% and an absolute minimum level of 7.00% (the “Variable Rate”). 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. See Note 11. Debt for additional information. Borrowings under the Vlissingen Credit Facility are expected to be used for general corporate and working capital purposes of Century and its subsidiaries.

Carbon Credit Repurchase Agreement

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.

In 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 retains 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.

3. Revenue

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. For aluminum, 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. For alumina, consideration 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.

Contract liabilities are recorded when cash payments are received or due in advance of performance. Amounts recognized in Due to affiliates was $41.4 million and $41.2 million, as of September 30, 2025 and December 31, 2024, respectively.

The table below shows the amount of net sales to external customers for each of the Company's product categories which accounted for 10% or more of consolidated net sales in either period for the three and nine months ended September 30, 2025 and 2024.

Our net sales are attributed to geographic area based on the location of the selling entity. Included in the consolidated financial statements are the following amounts related to geographic locations:

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

4. Income Taxes

For the three months ended September 30, 2025 and 2024, we recorded an income tax benefit of $1.1 million and an income tax expense of $2.0 million, respectively. For the nine months ended September 30, 2025 and 2024, we recorded an income tax benefit of $0.8 million and an income tax expense of $3.0 million, respectively. The change is primarily due to changes in pretax income amounts and jurisdictional mix on a year over year basis.

Our income tax expense or benefit for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items. The application of the accounting requirements for income taxes in interim periods, after consideration of our valuation allowance on domestic losses, causes a significant variation in the typical relationship between income tax expense/benefit and pretax accounting income/loss as reported on the Consolidated Statements of Operations.

As of September 30, 2025, all of Century's U.S. and certain foreign deferred tax assets, net of deferred tax liabilities, continue to be subject to a full valuation allowance.

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 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 three months ended September 30, 2025 and 2024, the Company recognized a reduction of $24.7 million and $47.3 million in Cost of goods sold and a reduction of $0.7 million and $0.8 million in Selling, general and administrative expenses, respectively, within the Consolidated Statements of Operations. For the nine months ended September 30, 2025 and 2024, the Company recognized a reduction of $66.5 million and $69.9 million in Cost of goods sold and a reduction of $2.0 million and $2.0 million in Selling, general and administrative expenses, respectively, within the Consolidated Statements of Operations.

President Trump signed Public Law No: 119-21, the One Big Beautiful Bill Act (the "Act") into law on July 4, 2025, which marks the date of enactment for the tax provisions included in the Act. 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 three and nine months ended September 30, 2025. We will continue to evaluate the effects of the Act on our results as further guidance is issued.

5. Earnings Per Share

Basic earnings per share ("EPS") amounts are calculated by dividing earnings available to common stockholders by the weighted average number of common shares outstanding using the two-class method. Diluted EPS 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. Dilutive common equivalent shares are calculated using the more dilutive of either the if-converted or two-class methods.

The following table shows the basic and diluted earnings per share:

(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.

6. Accumulated Other Comprehensive Loss ("AOCL")

(1)The allocation of the income tax effect to the components of other comprehensive loss is as follows:

The following table summarizes the changes in the accumulated balances for each component of AOCL:

Reclassifications out of AOCL were included in the Consolidated Statements of Operations as follows:

7. Components of Net Periodic Benefit Cost

8. Inventories

Inventories consist of the following:

Inventories are stated at the lower of cost or Net Realizable Value ("NRV") using the first-in, first-out or the weighted average cost method.

9. Fair Value Measurements

We measure and classify certain of our assets and liabilities at fair value in accordance with the hierarchy as defined by the Fair Value Measurment Topic of the FASB ASC. The fair value hierarchy provides transparency regarding the inputs we use to measure fair value. We categorize each fair value measurement in its entirety into the following three levels, based on the lowest level input that is significant to the entire measurement:

•Level 1 Inputs - quoted prices (unadjusted) in active markets for identical assets or liabilities that we can access at the measurement date.

•Level 2 Inputs - inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly.

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

(1)Trust assets are currently invested in money market funds. These trust assets are held to fund the non-qualified supplemental executive pension benefit obligations for certain of our officers.

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

When valuing Level 3 assets and liabilities, we use certain significant unobservable inputs. Management incorporates various inputs and assumptions including forward commodity prices, commodity price volatility and macroeconomic conditions, including interest rates and discount rates. Our estimates of significant unobservable inputs are ultimately based on our estimates of risks that market participants would consider when valuing our assets and liabilities.

During the three and nine months ended September 30, 2025 and 2024, there were no Level 3 assets and liabilities measured at fair value on a recurring basis.

10. Derivatives

As of September 30, 2025, we had an open position of 49,800 tonnes related to LME forward financial sales contracts to fix the forward LME aluminum price. These contracts are expected to settle monthly through December 2026. We also had an open position of 83,400 tonnes related to MWP forward financial sales contracts to fix the forward MWP price. These contracts are expected to settle monthly through December 2027. 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 September 30, 2025, we had 272 tonnes open fixed for floating swaps. These contracts are expected to settle monthly through November 2025.

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 September 30, 2025, we had an open position of 280,000 barrels. The HFO price swaps are expected to settle monthly through September 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 September 30, 2025, we had an open position of 913,680 MWh. The Indiana Hub power price swaps are expected to settle monthly through December 2026.

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 September 30, 2025 and December 31, 2024, the Company hadno recorded restricted cash as collateral related to open derivative contracts under the master arrangements with our counterparties.

The following tables set forth the Company's derivative assets and liabilities that were accounted for at fair value and not designated as cash flow hedges as of September 30, 2025 and December 31, 2024, respectively:

(1)Commodity contracts reflect our outstanding LME and MWP forward financial sales contracts, Indiana Hub power price swaps, fixed for floating swaps, and HFO price swaps. At September 30, 2025, and December 31, 2024, there wereno commodity contracts with Glencore.

The following table summarizes the net loss on forward and derivative contracts:

(1)For the three and nine months ended September 30, 2025, there wereno forward and derivative contracts with Glencore. For the three and nine months ended September 30, 2024, $1.2 million of the net loss and a $3.7 million gain within the net loss, respectively, was with Glencore.

11. Debt

(1)The IRBs are classified as current liabilities because they are remarketed weekly and could be required to be repaid upon demand if there is a failed remarketing. The interest rate at September 30, 2025 was 3.02%.

(2)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at September 30, 2025 was 7.75%.

(3)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at September 30, 2025 was 7.66%.

(4)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at September 30, 2025 was 7.89%.

(5)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at September 30, 2025 was 7.83%.

6.875% Senior Secured Notes due 2032

In July 2025, we issued $400.0 million in aggregate principal amount of 6.875% of senior secured notes due August 1, 2032 (the "2032 Notes"). We received proceeds of $393.7 million after payment of certain financing fees and related expenses. 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% in cash. The 2032 Notes are senior secured obligations of Century, ranking equally in right of payment with all of the Company’s existing and future senior indebtedness, effectively senior to all of the Company’s unsecured indebtedness to the extent of the value of the collateral and senior to all of the Company’s existing and future subordinated indebtedness.

As of September 30, 2025, the total estimated fair value of the 2032 Notes was $415.6 million. 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

In April 2021, we completed a private offering of $86.3 million aggregate principal amount of convertible senior notes due May 1, 2028 unless earlier converted, repurchased, or redeemed (the "Convertible Notes"). The Convertible Notes were issued at a price of 100% of their aggregate principal amount. We received proceeds of $83.7 million, after payment of certain financing fees and related expenses. The Convertible Notes bear interest semi-annually in arrears on May 1 and November 1 of each year at a rate of 2.75% per annum in cash.

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. Asof September 30, 2025, the conversion rate remains unchanged.

The Convertible Notes are the Company’s senior unsecured obligations and rank senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the Convertible Notes; equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated; effectively junior in right of payment to any of the Company’s senior secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries.

As of September 30, 2025, the if-converted value of the Convertible Notes exceeded the outstanding principal amount by $48.9 million.

As of September 30, 2025, the total estimated fair value of the Convertible Notes was$140.7 million. 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.

U.S. Revolving Credit Facility

We and certain of our direct and indirect domestic subsidiaries have a senior secured revolving credit facility with a syndicate of lenders (as amended from time to time, the "U.S. revolving credit facility"). On June 14, 2022 we amended our U.S. revolving credit facility, increasing our borrowing capacity to $250.0 million in the aggregate, including up to $150.0 million under a letter of credit sub-facility. 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 September 30, 2025, there wereno outstanding borrowings and $49.5 millionof outstanding letters of credit issued under our U.S. revolving credit facility. Principal payments, if any, are due upon maturity of the U.S. revolving credit facility and may be prepaid without penalty.

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. On September 28, 2022, we further amended the Iceland revolving credit facility and increased the facility amount 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. At September 30, 2025, there were $16.5 million outstanding borrowings under our Iceland revolving credit facility. The Iceland revolving credit facility matures in December 2026.

Grundartangi Casthouse Facility

On November 2, 2021, in connection with the casthouse project at Grundartangi, we entered into aneight-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 September 30, 2025, there were $115.0 million in outstanding borrowings under the Casthouse Facility, which was classified as a current liability as we repaid all outstanding borrowings under the Casthouse Facility on October 27, 2025.

Vlissingen Credit Facility

On December 9, 2022, Vlissingen entered into a $90.0 million Facility Agreement with Glencore International AG, which was amended and extended on October 1, 2024 (as amended, the "Vlissingen Credit Facility"). The availability period for borrowings under the Vlissingen Credit Facility was extended bytwo years and now ends on December 2, 2026. Pursuant to the terms of the Vlissingen Credit Facility, Vlissingen may borrow from time to time up to $90.0 million in one or more loans at either (i) a fixed interest rate equal to 8.75% per annum (the "Fixed Rate"), or (ii) a variable interest rate equal to the 1-month SOFR rate plus 3.687 percentage points, subject to an absolute maximum level of 9.00% and an absolute minimum level of 7.00% (the "Variable Rate"). 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. On August 1, 2025, we repaid all outstanding borrowings under the Vlissingen Credit Facility.

Hancock County Industrial Revenue Bonds

As part of the purchase price for our acquisition of the Hawesville facility, we assumed IRBs which were issued in connection with the financing of certain solid waste disposal facilities constructed at the Hawesville facility. The IRBs bear interest at a variable rate not to exceed 12% per annum determined weekly based upon prevailing rates for similar bonds in the industrial revenue bond market and interest on the IRBs is paid quarterly. The IRBs are secured by a letter of credit issued under our U.S. revolving credit facility and mature in April 2028.

Surety Bond Facility

As part of our normal business operations, we are required to provide surety bonds or issue letters of credit in certain states in which we do business as collateral for certain workers' compensation obligations. In June 2022, we entered into a surety bond facility with an insurance company to provide such bonds when applicable. As of September 30, 2025, we had issued surety bonds totaling$6.6 million.

Covenant Compliance

As of September 30, 2025, we and our subsidiaries were in compliance with financial covenants or maintained availability above applicable covenant triggers.

12. Commitments and Contingencies

We have pending against us or may be subject to various lawsuits, claims and proceedings related primarily to employment, commercial, stockholder, environmental, safety and health matters and are involved in other matters that may give rise to contingent liabilities. 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 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. For some matters, no accrual is established because we have assessed our risk of loss to be remote. Where the risk of loss is probable and the amount of the loss can be reasonably estimated, we record an accrual, either on an individual basis or with respect to a group of matters involving similar claims, based on the factors set forth above. While we regularly review the status of, and our estimates of potential liability associated with, contingencies to determine the adequacy of any associated accruals and related disclosures, the ultimate amount of loss may differ from our estimates.

Legal Contingencies

Ravenswood Retiree Medical Benefits

In November 2009, Century Aluminum of West Virginia ("CAWV") filed a class action complaint for declaratory judgment against the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union ("USW"), the USW’s local and certain CAWV retirees, individually and as class representatives ("CAWV Retirees"), seeking a declaration of CAWV’s rights to modify/terminate retiree medical benefits. Later in November 2009, the USW and representatives of a retiree class filed a separate suit against CAWV, Century Aluminum Company, Century Aluminum Master Welfare Benefit Plan, and various John Does with respect to the foregoing. On August 18, 2017, the District Court for the Southern District of West Virginia approved a settlement agreement in respect of these actions, pursuant to the agreement, CAWV agreed to make payments into a trust for the benefit of the CAWV Retirees in the aggregate amount of $23.0 million over the course of 10 years. Upon approval of the settlement, we paid $5.0 million to the aforementioned trust in September 2017 and recognized a gain of $5.5 million to arrive at the then-net present value of $12.5 million. CAWV has agreed to pay the remaining amounts under the settlement agreement in annual increments of $2.0 million fornine years. As of September 30, 2025,$1.9 million was recorded in Accrued and other current liabilities.

PBGC Settlement

In 2013, we entered into a settlement agreement with the Pension Benefit Guaranty Corporation (the "PBGC") regarding an alleged "cessation of operations" at our Ravenswood facility (the "PBGC Settlement Agreement"). Pursuant to the terms of the PBGC Settlement Agreement, we agreed to make additional contributions (above any minimum required contributions) to our defined benefit pension plans totaling approximately $17.4 million. Under certain circumstances, in periods of lower primary aluminum prices relative to our cost of operations, we were able to defer one or more of these payments, provided that we provide the PBGC with acceptable security for such deferred payments. We historically elected to defer certain payments under the PBGC Settlement Agreement and provided the PBGC with the appropriate security. In October 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 the next four years beginning on November 30, 2022 and ending on November 30, 2025, subject to acceleration if certain terms and conditions are met in such amendment. As of September 30, 2025, we have made all contributions under the Amended PBGC Settlement Agreement.

Power Commitments and Contingencies

Hawesville and Sebree

Hawesville and Sebree each 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 these arrangements, Hawesville and Sebree get 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 Hawesville and Sebree. Century Marketer's power supply arrangement with Kenergy has an effective term through May 31, 2028, with automaticone-year extensions unless either party providesone-year notice of termination prior to the May 31 anniversary date. Similarly, Kenergy's power supply contracts with Hawesville and Sebree both have a term through December 31, 2026, with automaticone-year extensions unless either party providesone-year notice of termination prior to the December 31 anniversary date.

Mt. Holly

Century Aluminum of South Carolina ("CASC") has a power supply agreement with Santee Cooper that has an effective term through December 2031. Under this power supply agreement,100% of Mt. Holly’s electrical power requirements are supplied from Santee Cooper’s generation at cost of service based rates. The contract provides sufficient energy to allow Mt. Holly to operate at full production capacity.

Grundartangi

Grundartangi has power purchase agreements for approximately 545 MW of aggregate power with HS Orka hf ("HS"), Landsvirkjun and Orkuveita Reykjavikur ("OR"). These power purchase agreements expire on various dates from 2026 through 2036 (subject to extension). The power purchase agreements with each of HS and OR provide power at LME-based variable rates for the duration of these agreements. The larger Landsvirkjun agreement provides for fixed rate with an additional variable rate linked to the LME. Grundartangi also has a separate 25 MW power purchase agreement with Landsvirkjun at an LME-based variable rate.

Other Commitments and Contingencies

Labor Commitments

The bargaining unit employees at our Grundartangi, Vlissingen, Hawesville, Sebree and Jamalco facilities are represented by labor unions, representing approximately 58% of our total workforce.

Approximately 87% of Grundartangi’s work force is represented byfive labor unions, governed by a labor agreement that establishes wages and work rules for covered employees. This agreement is effective through December 31, 2030.

100% of Vlissingen's work force 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. The FME negotiates working conditions with trade unions on behalf of its members, which, when agreed upon, are then applicable to all employees of Vlissingen. The current labor agreement is effective through December 31, 2025.

Approximately 37% 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 the USW for its employees is effective through October 28, 2028. Mt. Holly employees are not represented by a labor union.

Approximately 62% of Jamalco’s work force is represented by the Union of Technical, Administrative, and Supervisory Personnel ("UTASP") through separately negotiated labor agreements for hourly and salaried employee groups. Both contracts were effective through December 31, 2023. Jamalco is currently in the process of negotiating new contracts with both the salaried and hourly employee groups. Until new contracts are reached, employees will continue to operate under the current agreements.

Contingent obligation

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 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 September 30, 2025, the principal and accrued interest for the contingent obligation was$33.4 million, which was fully offset by a derivative asset. We may be required to make installment payments for the contingent obligation in the future. These payments are contingent based on the LME price of primary aluminum and the level of Hawesville’s operations. Interest accrues at an annual rate equal to 10.94%. As of September 30, 2025, based on the curtailment of Hawesville's operations, 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. There can be no assurance that circumstances will not change thus accelerating the timing of such payments.