Debt

3 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

Debt

12.    Debt

	March 31, 2026		December 31, 2025
Debt classified as current liabilities:
Hancock County industrial revenue bonds ("IRBs") due April 1, 2028, interest payable quarterly(1)	$	—	$	7.8
U.S. Revolving Credit Facility(2)	—		—
Iceland Revolving Credit Facility(3)	66.1		61.0
Debt classified as non-current liabilities:
2.75% convertible senior notes due May 1, 2028, net of financing fees of $0.7 million at March 31, 2026, interest payable semiannually	85.5		85.5
6.875% senior secured notes due August 1, 2032, net of financing fees of $5.8 million at March 31, 2026, interest payable semiannually	394.3		394.0
Total	$	545.9	$	548.3

(1)The IRBs were classified as current liabilities because they were remarketed weekly and could have been required to be repaid upon demand if there is a failed remarketing.

(2)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at March 31, 2026 was 7.25%.

(3)We incur interest at a base rate plus applicable margin as defined within the agreement. The interest rate at March 31, 2026 was 7.18%.

6.875% Senior Secured Notes due 2032

General. On July 22, 2025, we issued $400.0 million in aggregate principal amount of 6.875% of senior secured notes (the "2032 Notes"). We received proceeds of $393.7 million after payment of certain financing fees and related expenses.

Interest Rate. 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.

Maturity. The 2032 Notes will mature on August 1, 2032, unless earlier repurchased or redeemed.

Seniority. 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.

Guaranty. Our obligations under the 2032 Notes are guaranteed by all of our existing and future domestic restricted subsidiaries (the “Guarantor Subsidiaries”), except for foreign owned holding companies, any domestic restricted subsidiary that owns no assets other than equity interests or other investments in foreign subsidiaries and certain immaterial subsidiaries, which guaranty shall in each case be a senior secured obligation of such Guarantor Subsidiaries, ranking equally in right of payment with all existing and future senior indebtedness of such Guarantor Subsidiaries but effectively senior to unsecured debt to the extent of the value of collateral.

Collateral. 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):

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

(ii) all equity interests in subsidiaries directly owned by Century or any Guarantor Subsidiaries; and

(iii) proceeds of the foregoing.

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. The collateral agent for the 2032 Notes will agree with the collateral agent for the other debt holders and us under such circumstances to enter into an intercreditor agreement that will cause the liens securing the 2032 Notes to be contractually subordinated to the liens securing such additional debt.

Redemption Rights. 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
2028	103.438%
2029	101.719%
2030 and Thereafter	100.000%

Upon a change of control (as defined in the indenture governing the 2032 Notes), we will be required to make an offer to purchase the 2032 Notes at a purchase price equal to 101% of the outstanding principal amount of the 2032 Notes on the date of the purchase, plus accrued and unpaid interest to, but not including, the date of purchase.

Covenants. The indenture governing the 2032 Notes contains customary covenants which may limit our ability, and the ability of certain of our subsidiaries, to: (i) incur additional debt; (ii) incur additional liens; (iii) pay dividends or make distributions in respect of capital stock; (iv) purchase or redeem capital stock; (v) make investments or certain other restricted payments; (vi) sell assets; (vii) issue or sell stock of certain subsidiaries; (viii) enter into transactions with shareholders or affiliates; and (ix) effect a consolidation or merger.

As of March 31, 2026, the total estimated fair value of the 2032 Notes was $413.7 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.

2.75% Convertible Notes due 2028

General. On April 9, 2021, we completed a private offering of $86.3 million aggregate principal amount of convertible senior notes 2028 (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 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. As of March 31, 2026, the conversion rate remains unchanged.

Interest Rate. 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.

Maturity. The Convertible Notes will mature on May 1, 2028, unless earlier converted, repurchased, or redeemed.

Seniority. 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.

Redemption Rights. 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.

Upon conversion, we may satisfy our conversion obligation by paying or delivering, as applicable, cash, shares of our common stock or a combination of cash and shares of our common stock, at our election, based on the applicable conversion rate. In addition, if certain corporate events that constitute a make-whole fundamental change (as defined in the indenture) occur, then the conversion rate will, in certain circumstances, be increased for a specified period of time. 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 March 31, 2026, the if-converted value of the Convertible Notes exceeded the outstanding principal amount by $158.8 million.

Fair Value. As of March 31, 2026, the total estimated fair value of the Convertible Notes was $270.9 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

General. 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 March 31, 2026, there were no outstanding borrowings and $47.9 million of 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.

Status of our U.S. revolving credit facility:	March 31, 2026
Credit facility maximum amount	$	250.0
Borrowing availability	202.7
Outstanding letters of credit issued	47.9
Outstanding borrowings	—
Borrowing availability, net of outstanding letters of credit and borrowings	154.8

Borrowing Base. The availability of funds under the U.S. revolving credit facility is limited by a specified borrowing base consisting of the Borrower's accounts receivable and inventory which meets the eligibility criteria.

Guaranty. The Borrowers' obligations under the U.S. revolving credit facility are guaranteed by certain of our domestic subsidiaries and secured by a continuing lien upon and a security interest in all of the Borrowers' accounts receivable, inventory and certain bank accounts. Each Borrower is liable for any and all obligations under the U.S. revolving credit facility on a joint and several basis.

Interest Rates and Fees. Any amounts outstanding under the U.S. revolving credit facility will bear interest at our option of either the secured overnight financing rate ("SOFR") or a base rate, plus, in each case, an applicable interest margin. The applicable interest margin is determined based on the average daily availability for the immediately preceding quarter. In addition, we pay an unused line fee on undrawn amounts, less the amount of our letters of credit exposure. 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.

Prepayments. We can make prepayments of amounts outstanding under the U.S. revolving credit facility, in whole or in part, without premium or penalty, subject to standard breakage costs, if applicable. We may be required to apply the proceeds from sales of collateral accounts, other than sales of inventory in the ordinary course of business, to repay amounts outstanding under the revolving credit facility and correspondingly reduce the commitments there under.

Covenants. The U.S. revolving credit facility contains customary covenants, including restrictions on mergers and acquisitions, indebtedness, affiliate transactions, liens, dividends and distributions, dispositions of collateral, investments, and prepayments of indebtedness, as well as a covenant that requires the Borrowers to maintain certain minimum liquidity or availability requirements.

Events of Default. The U.S. revolving credit facility also includes customary events of default, including nonpayment, misrepresentation, breach of covenant, bankruptcy, change of ownership, certain judgments and certain cross defaults. Upon the occurrence of an event of default, commitments under the U.S. revolving credit facility may be terminated and amounts outstanding may be accelerated and declared immediately due and payable.

Iceland Revolving Credit Facility

General. 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. At March 31, 2026, there were $66.0 million outstanding borrowings under our Iceland revolving credit facility. The Iceland revolving credit facility matures in December 2026.

Status of our Iceland revolving credit facility:	March 31, 2026
Credit facility maximum amount	$	100.0
Borrowing availability	100.0
Outstanding letters of credit issued	—
Outstanding borrowings	66.0
Borrowing availability, net of borrowings	34.0

Borrowing Base. The availability of funds under the Iceland revolving credit facility is limited by a specified borrowing base consisting of inventory and accounts receivable of Grundartangi.

Security. Grundartangi's obligations under the Iceland revolving credit facility are secured by a general bond under which Grundartangi's inventory and accounts receivable are pledged to secure full payment of the loan.

Interest Rates and Fees. Any amounts outstanding under the Iceland revolving credit facility will bear interest at SOFR plus a margin per annum.

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

Covenants. 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.

Events of Default. The Iceland revolving credit 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 Iceland revolving credit facility may be terminated and amounts outstanding may be accelerated and declared immediately due and payable.

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 by two 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. As of March 31, 2026, there were no outstanding borrowings under the Vlissingen Credit Facility.

Security. 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.

Interest Rates and Fees. Amounts outstanding under the Vlissingen Credit Facility will bear interest at 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%.

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

Covenants. The Vlissingen Credit Facility contains customary covenants including with respect to mergers, guarantees and preservation and dispositions of assets.

Events of Default. The Vlissingen Credit Facility also includes customary events of default, including nonpayment, breach of any provision or representation under the agreement, and certain cross-default and insolvency events. Upon the occurrence of an event of default, commitments under the Vlissingen Credit Facility may be terminated and amounts outstanding may be accelerated and declared immediately due and payable.

Covenant Compliance

As of March 31, 2026, we and our subsidiaries were in compliance with financial covenants or maintained availability above applicable covenant triggers.

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 were secured by a letter of credit in the amount issued under our U.S. revolving credit facility and mature in April 2028. In connection with our sale of the Hawesville facility, on February 2, 2026, we effected a final draw under the letter of credit, defeased the IRBs and related Indenture, and irrevocably directed the Trustee to redeem the IRBs on April 1, 2026. Immediately following the final draw under the letter of credit, we terminated the letter of credit. As a result of the defeasance, the IRBs were considered extinguished as of February 2, 2026. The Trustee redeemed the IRBs on April 1, 2026.

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 March 31, 2026, we had issued surety bonds totaling $6.6 million.