What changed in this filing

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Item 1. Business

2026-03-03 compared with 2025-03-03 · 57 added, 81 removed, 197 unchanged (41% of the section changed)

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Our smelters produce standard-grade and value-added primary aluminum products.

Our current annual production capacity is approximately 1,020,000 tonnes per year ("tpy"), of which approximately 308,000 tpy was curtailed as of December 31, 2024 .

Our current annual production capacity was approximately 770,000 tonnes per year ("tpy") as of December 31, 2025.

We produced approximately 638,000 tonnes of primary aluminum in 2025.

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Century's share of Jamalco's production capacity is approximately 770,000 tpy.

The Jamalco refinery supplies a substantial amount of the alumina used for production of primary aluminum at our aluminum smelter in Grundartangi, Iceland.

We also own a carbon anode production facility located in the Netherlands ("Vlissingen").

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Through our Natur-Al TM product line, we are able to provide our customers with world-class, low-carbon aluminum products that demonstrate our commitment to sustainability.

We operate our business through one reportable segment, primary aluminum.

Additional information about our segment reporting and certain geographic information is available in Note 19.

We operate our business on a consolidated basis, through one operating segment and thus, one reportable segment.

Additional information about our segment reporting is available in Note 19.

Business Segments to the Consolidated Financial Statements included herein.

Century Aluminum Company is a Delaware corporation with our principal executive offices located at One South Wacker Drive, Suite 1000, Chicago, Illinois 60606.

Recent Developments

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.

See “New Smelter Project” below.

On February 2, 2026, we sold our aluminum smelter property in Hawesville, Kentucky, which had been fully curtailed since 2022, to an affiliate of Terawulf Inc.

for $200.0 million and a 6.8% non-dilutive interest in a data center project to be built on that property.

See “Sale of Hawesville” below.

Primary Aluminum Facilities

Overview of Facilities

We operate three U.S.

aluminum smelters, in Hawesville, Kentucky ("Hawesville"), currently curtailed, Robards, Kentucky ("Sebree") and Goose Creek, South Carolina ("Mt.

We operate two U.S.

aluminum smelters, in Robards, Kentucky ("Sebree") and Goose Creek, South Carolina ("Mt.

Holly"), and one aluminum smelter in Grundartangi, Iceland ("Grundartangi").

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Grundartangi, Iceland 100% 1998 320,000 260,000

Hawesville, Kentucky, USA 100% 1970 250,000 —

Sebree, Kentucky, USA 100% 1973 220,000 217,000

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Grundartangi produces standard-grade aluminum ingot and a value-added product called primary foundry alloy, which is sold at a premium to standard-grade aluminum.

In 2024, Century completed construction of a new billet casthouse at Grundartangi (the “Casthouse Project”).

The new billet casthouse has the capacity to produce 150,000 tonnes of value-added billet.

The Casthouse Project will also increase Grundartangi’s annual capacity to produce value-added primary foundry alloys from 60,000 tonnes of capacity to 120,000 tonnes of capacity.

This incremental billet and primary foundry alloy capacity displaces standard-grade ingot production, raising expected total value-added product premiums for Grundartangi products.

The billet produced at the Grundartangi casthouse is expected to be Natur-Al TM branded billet, our low-carbon aluminum brand .

Hawesville, located adjacent to the Ohio River near Hawesville, Kentucky, is a primary aluminum smelter owned by our wholly-owned subsidiary, Century Kentucky, Inc.

Hawesville has an annual production capacity of approximately 250,000 tonnes of primary aluminum.

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

We continue to explore all options related to the Hawesville facility, and have engaged financial advisors and launched a formal process to evaluate strategic alternatives and potential value to help us in our overall evaluation of this asset .

In October 2025, Grundartangi was forced to temporarily idle production on the larger one of its two potlines due to an electrical equipment failure.

As a result, production at the smelter has been temporarily reduced by approximately two-thirds.

Grundartangi’s other smaller potline remains unaffected and in full production.

We expect that losses arising from this event, less applicable deductibles, will be covered under our insurance policies.

We currently estimate that resumption of production of the idled potline will begin by the end of April 2026.

Sebree, located adjacent to the Green River near Robards, Kentucky, is a primary aluminum smelter owned and operated by our wholly-owned subsidiary, Century Aluminum Sebree LLC ("Century Sebree").

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The initial phase was completed in 2022 and returned annual active production capacity to approximately 172,500 MT per annum (75% of capacity).

Any potential future restart of Mt.

Holly's curtailed capacity will be made in the context of then-current market conditions

In August 2025, we began a project to restore the remaining curtailed capacity at Mt.

We expect to achieve full production by end of June 2026.

Holly produces standard-grade aluminum that is cast into sow as well as several value-added products, including billet and foundry products.

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Carbon Anode Production Facility

In addition to our primary aluminum assets, we own a carbon anode production facility located in Vlissingen, Netherlands, which is owned and operated by our wholly-owned subsidiary, Century Aluminum Vlissingen B.V.

Vlissingen has an annual carbon anode production capacity of approximately 163,000 tonnes.

Vlissingen supplies anodes primarily to our Grundartangi smelter, meeting 93% to 98% of Grundartangi’s carbon anodes requirements at current production levels.

Each of our smelters in the United States produces anodes at on-site facilities.

In addition to our primary aluminum assets, we own and operate a carbon anode production facility in Vlissingen, Netherlands, through our wholly-owned subsidiary, Century Aluminum Vlissingen B.V.

The Vlissingen facility has an annual production capacity of approximately 161,000 tonnes of carbon anodes.

It primarily supplies our Grundartangi smelter, fulfilling between 93% and 98% of Grundartangi’s carbon anode requirements at current production levels.

Bauxite Mining and Alumina Refining Facility

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Refer to Note 1.

Acquisition of Jamalco for further information.

Summary of Sign ificant Accounti n g Policie s , Note 2.

Acquisition of Jamalco , Note 22.

Restatement of Previously Issued Financial Statements , and Note 23.

Quarterly Financial Data (Unaudited and Restated) for further information.

New Smelter Project

On January 26, 2026, we announced that we had entered into a joint development agreement with 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.

production of primary aluminum.

Construction of the project is expected to start by the end of 2026, subject to the completion of detailed engineering work and completion of negotiations with Public Service Company of Oklahoma on a competitive long-term power supply agreement.

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 (the “Data Center Minority Interest”).

A large portion of the proceeds is 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.

Pricing for primary aluminum products is typically comprised of three components:

(i) the base commodity price, which is based on quoted prices on the LME, plus (ii) any regional premium (e.g., the Midwest premium for metal sold in the United States and the European Duty Paid premium for metal sold into Europe) plus (iii) any value-added product premium.

(i) the base commodity price, which is based on quoted prices on the LME, plus (ii) any regional premium (i.e., the Midwest premium for metal sold in the United States and the European Duty Paid premium for metal sold into Europe) plus (iii) any value-added product premium.

Our operating results are highly sensitive to changes in the LME price of primary aluminum and the amount of regional premiums and value-added product premiums.

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Glencore also purchased 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 also entered into agreements with Glencore pursua nt to which we sell certain amounts of alumina at market-based prices.

Glencore beneficially owns 42.9% of our outstanding common stock (45.8% on a fully diluted basis).

We have also entered into agreements with Glencore pursuant to which we sell certain amounts of alumina at market-based prices.

Glencore beneficially owns 36.4% of our outstanding common stock.

Related Party Transactions to the consolidated financial statements included herein for additional information concerning our relationship with Glencore.

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For the year ended December 31, 2025, approximately 320,000 tonnes, or 31% of Jamalco's alumina production, was sold to our aluminum smelters.

For the period from May 2, 2023 to December 31, 2023 approximately 287,000 tonnes, or 42% of Jamalco's alumina production was sold to Grundartangi.

Our historical financial statements for periods prior to May 2, 2023 do not include the results of Jamalco.

While Century may enter into other purchases of alumina as market conditions change, a summary of our principal alumina supply agreements is provided below:

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Facility Supplier Term Pricing

Grundartangi Landsvirkjun Through 2026 - 2036 Variable rate based on (i) the LME price for primary aluminum (~70%) or (ii) a fixed rate plus an LME-linked component from 2024 - 2026

Grundartangi Landsvirkjun,

Orkuveita Reykjavíkur ("OR"),

HS Orka hf ("HS")

Hawesville Kenergy Corporation ("Kenergy") Through May 31, 2028

Variable rate based on market prices

HS Orka hf ("HS") Through 2026 - 2036 Variable rate based on (i) the LME price for primary aluminum (~70%) or (ii) a fixed rate plus an LME-linked component from 2026 - 2036

Sebree Kenergy Through May 31, 2028

Variable rate based on market prices

Holly Santee Cooper Through December 31, 2026 Service-based rates

Holly South Carolina Public Service Authority (“Santee Cooper”) Through December 31, 2031 Service-based rates

Electrical power represents one of the largest components of our Cost of goods sold.

From time to time, we may enter into forward contracts or other hedging arrangements to mitigate our electrical power or natural gas price risk.

The paragraphs below summarize the sources of power and the long-term power arrangements for each of our operations.

Grundartangi.

Power is currently supplied to Grundartangi from hydroelectric and geothermal sources under long-term power purchase agreements with three separate power suppliers - HS, Landsvirkjun and 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 rates with an additional variable rate linked to the LME.

Grundartangi also has a separate 25 MW power purchase agreement with Landsvirkjun at LME-based variable rate.

Historically, all of the power supplied to Grundartangi has been delivered at prices indexed to the price of primary aluminum.

Each power purchase agreement contains take-or-pay obligations with respect to a significant percentage of the total committed and available power under such agreement.

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

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.

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.

CASC has a power supply agreement with Santee Cooper that has an effective term through December 2026.

Under this power supply agreement, 100% of Mt.

Holly’s electrical power requirements are supplied from Santee Cooper’s generation at service-based rates.

The contract provides sufficient power to allow Mt.

Holly to operate at its current production capacity, as well as an option to take additional power to support any future restart of the remaining 25% of production capacity.

Commitments and Contingencies to the consolidated financial statements included herein for additional information concerning our power arrangements.

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We continue to make progress in enhancing our internal performance management and talent management systems in an effort to continue to recognize and promote outstanding employees.

We have worked to streamline the process for our employees and ensure they have the opportunity to provide input as part of the review process.

We have worked to streamline

the process for our employees and ensure they have the opportunity to provide input as part of the review process.

We attend recruiting events at local colleges and institutes in our communities and offer educational opportunities to our employees to help them develop additional skills and knowledge and continue the process of developing leaders within Century's ranks.

Labor Agreements

The bargaining unit employees at our Grundartangi, Vlissingen, Hawesville, Sebree and Jamalco facilities are represented by labor unions, representing 59% of our total workforce.

The bargaining unit employees at our Grundartangi, Vlissingen, Sebree and Jamalco facilities are represented by labor unions, representing 55% of our total workforce.

Our employees at Mt.

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Through April 1, 2026

(terminated February 13, 2026)

Sebree USW Through October 28, 2028

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Through December 31, 2023 (1)

Approximately 86% of Grundartangi’s workforce 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.

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 39% of our U.S.

based workforce 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.

Approximately 61% 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 are effective through December 31, 2023.

(1) 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.

Commitments and Contingencies to the consolidated financial statements included herein for additional information concerning our labor agreements.

The market for primary aluminum is global, and demand for aluminum varies widely from region to region.

We compete with aluminum producers domestically and internationally, as well as with producers of alternative materials such as steel, copper, carbon fiber, composites, plastic and glass, each of which may be substituted for aluminum in certain applications.

Our competitive position depends, in part, on the availability of electricity, alumina and our other key raw materials to our operations at competitive prices.

Our competitive position depends, in part, on the availability at competitive prices of electricity, alumina and other raw materials key to our operations.

We face global competition from companies who may have access to these key production costs at lower prices, and they may also receive various subsidies from local, state and federal governments.

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Holly (bringing its operations to 75% of Mt.

Holly's maximum production capacity) and can restart another 58,000 tonnes of production capacity in the future provided we are able to obtain sufficient energy at competitive rates.

In 2024, Century completed construction of the Grundartangi Casthouse Project.

The new value-added casthouse can produce up to 150,000 tonnes of billet and 120,000 tonnes of primary foundry alloys, in each case from existing Grundartangi production.

Holly's maximum production capacity).

In August 2025, we began a project to restore the remaining curtailed capacity at Mt.

We expect to achieve full production by June 2026.

Since our purchase of the Vlissingen facility, we have completed a variety of expansion projects and efficiency programs in order to more than double its production capacity.

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We continue to pursue additional internal growth opportunities to maximize efficiencies and improve overall performance.

Additionally, with our acquisition of a 55% interest in Jamalco, we secured a predictable, long-term supply of alumina, our most critical raw material, and achieved increased transparency and control of our supply chain.

Additionally, with our acquisition of a 55% interest in Jamalco, we secured a long-term supply of alumina, our most critical raw material, and achieved increased transparency and control of our supply chain.

Our vertical integration with Jamalco allows us to integrate our aluminum smelting operations with this critical upstream supply of bauxite and alumina to create a more balanced and robust operational footprint, resulting in an organization that is better positioned to deliver strong performance through industry cycles.

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For example, the European Union imposes import tariffs on primary aluminum from producers outside the European Economic Area (the "EEA"), which includes Iceland, and the U.S.

currently imposes a 10% tariff on certain primary aluminum imports into the United States, which is expected to increase to 25% effective March 12, 2025.

currently imposes a 50% tariff on certain primary aluminum imports into the United States.

and Icelandic businesses currently access these respective markets duty-free which provides us with an advantage over our competitors who sell into these markets under these tariff regimes.

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In addition, some of our past manufacturing activities or those of our predecessors have resulted in environmental consequences that require remedial measures.

Under certain environmental laws, which may impose liability regardless of fault, we may be liable for the costs of remediation of contaminated property, including our current and formerly owned or operated properties or adjacent areas, or for the amelioration of damage to natural resources.

the amelioration of damage to natural resources.

We believe, based on currently available information, that compliance with existing laws and regulations has not had a material adverse effect upon our capital expenditures, earnings and our competitive position.

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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 1. Business