Business Description

Overview Century Aluminum Company is a global producer of primary aluminum and operates aluminum reduction facilities, or "smelters," in the United States and Iceland. Aluminum is an internationally traded commodity, and its price is effectively determined on the London Metal Exchange (the "LME"), plus applicable regional and value-added product premiums. Our smelters produce standard-grade and value-added primary aluminum products. 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. 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"). The remaining 45% interest in Jamalco is indirectly owned by the Government of Jamaica. Century's share of Jamalco's production capacity is approximately 770,000 tpy. We also own a carbon anode production facility located in the Netherlands ("Vlissingen"). Carbon anodes are consumed in the production of primary aluminum. Vlissingen supplies carbon anodes to our aluminum smelter in Grundartangi, Iceland. Each of our aluminum smelters in the United States produces anodes at on-site facilities. At Century, we aim to provide innovative and reliable aluminum products to our customers, a safe and sustainable workplace for our people and the communities in which we operate, and a compelling value proposition for our stockholders. We seek to operate our businesses in a responsible manner by balancing the twin priorities of (i) maintaining a strong balance sheet across commodity cycles and (ii) making investments to lower our cost structure, expand our production capacity, and increase our competitiveness. Century has invested significant capital in recent years to increase production and grow our product portfolio to include more value-added aluminum products to better serve our customers in the U.S. and Europe. We believe that our focus on lowering costs and decommoditizing our product line will enable us to deliver profitable long-term growth and differentiate us from overseas competitors with longer supply lines into the markets we serve. We conduct our business with a focus on sustainability, including the health and safety of our people and the communities in which we operate. 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 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. 1 Table of Contents Primary Aluminum Facilities Overview of Facilities 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"). Our primary aluminum smelters and their respective primary aluminum capacities are shown in the following table: Facility Ownership Percentage Operational Annual Production Capacity (tpy) (1) Actual 2025 Annual Production (tpy) Grundartangi, Iceland 100% 1998 320,000 260,000 Sebree, Kentucky, USA 100% 1973 220,000 217,000 Mt.…