144 0001032383 XXXXXXXX LIVE 0000949157 CENTURY ALUMINUM CO 001-34474 One South Wacker Drive, Suite 1000 Chicago IL 60606 312-696-3101 Glencore International AG 10% Stockholder Common Stock(1)(2) Citigroup Global Markets Inc

388 Greenwich St. 4th Floor Trading New York NY 10013

6315245 51.75 98969007 03/04/2026 NASDAQ Common Stock 12/15/2022 See Note (3) See Note (3) N 27500000 12/15/2022 See Note (3) Y (1) Aggregate Market Value of shares based on a share price of $51.75 on March 4, 2026. (2) Number of Shares or Other Units Outstanding is based on information provided by the Issuer in its Current Report on Form 10-K filed with the SEC on March 3, 2026. (3) Securities to be sold were acquired via a transfer to Glencore International AG by Givolon Limited on December 15, 2022 for no consideration in connection with the termination of a 2017 financing and related pledge among Glencore AG, Ryfold Limited and Givolon Limited. 03/04/2026 /s/ John Burton