1 unchanged sentence
Rule 10b5-1 Trading Plans
−Removed: On August 20, 2025 , the Company’s President, Chief Executive Officer and Director , Jesse E.
−Removed: Gary , adopted a pre-arranged trading plan intended to satisfy the conditions of Rule 10b5-1(c)(1) under the Exchange Act (the “10b5-1 Plan”).
−Removed: The 10b5-1 Plan provides for the potential sale of an aggregate of up to 300,000 shares of the Company’s common stock.
−Removed: The first date that sales of any shares are permitted to be sold under the 10b5-1 Plan is January 2026, and subsequent sales may occur from time to time until the 10b5-1 Plan’s expiration on January 2027 , or earlier if all transactions are completed prior to such date or otherwise terminated.
−Removed: Other than as described above, no other director or “officer” (as defined in Rule 16a-1(f) promulgated under the Exchange Act) adopted , modified, or terminated a “Rule 10b5-1 trading arrangement” or a “non-Rule 10b5-1 trading arrangement” (as such terms are defined under Item 408 of Regulation S-K) during the three months ended September 30, 2025.
+Added: During the quarter ended March 31, 2026, none of the Company's directors or executive officers adopted or terminated any contract, instruction or written plan for the purchase or sale of Company securities that was intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) or any "non-Rule 10b5-1 trading arrangement" as defined in Item 408 of Regulation S-K.
Exhibit Number Description of Exhibit Incorporated by Reference Filed Herewith
Form File No.
+Added: Agreement of Purchase and Sale, dated February 2, 2026, by and between the Century Aluminum of Kentucky General Partnership and Justified DataPower LLC
+Added: 8-K 001-34474 February 2, 2026
Rule 13a-14(a)/15d-14(a) Certification of the Chief Executive Officer
11 unchanged sentences
Century Aluminum Company
−Removed: November 6, 2025 By:
+Added: May 7, 2026 By:
/s/ PETER TRPKOVSKI
Peter Trpkovski
−Removed: Executive Vice President, Chief Financial Officer and Treasurer
+Added: Executive Vice President, Chief Financial Officer
(Principal Financial Officer)
−Removed: November 6, 2025 By:
+Added: May 7, 2026 By:
/s/ ROBERT HOFFMAN
3 unchanged sentences
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.