Sec Form 4 Filing - GLENCORE INTERNATIONAL AG @ CENTURY ALUMINUM CO - 2023-09-30

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person GLENCORE INTERNATIONAL AG 2. Issuer Name and Ticker or Trading Symbol CENTURY ALUMINUM CO [ CENX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) BAARERMATTSTRASSE 3, P.O. BOX 1363 3. Date of Earliest Transaction (MM/DD/YY) 09/30/2023 (Street) BAAR, V8CH-6341 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 09/30/2023 C 19,790 A 12,155,115 I See Footnote ( 3 ) Common Stock 27,500,000 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Convertible Preferred Stock ( 2 ) 09/30/2023 C 197.9 ( 2 ) ( 2 ) Common Stock 19,790 ( 2 ) 53,508.32 I See Footnote ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other GLENCORE INTERNATIONAL AG BAARERMATTSTRASSE 3 P.O. BOX 1363 BAAR, V8CH-6341 X Glencore AG BAARERMATTSTRASSE 3 P.O. BOX 1363 BAAR, V8CH-6341 X Glencore plc BAARERMATTSTRASSE 3 P.O. BOX 1363 BAAR, V8CH-6341 X Signatures GLENCORE AG By: /s/ Stephan Huber Name: Stephan Huber Title: Director 10/02/2023 Signature of Reporting Person Date GLENCORE AG By: /s/ Martin Haering Name: Martin Haering Title: Director 10/02/2023 Signature of Reporting Person Date GLENCORE INTERNATIONAL AG By: /s/ Martin Haering Name: Martin Haering Title: Officer 10/02/2023 Signature of Reporting Person Date GLENCORE INTERNATIONAL AG By: /s/ Derrick Crowley Name: Derrick Crowley Title: Officer 10/02/2023 Signature of Reporting Person Date GLENCORE PLC By: /s/ John Burton Name: John Burton Title: Company Secretary 10/02/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of Common Stock acquired upon conversion of 197.90 shares of Series A Convertible Preferred Stock on September 30, 2023. ( 2 )Each share of Series A Convertible Preferred Stock is convertible into 100 shares of Common Stock at the times and under the circumstances described in the Certificate of Designation for the Series A Convertible Preferred Stock. The Series A Convertible Preferred Stock has no expiration date. ( 3 )The shares of Common Stock reported in Line 1 of Table I and the shares of Series A Convertible Preferred Stock reported in Table II are held directly by Glencore AG, a direct wholly-owned subsidiary of Glencore International AG, and may be deemed to be indirectly beneficially owned by Glencore International AG. The Common Stock reported on Line 2 of Table I is held directly by Glencore International AG. Glencore International AG is wholly owned by Glencore plc, which may be deemed an indirect beneficial owner of the securities held by Glencore AG and Glencore International AG.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.