Sec Form 4 Filing - GLENCORE INTERNATIONAL AG @ CENTURY ALUMINUM CO - 2020-12-29

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

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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) 12/29/2020 (Street) BAAR, V8CH-6340 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

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 Cash Settled Total Return Swap ( 1 ) ( 2 ) ( 4 ) 12/29/2020( 4 ) X/K 1 ( 1 )( 2 )( 4 ) ( 1 )( 2 )( 4 ) Common Stock 4,729,302 ( 1 ) ( 2 ) ( 1 ) ( 2 ) ( 3 ) ( 4 ) 0 ( 1 ) ( 2 ) ( 4 ) D ( 1 ) ( 5 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other GLENCORE INTERNATIONAL AG BAARERMATTSTRASSE 3 P.O. BOX 1363 BAAR, V8CH-6340 X Glencore plc BAARERMATTSTRASSE 3 P.O. BOX 1363 BAAR, V8CH-6340 X Signatures GLENCORE INTERNATIONAL AG: By: /s/ John Burton; Name: John Burton; Title: Director 12/31/2020 Signature of Reporting Person Date GLENCORE INTERNATIONAL AG: By: /s/ Martin Haering; Name: Martin Haering; Title: Officer 12/31/2020 Signature of Reporting Person Date GLENCORE PLC: By: /s/ John Burton; Name: John Burton; Title: Company Secretary 12/31/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Glencore International AG ("Glencore International"), a direct wholly-owned subsidiary of Glencore plc, previously received economic exposure with respect to 4,729,302 shares of common stock pursuant to a cash-settled total return swap (the "Swap") entered into between Glencore International and Citigroup Global Markets Inc. (together with its successors in interest under the Swap, "Citi"), with an initial expiration date of September 17, 2012 (subsequently extended to April 17, 2021). ( 2 )Upon expiration of the Swap, (i) Glencore International would have been obligated to make a cash payment to Citi with respect to any depreciation in the volume weighted average price of the common stock from the $9.71927 per share volume weighted average price calculated during the initial averaging period for the Swap (which ended on September 15, 2010) to the volume weighted average price of the common stock during the final valuation period preceding the expiration of the term of the Swap, or (ii) Citi would have been obligated to make a cash payment to Glencore International with respect to any appreciation in such volume weighted average price based on the above period. ( 3 )Under the terms of the Swap, generally, Glencore International was obligated to pay to Citi certain fees and commissions and Citi was obligated to pay to Glencore International an amount in cash equal to any dividends that would have been paid by the issuer on the Subject Shares. ( 4 )On September 28, 2020 the parties terminated the Swap, and a net settlement amount of $679,865 (equal to the difference between (i) a final valuation amount based on the volume weighted average price of the common stock during a final valuation period between the termination date and December 29, 2020, and (ii) the original valuation amount equal to the per share initial reference price of $9.71927 multiplied by the 4,729,302 shares referenced by the Swap), became due from Glencore International to Citi. ( 5 )The Swap was held directly by Glencore International, and may be deemed to have been beneficially owned indirectly by Glencore plc. The Swap did not give the reporting persons direct or indirect voting, investment or dispositive control over any securities of the issuer, and accordingly, the reporting persons disclaim any beneficial ownership in the shares of common stock referenced by the swaps.

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).

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