<SEC-DOCUMENT>0001104659-20-140962.txt : 20201231
<SEC-HEADER>0001104659-20-140962.hdr.sgml : 20201231
<ACCEPTANCE-DATETIME>20201231160120
ACCESSION NUMBER:		0001104659-20-140962
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201229
FILED AS OF DATE:		20201231
DATE AS OF CHANGE:		20201231

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GLENCORE INTERNATIONAL AG
		CENTRAL INDEX KEY:			0001032383

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34474
		FILM NUMBER:		201428864

	BUSINESS ADDRESS:	
		STREET 1:		BAARERMATTSTRASSE 3
		STREET 2:		P O BOX 555 CH 6341 BAAR
		CITY:			SWITZERLAND
		BUSINESS PHONE:		4142227722

	MAIL ADDRESS:	
		STREET 1:		BAARERMATTSTRASSE 3
		STREET 2:		P O BOX 555 CH 6341 BAAR
		CITY:			SWITZERLAND

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Glencore plc
		CENTRAL INDEX KEY:			0001521365
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 8880 [8880]
		STATE OF INCORPORATION:			Y9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34474
		FILM NUMBER:		201428865

	BUSINESS ADDRESS:	
		STREET 1:		BAARERMATTSTRASSE 3
		CITY:			BAAR
		STATE:			V8
		ZIP:			CH-6341
		BUSINESS PHONE:		41 41 709 2000

	MAIL ADDRESS:	
		STREET 1:		BAARERMATTSTRASSE 3
		CITY:			BAAR
		STATE:			V8
		ZIP:			CH-6341

	FORMER NAME:	
		FORMER CONFORMED NAME:	Glencore Xstrata plc
		DATE OF NAME CHANGE:	20130606

	FORMER NAME:	
		FORMER CONFORMED NAME:	GLENCORE INTERNATIONAL PLC
		DATE OF NAME CHANGE:	20110520

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CENTURY ALUMINUM CO
		CENTRAL INDEX KEY:			0000949157
		STANDARD INDUSTRIAL CLASSIFICATION:	PRIMARY PRODUCTION OF ALUMINUM [3334]
		IRS NUMBER:				133070826
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1 SOUTH WACKER DRIVE
		STREET 2:		SUITE 1000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3126963101

	MAIL ADDRESS:	
		STREET 1:		1 SOUTH WACKER DRIVE
		STREET 2:		SUITE 1000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2039686-1_4.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-12-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000949157</issuerCik>
        <issuerName>CENTURY ALUMINUM CO</issuerName>
        <issuerTradingSymbol>CENX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001032383</rptOwnerCik>
            <rptOwnerName>GLENCORE INTERNATIONAL AG</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BAARERMATTSTRASSE 3</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 1363</rptOwnerStreet2>
            <rptOwnerCity>BAAR</rptOwnerCity>
            <rptOwnerState>V8</rptOwnerState>
            <rptOwnerZipCode>CH-6340</rptOwnerZipCode>
            <rptOwnerStateDescription>SWITZERLAND</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001521365</rptOwnerCik>
            <rptOwnerName>Glencore plc</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BAARERMATTSTRASSE 3</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 1363</rptOwnerStreet2>
            <rptOwnerCity>BAAR</rptOwnerCity>
            <rptOwnerState>V8</rptOwnerState>
            <rptOwnerZipCode>CH-6340</rptOwnerZipCode>
            <rptOwnerStateDescription>SWITZERLAND</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Cash Settled Total Return Swap</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-12-29</value>
                <footnoteId id="F4"/>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>X</transactionCode>
                <equitySwapInvolved>1</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4729302</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Glencore International AG (&quot;Glencore International&quot;), 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 &quot;Swap&quot;) entered into between Glencore International and Citigroup Global Markets Inc. (together with its successors in interest under the Swap, &quot;Citi&quot;), with an initial expiration date of September 17, 2012 (subsequently extended to April 17, 2021).</footnote>
        <footnote id="F2">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.</footnote>
        <footnote id="F3">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.</footnote>
        <footnote id="F4">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.</footnote>
        <footnote id="F5">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.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>GLENCORE INTERNATIONAL AG: By: /s/ John Burton; Name: John Burton; Title: Director</signatureName>
        <signatureDate>2020-12-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>GLENCORE INTERNATIONAL AG: By: /s/ Martin Haering; Name: Martin Haering; Title: Officer</signatureName>
        <signatureDate>2020-12-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>GLENCORE PLC: By: /s/ John Burton; Name: John Burton; Title: Company Secretary</signatureName>
        <signatureDate>2020-12-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
