<SEC-DOCUMENT>0001104659-17-044054.txt : 20170707
<SEC-HEADER>0001104659-17-044054.hdr.sgml : 20170707
<ACCEPTANCE-DATETIME>20170707152642
ACCESSION NUMBER:		0001104659-17-044054
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170315
FILED AS OF DATE:		20170707
DATE AS OF CHANGE:		20170707

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PLUG POWER INC
		CENTRAL INDEX KEY:			0001093691
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRICAL INDUSTRIAL APPARATUS [3620]
		IRS NUMBER:				223672377
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		968 ALBANY-SHAKER ROAD
		CITY:			LATHAM
		STATE:			NY
		ZIP:			12110
		BUSINESS PHONE:		5187827700

	MAIL ADDRESS:	
		STREET 1:		968 ALBANY-SHAKER ROAD
		CITY:			LATHAM
		STATE:			NY
		ZIP:			12110

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FiveT Capital Holdings AG
		CENTRAL INDEX KEY:			0001697007
		STATE OF INCORPORATION:			V8
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34392
		FILM NUMBER:		17955119

	BUSINESS ADDRESS:	
		STREET 1:		C/O RABER TREUHAND GMBH
		STREET 2:		CHURERSTRASSE 98
		CITY:			PFAFFIKON
		STATE:			V8
		ZIP:			8330
		BUSINESS PHONE:		41 43 322 2510

	MAIL ADDRESS:	
		STREET 1:		C/O RABER TREUHAND GMBH
		STREET 2:		CHURERSTRASSE 98
		CITY:			PFAFFIKON
		STATE:			V8
		ZIP:			8330
</SEC-HEADER>
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    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-03-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001093691</issuerCik>
        <issuerName>PLUG POWER INC</issuerName>
        <issuerTradingSymbol>PLUG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001697007</rptOwnerCik>
            <rptOwnerName>FiveT Capital Holdings AG</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RABER TREUHAND GMBH</rptOwnerStreet1>
            <rptOwnerStreet2>CHURERSTRASSE 98</rptOwnerStreet2>
            <rptOwnerCity>PFAFFIKON</rptOwnerCity>
            <rptOwnerState>V8</rptOwnerState>
            <rptOwnerZipCode>8330</rptOwnerZipCode>
            <rptOwnerStateDescription>SWITZERLAND</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
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            <securityTitle>
                <value>Series C Redeemable Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-03-15</value>
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            <transactionCoding>
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            <transactionAmounts>
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                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                    <value>See Footnotes</value>
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                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
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                <transactionShares>
                    <value>4187</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
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                    <value>Common Stock</value>
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            </underlyingSecurity>
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                <directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Series C Redeemable Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-06-15</value>
            </transactionDate>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2081</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
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            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
                    <value>2081</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>930103</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Series C Redeemable Convertible Preferred Stock (the &quot;Series C Preferred Stock&quot;) is convertible at any time at the option of the holder into shares of the Issuer's Common Stock at a conversion price per share of $0.2343, subject to certain adjustments. The Series C Preferred Stock has no expiration date.</footnote>
        <footnote id="F2">On March 15, 2017, FiveT Capital Holdings AG, a limited liability company existing under the laws of Switzerland (&quot;FiveT Capital Holdings&quot;), and Five More Special Situations Fund Limited, a Cayman Islands company (&quot;FiveMore Fund&quot;), acquired 8,455 shares and 4,203 shares, respectively, of the Series C Preferred Stock for payment of a dividend; and on June 15, 2017, FiveT Capital Holdings and FiveMore Fund, acquired 4,187 shares and 2,081 shares, respectively, of the Series C Preferred Stock for payment of a dividend.</footnote>
        <footnote id="F3">These shares are held directly by FiveT Capital Holdings.</footnote>
        <footnote id="F4">These shares are held directly by FiveMore Fund. FiveT Capital AG (&quot;FiveT Capital&quot;), a wholly-owned subsidiary of FiveT Capital Holdings, provides investment advisory services to FiveMore Fund.</footnote>
        <footnote id="F5">Johannes Minho Roth is the Managing Director of FiveT Capital Holdings and has equity interests in each of FiveT Capital Holdings and FiveMore Fund. Mr. Roth is a member of the Board of Directors of the Issuer. Each of FiveT Capital Holdings, FiveT Capital and FiveMore Fund disclaims beneficial ownership of the shares of Series C Preferred Stock, except to the extent of its respective pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of any of such shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ FiveT Capital Holdings AG, by Johannes Minho Roth, Managing Director</signatureName>
        <signatureDate>2017-07-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</SEC-DOCUMENT>
