<SEC-DOCUMENT>0000921895-16-004791.txt : 20160602
<SEC-HEADER>0000921895-16-004791.hdr.sgml : 20160602
<ACCEPTANCE-DATETIME>20160602090127
ACCESSION NUMBER:		0000921895-16-004791
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20160531
FILED AS OF DATE:		20160602
DATE AS OF CHANGE:		20160602

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX GP, LLC
		CENTRAL INDEX KEY:			0001654852
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691229

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVE.
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVE.
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex GP, LLC
		DATE OF NAME CHANGE:	20151005

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX Special Opportunities GP III, LLC
		CENTRAL INDEX KEY:			0001676049
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691230

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		(212) 451-2282

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX Special Opportunities Fund III, LP
		CENTRAL INDEX KEY:			0001619126
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691231

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex Special Opportunities Fund III, LP
		DATE OF NAME CHANGE:	20140910

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX Opportunities Fund, LP Series Two
		CENTRAL INDEX KEY:			0001659404
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691232

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVENUE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVENUE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex Opportunities Fund, LP Series Two
		DATE OF NAME CHANGE:	20151125

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex Opportuniteis Fund, LP Series Two
		DATE OF NAME CHANGE:	20151125

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX Opportunities Fund, LP Series One
		CENTRAL INDEX KEY:			0001606750
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691233

	BUSINESS ADDRESS:	
		STREET 1:		C/O VERTEX CAPITAL ADVISORS, LLC
		STREET 2:		826 THIRD AVENUE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		C/O VERTEX CAPITAL ADVISORS, LLC
		STREET 2:		826 THIRD AVENUE, 33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	VIEX Opportunities Fund, LP
		DATE OF NAME CHANGE:	20151228

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex Opportunities Fund, LP
		DATE OF NAME CHANGE:	20140429

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Singer Eric
		CENTRAL INDEX KEY:			0001443284

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691234

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VIEX Capital Advisors, LLC
		CENTRAL INDEX KEY:			0001619125
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13449
		FILM NUMBER:		161691228

	BUSINESS ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-752-5750

	MAIL ADDRESS:	
		STREET 1:		825 THIRD AVENUE
		STREET 2:		33RD FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	Vertex Capital Advisors, LLC
		DATE OF NAME CHANGE:	20140910

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			QUANTUM CORP /DE/
		CENTRAL INDEX KEY:			0000709283
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER STORAGE DEVICES [3572]
		IRS NUMBER:				942665054
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		224 AIRPORT PARKWAY
		STREET 2:		SUITE 300
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
		BUSINESS PHONE:		408 944 4000

	MAIL ADDRESS:	
		STREET 1:		224 AIRPORT PARKWAY
		STREET 2:		SUITE 300
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95110
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>form310114016_06022016.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2016-05-31</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000709283</issuerCik>
        <issuerName>QUANTUM CORP /DE/</issuerName>
        <issuerTradingSymbol>QTM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001443284</rptOwnerCik>
            <rptOwnerName>Singer Eric</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001606750</rptOwnerCik>
            <rptOwnerName>VIEX Opportunities Fund, LP Series One</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001659404</rptOwnerCik>
            <rptOwnerName>VIEX Opportunities Fund, LP Series Two</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001619126</rptOwnerCik>
            <rptOwnerName>VIEX Special Opportunities Fund III, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001676049</rptOwnerCik>
            <rptOwnerName>VIEX Special Opportunities GP III, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001654852</rptOwnerCik>
            <rptOwnerName>VIEX GP, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001619125</rptOwnerCik>
            <rptOwnerName>VIEX Capital Advisors, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>825 THIRD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>33RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, $0.01 par value</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7407865</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By: VIEX Opportunities Fund, LP - Series One</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, $0.01 par value</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1413191</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By: VIEX Opportunities Fund, LP - Series Two</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, $0.01 par value</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20710666</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By: VIEX Special Opportunities Fund III, LP</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This Form 3 is filed jointly by VIEX Opportunities Fund, LP - Series One (&quot;Series One&quot;), a series of VIEX Opportunities Fund, LP (&quot;VIEX Opportunities&quot;), a series limited partnership, VIEX Opportunities Fund, LP - Series Two (&quot;Series Two&quot;), a series of VIEX Opportunities, VIEX Special Opportunities Fund III, LP (&quot;VSO III&quot;), VIEX GP, LLC (&quot;VIEX GP&quot;), VIEX Special Opportunities GP III, LLC (&quot;VSO GP III&quot;),  VIEX Capital Advisors, LLC (&quot;VIEX Capital&quot;), and Eric Singer (collectively, the &quot;Reporting Persons&quot;).</footnote>
        <footnote id="F2">The Reporting Persons are filing this report because each of the Reporting Persons is a member of a Section 13(d) group, disclosed in a Schedule 13D filed on behalf of the Reporting Persons, as it may be amended, which beneficially owns in the aggregate more than 10% of the Issuer's outstanding shares of Common Stock. Each Reporting Person disclaims beneficial ownership of the shares of Common Stock reported herein except to the extent of his or its pecuniary interest therein, and this report shall not be deemed to be an admission that any Reporting Person is the beneficial owner of such shares of Common Stock for purposes of Section 16 or for any other purpose.</footnote>
        <footnote id="F3">Shares of Common Stock beneficially owned directly by Series One. VIEX GP, as the general partner of Series One, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One. VIEX Capital, as the investment manager of Series One, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series One.</footnote>
        <footnote id="F4">Shares of Common Stock beneficially owned directly by Series Two. VIEX GP, as the general partner of Series Two, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two. VIEX Capital, as the investment manager of Series Two, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two. Mr. Singer, as the managing member of each of VIEX GP and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by Series Two.</footnote>
        <footnote id="F5">Shares of Common Stock beneficially owned directly by VSO III. VSO GP III, as the general partner of VSO III, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III. VIEX Capital, as the investment manager of VSO III, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III. Mr. Singer, as the managing member of each of VSO GP III and VIEX Capital, may be deemed the beneficial owner of the shares of Common Stock beneficially owned by VSO III.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: /s/ Eric Singer</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX Opportunities Fund, LP - Series One; By: VIEX GP, LLC; its general partner; By: /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX Opportunities Fund, LP - Series Two; By: VIEX GP, LLC; its general partner; By: /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX Special Opportunities Fund III, LP; By: VIEX Special Opportunities GP III, LLC; its general partner; By: /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX Special Opportunities GP III, LLC; By /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX GP, LLC; By: /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>VIEX Capital Advisors, LLC; By /s/ Eric Singer, Managing Member</signatureName>
        <signatureDate>2016-06-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
