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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001362118-07-000019.txt : 20070308
<SEC-HEADER>0001362118-07-000019.hdr.sgml : 20070308
<ACCEPTANCE-DATETIME>20070308160304
ACCESSION NUMBER:		0001362118-07-000019
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070306
FILED AS OF DATE:		20070308
DATE AS OF CHANGE:		20070308

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NATIONAL MERCANTILE BANCORP
		CENTRAL INDEX KEY:			0000714801
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				953819685
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1840 CENTURY PARK EAST
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90067
		BUSINESS PHONE:		3102772265

	MAIL ADDRESS:	
		STREET 1:		1840 CENTURY PARK EAST
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90067

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			POHLAD WILLIAM M
		CENTRAL INDEX KEY:			0001061271
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13015
		FILM NUMBER:		07681011

	BUSINESS ADDRESS:	
		STREET 1:		60 SOUTH SIXTH ST
		STREET 2:		STE 3800
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55402
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-03-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000714801</issuerCik>
        <issuerName>NATIONAL MERCANTILE BANCORP</issuerName>
        <issuerTradingSymbol>MBLA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001061271</rptOwnerCik>
            <rptOwnerName>POHLAD WILLIAM M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>60 SOUTH 6TH STREET, SUITE 4050</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MINNEAPOLIS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55402</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <transactionDate>
                <value>2007-03-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4167</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.645</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>844777</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person is a party to a Securities Purchase and Option Agreement dated December 15, 2006 by and among David Brown, James O. Pohlad, Robert C. Pohlad and William M. Pohlad (&quot;Brown Agreement&quot;), by which the reporting person is required to purchase certain shares of common stock as more fully described therein.  A copy of the Brown Agreement can be found as an exhibit to the reporting persons's Schedule 13D, as amended.</footnote>
        <footnote id="F2">The reporting person is a party to a Securities Purchase and Option Agreement dated December 19, 2005 by and among Scott A. Montgomery, James O. Pohlad, Robert C. Pohlad and William M. Pohlad (&quot;Montgomery Agreement&quot;) by which the reporting person is required to purchase certain shares of common stock as more fully described therein.  A copy of the Montgomery Agreement can be found as an exhibit to the reporting person's Schedule 13D, as amended.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Jay L. Kim, Attorney-in-Fact for William M. Pohlad</signatureName>
        <signatureDate>2007-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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