<SEC-DOCUMENT>0001562180-22-001782.txt : 20220223
<SEC-HEADER>0001562180-22-001782.hdr.sgml : 20220223
<ACCEPTANCE-DATETIME>20220223164946
ACCESSION NUMBER:		0001562180-22-001782
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220223
FILED AS OF DATE:		20220223
DATE AS OF CHANGE:		20220223

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sperber Julie K.
		CENTRAL INDEX KEY:			0001601481

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10816
		FILM NUMBER:		22664656

	MAIL ADDRESS:	
		STREET 1:		MGIC INVESTMENT CORPORATION
		STREET 2:		250 EAST KILBOURN AVENUE
		CITY:			MILWAUKEE
		STATE:			WI
		ZIP:			53202

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MGIC INVESTMENT CORP
		CENTRAL INDEX KEY:			0000876437
		STANDARD INDUSTRIAL CLASSIFICATION:	SURETY INSURANCE [6351]
		IRS NUMBER:				391486475
		STATE OF INCORPORATION:			WI
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		250 EAST KILBOURN AVENUE
		CITY:			MILWAUKEE
		STATE:			WI
		ZIP:			53202
		BUSINESS PHONE:		4143476480

	MAIL ADDRESS:	
		STREET 1:		250 EAST KILBOURN AVENUE
		CITY:			MILWAUKEE
		STATE:			WI
		ZIP:			53202
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primarydocument.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-02-23</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000876437</issuerCik>
        <issuerName>MGIC INVESTMENT CORP</issuerName>
        <issuerTradingSymbol>MTG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001601481</rptOwnerCik>
            <rptOwnerName>Sperber Julie K.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MGIC INVESTMENT CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>250 EAST KILBOURN AVENUE</rptOwnerStreet2>
            <rptOwnerCity>MILWAUKEE</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>53202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>VP-Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-02-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1948.00</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>75332.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of Issuer common stock to be issued under a restricted stock unit award granted to the Reporting Person on March 1, 2021.  The award is subject to performance-vesting restrictions based on growth in adjusted book value per share. Performance with respect to the shares reported in Column 4 has been approved by the appropriate committee of  Issuer's Board.  Provided continued employment, the shares will be issued to the Reporting Person on March 10, 2022.</footnote>
        <footnote id="F2">These RSUs were awarded to the reporting person pursuant to the Issuer's 2020 Omnibus Incentive Plan and no price was paid by the reporting person for them.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Martha F. Tsuchihashi, Attorney-in-Fact</signatureName>
        <signatureDate>2022-02-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
