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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 XOxl480dghFEGxUtPvFbTg==

<SEC-DOCUMENT>0001140361-10-032832.txt : 20100811
<SEC-HEADER>0001140361-10-032832.hdr.sgml : 20100811
<ACCEPTANCE-DATETIME>20100811165651
ACCESSION NUMBER:		0001140361-10-032832
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100809
FILED AS OF DATE:		20100811
DATE AS OF CHANGE:		20100811

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hendry Gregory L
		CENTRAL INDEX KEY:			0001486334

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34416
		FILM NUMBER:		101008576

	MAIL ADDRESS:	
		STREET 1:		3300 LAKE AVENUE
		CITY:			ALTADENA
		STATE:			CA
		ZIP:			91001

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PennyMac Mortgage Investment Trust
		CENTRAL INDEX KEY:			0001464423
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				270186273
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		27001 AGOURA ROAD
		STREET 2:		THIRD FLOOR
		CITY:			CALABASAS
		STATE:			CA
		ZIP:			91301
		BUSINESS PHONE:		(818) 224-7442

	MAIL ADDRESS:	
		STREET 1:		27001 AGOURA ROAD
		STREET 2:		THIRD FLOOR
		CITY:			CALABASAS
		STATE:			CA
		ZIP:			91301
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001464423</issuerCik>
        <issuerName>PennyMac Mortgage Investment Trust</issuerName>
        <issuerTradingSymbol>PMT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001486334</rptOwnerCik>
            <rptOwnerName>Hendry Gregory L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PENNYMAC MORTGAGE INVESTMENT TRUST</rptOwnerStreet1>
            <rptOwnerStreet2>27001 AGOURA ROAD</rptOwnerStreet2>
            <rptOwnerCity>CALABASAS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91301</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares of Beneficial Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>125</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.9912</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1315</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The common shares of beneficial interest were sold in order to pay the estimated tax withholding obligation that resulted from the vesting of 360 restricted share units on August 4, 2010.</footnote>
        <footnote id="F2">The reported amount consists of 1,080 restricted share units and 235 common shares of beneficial interest.  The restricted share units, which were granted to Mr. Hendry upon the completion of the Company's initial public offering on August 4, 2009, vest in three equal annual installments, on August 4, 2011, August 4, 2012 and August 4, 2013, and are to be settled in an equal number of common shares of beneficial interest upon vesting. A total of 360 restricted share units vested on August 4, 2010 and were settled in common shares of beneficial interest, of which 125 were sold as described in the preceding footnote and 235 are included in the reported amount</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Gregory L. Hendry</signatureName>
        <signatureDate>2010-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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