<SEC-DOCUMENT>0001104659-15-036529.txt : 20150511
<SEC-HEADER>0001104659-15-036529.hdr.sgml : 20150511
<ACCEPTANCE-DATETIME>20150511083343
ACCESSION NUMBER:		0001104659-15-036529
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150507
FILED AS OF DATE:		20150511
DATE AS OF CHANGE:		20150511

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SENIOR HOUSING PROPERTIES TRUST
		CENTRAL INDEX KEY:			0001075415
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				043445278
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		TWO NEWTON PLACE
		STREET 2:		255 WASHINGTON STREET
		CITY:			NEWTON
		STATE:			MA
		ZIP:			02458
		BUSINESS PHONE:		6173323990

	MAIL ADDRESS:	
		STREET 1:		TWO NEWTON PLACE
		STREET 2:		255 WASHINGTON STREET
		CITY:			NEWTON
		STATE:			MA
		ZIP:			02458

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PORTNOY BARRY M
		CENTRAL INDEX KEY:			0001241559

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-15319
		FILM NUMBER:		15848998

	MAIL ADDRESS:	
		STREET 1:		C/O REIT MANAGEMENT & RESEARCH LLC
		STREET 2:		TWO NEWTON PL., 255 WASH. ST., STE. 300
		CITY:			NEWTON
		STATE:			MA
		ZIP:			02458
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-05-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001075415</issuerCik>
        <issuerName>SENIOR HOUSING PROPERTIES TRUST</issuerName>
        <issuerTradingSymbol>NYSE: SNH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001241559</rptOwnerCik>
            <rptOwnerName>PORTNOY BARRY M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O REIT MANAGEMENT &amp; RESEARCH LLC</rptOwnerStreet1>
            <rptOwnerStreet2>TWO NEWTON PL., 255 WASH. ST., STE. 300</rptOwnerStreet2>
            <rptOwnerCity>NEWTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02458</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares of Beneficial Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2015-05-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7560.3</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.53</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>104086.95</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares of Beneficial Interest</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>278899.733</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to the terms of a business management agreement (the &quot;Management Agreement&quot;) between the Issuer and Reit Management &amp; Research LLC (&quot;RMR&quot;), the per share price amount listed above is the average of the closing prices of the Common Shares on the New York Stock Exchange for each trading day during the month of April 2015.</footnote>
        <footnote id="F2">Represents the pecuniary interest of Mr. Portnoy in Common Shares owned by RMR, of which Reit Management &amp; Research Trust (&quot;RMR Trust&quot;) is the sole member. Mr. Portnoy is the Chairman and a director of RMR, and the Chairman, majority beneficial owner and a trustee of RMR Trust. These Common Shares were issued as a portion of the management fee paid by the Issuer to RMR pursuant to the Management Agreement.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Barry M. Portnoy</signatureName>
        <signatureDate>2015-05-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
