<SEC-DOCUMENT>0001181431-12-050550.txt : 20120914
<SEC-HEADER>0001181431-12-050550.hdr.sgml : 20120914
<ACCEPTANCE-DATETIME>20120914161356
ACCESSION NUMBER:		0001181431-12-050550
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20120912
FILED AS OF DATE:		20120914
DATE AS OF CHANGE:		20120914

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MFS HIGH YIELD MUNICIPAL TRUST
		CENTRAL INDEX KEY:			0000809844
		IRS NUMBER:				042950868
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1130

	BUSINESS ADDRESS:	
		STREET 1:		500 BOYLSTON ST
		STREET 2:		20TH FL LEGAL DEPT.
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6179545000

	MAIL ADDRESS:	
		STREET 1:		500 BOYLSTON ST
		STREET 2:		20TH FL LEGAL DEPT
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	COLONIAL MUNICIPAL INCOME TRUST
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CITIGROUP INC
		CENTRAL INDEX KEY:			0000831001
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-04992
		FILM NUMBER:		121092812

	BUSINESS ADDRESS:	
		STREET 1:		399 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10043
		BUSINESS PHONE:		2125591000

	MAIL ADDRESS:	
		STREET 1:		399 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10043

	FORMER NAME:	
		FORMER CONFORMED NAME:	TRAVELERS GROUP INC
		DATE OF NAME CHANGE:	19950519

	FORMER NAME:	
		FORMER CONFORMED NAME:	TRAVELERS INC
		DATE OF NAME CHANGE:	19940103

	FORMER NAME:	
		FORMER CONFORMED NAME:	PRIMERICA CORP /NEW/
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd356091.xml
<DESCRIPTION>CMU FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-09-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000809844</issuerCik>
        <issuerName>MFS HIGH YIELD MUNICIPAL TRUST</issuerName>
        <issuerTradingSymbol>CMU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000831001</rptOwnerCik>
            <rptOwnerName>CITIGROUP INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>399 PARK AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></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>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Auction Rate Preferred</value>
            </securityTitle>
            <transactionDate>
                <value>2012-09-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1315</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23750</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Subsidiary</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Variable Rate Municipal Term Preferred Shares Series 2016/9</value>
            </securityTitle>
            <transactionDate>
                <value>2012-09-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2844</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2844</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Subsidiary</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These Auction Rate Preferred Shares were purchased by the issuer in connection with its cash tender offer to purchase up to 100% of its outstanding auction rate preferred shares which expired on September 7, 2012.</footnote>
        <footnote id="F2">These Auction Rate Preferred Shares are beneficially owned by Citigroup Global Markets Inc. (&quot;CGMI&quot;). Citigroup Financial Products Inc. (&quot;CFP&quot;) is the sole stockholder of CGMI. Citigroup Global Markets Holdings Inc. (&quot;CGMH&quot;) is the sole stockholder of CFP. Citigroup Inc. is the sole stockholder of CGMH.</footnote>
        <footnote id="F3">These Variable Rate Municipal Term Preferred Shares are beneficially owned by Citibank, N.A. (&quot;Citibank&quot;). Citicorp is the sole stockholder of Citibank. Citigroup Inc. is the sole stockholder of Citicorp.</footnote>
    </footnotes>

    <remarks>The Auction Rate Preferred Shares reported herein represent the Reporting Person's combined holdings in multiple series of auction preferred securities of the issuer which are treated herein as one class of securities consistent with the Reporting Person's prior Section 16 filings made in respect of the issuer.</remarks>

    <ownerSignature>
        <signatureName>Citigroup Inc., By: /s/ Ali L. Karshan, Assistant Secretary</signatureName>
        <signatureDate>2012-09-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
