UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF

REGISTERED MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-04992

MFS HIGH YIELD MUNICIPAL TRUST

(Exact name of registrant as specified in charter)

500 Boylston Street, Boston, Massachusetts 02116

(Address of principal executive offices) (Zip code)

Susan S. Newton

Massachusetts Financial Services Company

500 Boylston Street

Boston, Massachusetts 02116

(Name and address of agents for service)

Registrant’s telephone number, including area code: (617) 954-5000

Date of fiscal year end: November 30

Date of reporting period: February 28, 2011

ITEM 1. SCHEDULE OF INVESTMENTS.

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11

Issuer	Shares/Par		Value ($)
Municipal Bonds – 157.4%
Airport & Port Revenue – 4.6%
Dallas Fort Worth, TX, International Airport Rev. Improvement, “B”, AGM, 5%, 2025	$	3,000,000	$	2,990,550
Maryland Economic Development Corp. Rev. (Port America Chesapeake Terminal Project), “B”, 5.75%, 2035		285,000		262,964
Port Authority NY & NJ, Cons Thirty Seventh, AGM, 5.125%, 2030		1,450,000		1,479,537
Port Authority NY & NJ, Special Obligation Rev. (JFK International Air Terminal LLC), 6%, 2036		255,000		248,806
Port Authority NY & NJ, Special Obligation Rev. (JFK International Air Terminal LLC), 6%, 2042		290,000		280,787
			$	5,262,644
General Obligations - General Purpose – 0.4%
Luzerne County, PA, AGM, 6.75%, 2023	$	455,000	$	497,333
General Obligations - Improvement – 0.3%
Guam Government, “A”, 6.75%, 2029	$	140,000	$	147,504
Guam Government, “A”, 7%, 2039		160,000		167,502
			$	315,006
General Obligations - Schools – 2.2%
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2029	$	2,195,000	$	718,316
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2031		275,000		79,555
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2032		280,000		74,659
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2033		560,000		137,362
Irving, TX, Independent School District, Capital Appreciation, “A”, PSF, 0%, 2016		1,000,000		889,920
Los Angeles, CA, Unified School District, “D”, 5%, 2034		165,000		158,057
San Jacinto, TX, Community College District, 5.125%, 2038		430,000		433,363
			$	2,491,232
Healthcare Revenue - Hospitals – 36.8%
Allegheny County, PA, Hospital Development Authority Rev. (University of Pittsburgh Medical Center), “A”, 5.375%, 2029	$	440,000	$	435,670
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5%, 2028		435,000		293,016
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5.375%, 2040		625,000		404,856
Atchison, KS, Hospital Rev. (Atchison Hospital Assn.), “A”, 6.75%, 2030		320,000		283,702
Brunswick, GA, Hospital Authority Rev. (Glynn-Brunswick Memorial Hospital), 5.625%, 2034		170,000		164,516
California Health Facilities Financing Authority Rev. (St. Joseph Health System), “A”, 5.75%, 2039		185,000		177,021
California Health Facilities Financing Authority Rev. (Sutter Health), “A”, 5%, 2042		500,000		420,285
California Health Facilities Financing Authority Rev. (Sutter Health), “B”, 5.875%, 2031		660,000		665,445
California Municipal Finance Authority Rev. (Eisenhower Medical Center), “A”, 5.75%, 2040		40,000		36,329
California Statewide Communities Development Authority Rev. (Catholic Healthcare West), “K”, ASSD GTY, 5.5%, 2041		625,000		602,644
California Statewide Communities Development Authority Rev. (Catholic Healthcare West), “L”, ASSD GTY, 5.25%, 2041		870,000		807,830
California Statewide Communities Development Authority Rev. (Children’s Hospital), 5%, 2047		290,000		220,243
Cullman County, AL, Health Care Authority (Cullman Regional Medical Center), “A”, 6.75%, 2029		60,000		56,159
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2016 (c)		965,000		1,038,099
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2026 (c)		500,000		562,285

1

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Erie County, PA, Hospital Authority Rev. (St. Vincent’s Health), “A”, 7%, 2027	$	410,000	$	399,459
Gage County, NE, Hospital Authority No. 1, Health Care Facilities Rev. (Beatrice Community Hospital & Health Care Center), “B”, 6%, 2025		70,000		67,781
Gage County, NE, Hospital Authority No. 1, Health Care Facilities Rev. (Beatrice Community Hospital & Health Care Center), “B”, 6.5%, 2030		230,000		220,013
Gage County, NE, Hospital Authority No. 1, Health Care Facilities Rev. (Beatrice Community Hospital & Health Care Center), “B”, 6.75%, 2035		195,000		188,001
Garden City, MI, Hospital Finance Authority Rev. (Garden City Hospital), 5%, 2038		500,000		318,370
Harris County, TX, Health Facilities Development Corp., Hospital Rev. (Memorial Hermann Healthcare Systems), “B”, 7.25%, 2035		205,000		222,378
Idaho Health Facilities Authority Rev. (IHC Hospitals, Inc.), ETM, 6.65%, 2021 (c)		2,750,000		3,495,635
Illinois Finance Authority Rev. (Children’s Memorial Hospital), “A”, ASSD GTY, 5.25%, 2047		870,000		795,293
Illinois Finance Authority Rev. (Kewanee Hospital), 5.1%, 2031		400,000		312,564
Illinois Finance Authority Rev. (Provena Health), “A”, 7.75%, 2034		485,000		529,848
Illinois Finance Authority Rev. (Silver Cross Hospital & Medical Centers), 6.875%, 2038		485,000		485,437
Indiana Health & Educational Facilities Finance Authority Rev. (Sisters of St. Francis Health Services, Inc.), “E”, AGM, 5.25%, 2041		660,000		610,249
Indiana Health & Educational Facilities Finance Authority, Hospital Rev. (Clarian Health), “A”, 5%, 2039		1,745,000		1,487,368
Indiana Health & Educational Facilities Finance Authority, Hospital Rev. (Community Foundation of Northwest Indiana), 5.5%, 2037		945,000		830,390
Indiana Health & Educational Financing Authority Rev. (Community Foundation of Northwest Indiana ), “A”, 6%, 2034		425,000		421,855
Johnson City, TN, Health & Educational Facilities Board Hospital Rev. (Mountain States Health Alliance), “A”, 5.5%, 2031		1,120,000		1,023,960
Johnson City, TN, Health & Educational Facilities Board Hospital Rev. (Mountain States Health Alliance), “A”, 5.5%, 2036		410,000		365,404
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.375%, 2024		300,000		309,963
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.625%, 2027		100,000		103,634
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Owensboro Medical Health System), “A”, 6.375%, 2040		570,000		532,517
Lake County, OH, Hospital Facilities Rev. (Lake Hospital Systems, Inc.), 5.625%, 2029		435,000		410,453
Lebanon County, PA, Health Facilities Authority Rev. (Good Samaritan Hospital), 5.9%, 2028		210,000		187,520
Louisiana Public Facilities Authority Hospital Rev. (Lake Charles Memorial Hospital), 6.375%, 2034		880,000		801,548
Louisville & Jefferson County, KY, Metro Government Health Facilities Rev. (Jewish Hospital & St. Mary’s Healthcare), 6.125%, 2037		1,315,000		1,285,702
Louisville & Jefferson County, KY, Metropolitan Government Healthcare Systems Rev. (Norton Healthcare, Inc.), 5.25%, 2036		1,265,000		1,105,952
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2032		60,000		50,240
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2037		60,000		48,991
Maryland Health & Higher Educational Facilities Authority Rev. (Anne Arundel Health System), “A”, 6.75%, 2039		735,000		798,210
Maryland Health & Higher Educational Facilities Authority Rev. (Washington County Hospital), 6%, 2043		120,000		110,608
Massachusetts Health & Educational Facilities Authority Rev. (Boston Medical Center), 5.25%, 2038		1,000,000		823,530
Massachusetts Health & Educational Facilities Authority Rev. (Jordan Hospital), “E”, 6.75%, 2033		250,000		231,508

2

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Massachusetts Health & Educational Facilities Authority Rev. (Milford-Whitinsville Hospital), “C”, 5.25%, 2018	$	500,000	$	468,525
Massachusetts Health & Educational Facilities Authority Rev. (Quincy Medical Center), “A”, 6.5%, 2038		485,000		401,391
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2031		125,000		105,799
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2036		825,000		679,973
New Hampshire Business Finance Authority Rev. (Elliot Hospital Obligated Group), “A”, 6%, 2027		585,000		573,546
New Hampshire Health & Education Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2012 (c)		175,000		189,355
New Hampshire Health & Education Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2032		25,000		24,119
New Hampshire Health & Educational Facilities Authority Rev. (Memorial Hospital at Conway), 5.25%, 2021		530,000		495,232
New Hanover County, NC, Hospital Rev., AGM, 5.125%, 2031		895,000		902,688
New Jersey Health Care Facilities, Financing Authority Rev. (St. Peter’s University Hospital), 5.75%, 2037		545,000		452,230
New Mexico Hospital Equipment Loan Council, Hospital Rev. (Rehoboth McKinley Christian Hospital), “A”, 5%, 2017		285,000		263,887
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.5%, 2030		190,000		202,852
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.25%, 2035		115,000		120,490
Norman, OK, Regional Hospital Authority Rev., 5%, 2027		155,000		129,887
Norman, OK, Regional Hospital Authority Rev., 5.375%, 2029		90,000		76,953
Norman, OK, Regional Hospital Authority Rev., 5.375%, 2036		235,000		188,945
Norman, OK, Regional Hospital Authority Rev., 5.125%, 2037		415,000		318,139
Olympia, WA, Healthcare Facilities Authority Rev. (Catholic Health Initiatives), “D”, 6.375%, 2036		1,095,000		1,161,313
Orange County, FL, Health Facilities Authority Hospital Rev. (Orlando Regional Healthcare), 5.75%, 2012 (c)		150,000		163,220
Palomar Pomerado Health Care District, CA, COP, 6.75%, 2039		1,010,000		1,010,535
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Health System), “A”, 6.625%, 2023		375,000		375,004
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Health System), “A”, 5.5%, 2030		480,000		422,280
Rhode Island Health & Educational Building Corp. Rev., Hospital Financing (Lifespan Obligated Group), “A”, ASSD GTY, 7%, 2039		660,000		711,922
Royal Oak, MI, Hospital Finance Authority Rev. (William Beaumont Hospital), 8.25%, 2039		485,000		549,781
Salida, CO, Hospital District Rev., 5.25%, 2036		734,000		598,416
Scottsdale, AZ, Industrial Development Authority, Hospital Rev. (Scottsdale Healthcare), “C”, ASSD GTY, 5%, 2035		60,000		55,256
Skagit County, WA, Public Hospital District No. 001 Rev. (Skagit Valley Hospital), 5.75%, 2032		90,000		81,319
South Lake County, FL, Hospital District Rev. (South Lake Hospital), 6.375%, 2034		250,000		247,428
South Lake County, FL, Hospital District Rev. (South Lake Hospital), “A”, 6%, 2029		85,000		82,623
South Lake County, FL, Hospital District Rev. (South Lake Hospital), “A”, 6.25%, 2039		125,000		120,826
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.375%, 2015		427,000		428,038
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.5%, 2020		550,000		537,323
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.125%, 2026		500,000		436,675
Sullivan County, TN, Health, Educational & Housing Facilities Board Hospital Rev. (Wellmont Health Systems Project), “C”, 5.25%, 2036		1,085,000		891,664

3

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Sumner County, TN, Health, Educational & Housing Facilities Board Rev. (Sumner Regional Health Systems, Inc.), “A”, 5.5%, 2046 (a)	$	375,000	$	20,625
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.25%, 2032		230,000		183,269
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.375%, 2037		190,000		148,571
Virginia Small Business Financing Authority, Hospital Rev. (Wellmont Health Project), “A”, 5.25%, 2037		470,000		387,026
Washington Health Care Facilities Authority Rev. (Multicare Health Systems), “B”, ASSD GTY, 6%, 2039		440,000		453,495
West Contra Costa, CA, Healthcare District, AMBAC, 5.5%, 2029		105,000		105,752
Wisconsin Health & Educational Facilities Authority Rev. (Aurora Health Care, Inc.), 6.4%, 2033		350,000		354,515
Wisconsin Health & Educational Facilities Authority Rev. (Fort Healthcare, Inc.), 6.1%, 2034		750,000		693,218
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), 5.75%, 2012 (c)		450,000		477,333
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), 5.25%, 2034		935,000		783,483
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), “A”, 5.25%, 2025		390,000		357,396
			$	42,174,798
Healthcare Revenue - Long Term Care – 24.1%
ABAG Finance Authority for Non-Profit Corps., CA, Rev. (Casa de las Campanas), CHCLI, 6%, 2037	$	90,000	$	85,325
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement Systems, Inc.), “A”, 5.9%, 2025		750,000		600,263
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement Systems, Inc.), “A”, 7%, 2033		200,000		166,880
Boston, MA, Industrial Development Financing Authority Rev. (Springhouse, Inc.), 5.875%, 2020		235,000		218,148
Bucks County, PA, Industrial Development Authority Retirement Community Rev. (Ann’s Choice, Inc.), “A”, 6.125%, 2025		500,000		467,450
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2027		90,000		74,305
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2037		120,000		91,211
California Statewide Communities Development Authority Rev. (American Baptist Homes of the West), 6.25%, 2039		215,000		201,707
Capital Projects Finance Authority, FL (Glenridge on Palmer Ranch), “A”, 8%, 2012 (c)		500,000		550,900
Chartiers Valley, PA, Industrial & Commercial Development Authority (Friendship Village), “A”, 5.75%, 2020		1,000,000		999,890
Chartiers Valley, PA, Industrial & Commercial Development Authority Rev. (Asbury Health Center), 6.375%, 2024		1,000,000		937,720
Colorado Health Facilities Authority Rev. (American Housing Foundation, Inc.), 8.5%, 2011 (c)		515,000		543,083
Colorado Health Facilities Authority Rev. (Christian Living Communities Project), “A”, 5.75%, 2037		475,000		394,678
Colorado Health Facilities Authority Rev. (Covenant Retirement Communities, Inc.), 5%, 2035		1,100,000		860,981
Colorado Health Facilities Authority Rev. (Evangelical Lutheran), “A”, 6.125%, 2038		120,000		120,143
Columbus, GA, Housing Authority Rev. (Calvary Community, Inc.), 7%, 2019		370,000		328,382
Cumberland County, PA, Municipal Authority Rev. (Diakon Lutheran Social Ministries), 6.125%, 2029		695,000		698,141
Fulton County, GA, Residential Care Facilities (Canterbury Court), “A”, 6.125%, 2026		500,000		444,965

4

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Hamden, CT, Facility Rev. (Whitney Center Project), “A”, 7.625%, 2030	$	65,000	$	66,700
Hamden, CT, Facility Rev. (Whitney Center Project), “A”, 7.75%, 2043		325,000		331,039
Hawaii Department of Budget & Finance, Special Purpose Rev. (15 Craigside Project), “A”, 9%, 2044		140,000		155,389
Houston, TX, Health Facilities Development Corp. (Buckingham Senior Living Community), “A”, 7%, 2014 (c)		500,000		586,870
Howard County, MD, Retirement Facilities Rev. (Vantage House Corp.), “A”, 5.25%, 2033		200,000		144,048
Illinois Finance Authority Rev. (Evangelical Retirement Homes of Greater Chicago, Inc.), 7.25%, 2045		850,000		818,899
Illinois Finance Authority Rev. (Smith Village), “A”, 6.25%, 2035		1,000,000		819,960
Illinois Health Facilities Authority Rev. (Smith Crossing), “A”, 7%, 2032		525,000		454,881
Indiana Health Facilities Financing Authority Rev. (Hoosier Care, Inc.), “A”, 7.125%, 2034		985,000		852,035
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), 9.25%, 2011 (c)		860,000		909,579
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2018		460,000		432,184
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2028		1,475,000		1,208,232
James City County, VA, Economic Development (WindsorMeade Project), “A”, 5.5%, 2037		440,000		251,456
Kentucky Economic Development Finance Authority Health Facilities Rev. (AHF/Kentucky-Iowa, Inc.), 8%, 2029		353,000		341,580
La Verne, CA, COP (Brethren Hillcrest Homes), “B”, 6.625%, 2025		525,000		500,005
Massachusetts Development Finance Agency Rev. (Adventcare), “A”, 6.75%, 2037		695,000		598,437
Massachusetts Development Finance Agency Rev. (Alliance Health of Brockton, Inc.), “A”, 7.1%, 2032		1,040,000		879,663
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.5%, 2027		185,000		133,083
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.75%, 2035		45,000		30,953
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 5.625%, 2015		190,000		189,573
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 6.9%, 2032		125,000		125,166
Massachusetts Development Finance Agency Rev. (The Groves in Lincoln), “A”, 7.75%, 2039		80,000		79,261
Massachusetts Development Finance Agency Rev. (The Groves in Lincoln), “A”, 7.875%, 2044		115,000		113,577
Massachusetts Industrial Finance Agency Rev. (GF/Massachusetts, Inc.), 8.3%, 2023		725,000		289,377
Metropolitan Government of Nashville & Davidson County, TN, Health & Educational Facilities Board Rev. (Blakeford at Green Hills), 5.65%, 2024		575,000		490,584
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.125%, 2028		150,000		126,483
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.25%, 2035		600,000		490,992
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.75%, 2025		400,000		360,372
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.875%, 2037		300,000		243,222
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2026		500,000		423,300
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2036		500,000		396,275
Norfolk, VA, Redevelopment & Housing Authority Rev. (Fort Norfolk Retirement Community), “A”, 6.125%, 2035		195,000		167,712
Roseville, MN, Elder Care Facilities (Care Institute, Inc.), 7.75%, 2023		1,630,000		1,254,774
Savannah, GA, Economic Development Authority, First Mortgage (Marshes of Skidway), “A”, 7.4%, 2034		350,000		318,248

5

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Shelby County, TN, Health, Educational & Housing Facilities Board Rev. (Germantown Village), “A”, 7.25%, 2034	$	300,000	$	275,301
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2027		280,000		138,292
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2042		260,000		127,083
South Carolina Jobs & Economic Development Authority, Health Facilities Rev. (Wesley Commons), 5.3%, 2036		200,000		146,674
St. John’s County, FL, Industrial Development Authority Rev. (Glenmoor Project), “A”, 5.25%, 2026		500,000		386,480
St. John’s County, FL, Industrial Development Authority Rev. (Presbyterian Retirement), “A”, 6%, 2045		610,000		573,784
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Air Force Village), 6.125%, 2029		550,000		519,849
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Air Force Village), 6.375%, 2044		415,000		383,041
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Stayton at Museum Way), 8.25%, 2044		770,000		738,715
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7%, 2030		130,000		127,538
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7.125%, 2040		195,000		191,318
Westmoreland County, PA, Industrial Development Authority Rev. (Redstone Retirement Community), “A”, 5.875%, 2032		600,000		487,728
Westmoreland County, PA, Industrial Development Retirement Authority Rev. (Redstone Retirement Community), “A”, 5.75%, 2026		1,250,000		1,065,025
Wisconsin Health & Educational Facilities Authority Rev. (All Saints Assisted Living Project), 6%, 2037		180,000		150,689
			$	27,679,598
Healthcare Revenue - Other – 0.5%
Massachusetts Health & Educational Facilities Authority Rev. (Civic Investments, Inc.), “A”, 9%, 2012 (c)	$	550,000	$	619,537
Industrial Revenue - Airlines – 5.8%
Alliance Airport Authority, Inc., TX (American Airlines, Inc.), 5.25%, 2029	$	1,560,000	$	1,076,384
Chicago, IL, O’Hare International Airport Special Facilities Rev. (American Airlines, Inc.), 5.5%, 2030		1,025,000		782,588
Clayton County, GA, Development Authority Special Facilities Rev. (Delta Airlines, Inc.), “A”, 8.75%, 2029		200,000		224,218
Clayton County, GA, Development Authority Special Facilities Rev. (Delta Airlines, Inc.), “B”, 9%, 2035		150,000		159,639
Denver, CO, City & County Airport Rev. (United Airlines), 5.75%, 2032		355,000		310,937
Houston, TX, Airport Systems Rev., Special Facilities (Continental Airlines, Inc.), “E”, 7%, 2029		200,000		199,564
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 6.25%, 2029		935,000		873,795
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 9%, 2033		1,250,000		1,295,813
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.5%, 2016		600,000		613,536
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.625%, 2025		155,000		156,595
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.75%, 2031		385,000		399,384

6

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue - Airlines – continued
New York, NY, City Industrial Development Agency Special Facility Rev. (American Airlines, Inc.), “B”, 8.5%, 2028	$	500,000	$	514,870
			$	6,607,323
Industrial Revenue - Chemicals – 1.5%
Brazos River, TX, Harbor Navigation District (Dow Chemical Co.), “B-2”, 4.95%, 2033	$	400,000	$	368,116
Michigan Strategic Fund Ltd. Obligation Rev. (Dow Chemical Co.), 6.25%, 2014		655,000		707,452
Port of Bay, TX, City Authority (Hoechst Celanese Corp.), 6.5%, 2026		660,000		659,960
			$	1,735,528
Industrial Revenue - Environmental Services – 1.1%
California Pollution Control Financing Authority, Solid Waste Disposal Rev. (Republic Services, Inc.), “B”, 5.25%, 2023 (b)	$	135,000	$	135,826
California Pollution Control Financing Authority, Solid Waste Disposal Rev. (Waste Management, Inc.), “C”, 5.125%, 2023		655,000		657,338
Carbon County, UT, Solid Waste Disposal Rev. (Laidlaw Environmental), “A”, 7.45%, 2017		500,000		500,390
			$	1,293,554
Industrial Revenue - Metals – 0.3%
State of Indiana Finance Authority, Environmental Rev. (U.S. Steel Corp.), 6%, 2026	$	390,000	$	381,420
Industrial Revenue - Other – 3.1%
Annawan, IL, Tax Increment Rev. (Patriot Renewable Fuels LLC), 5.625%, 2018	$	315,000	$	259,721
California Statewide Communities, Development Authority Facilities (Microgy Holdings Project), 9%, 2038 (d)		53,546		3,079
Gulf Coast, TX, Industrial Development Authority Rev. (CITGO Petroleum Corp.), 8%, 2028		375,000		364,121
Houston, TX, Industrial Development Corp. (United Parcel Service, Inc.), 6%, 2023		435,000		406,094
Indianapolis, IN, Airport Authority Rev., Special Facilities (FedEx Corp.), 5.1%, 2017		500,000		529,020
New Jersey Economic Development Authority Rev. (GMT Realty LLC), “B”, 6.875%, 2037		1,000,000		844,550
Virgin Islands Government Refinery Facilities Rev. (Hovensa Coker Project), 6.5%, 2021		250,000		243,568
Virgin Islands Public Finance Authority, Refinery Facilities Rev. (Hovensa Coker Project), 5.875%, 2022		400,000		365,156
Will-Kankakee, IL, Regional Development Authority Rev. (Flanders Corp.), 6.5%, 2017		500,000		481,920
			$	3,497,229
Industrial Revenue - Paper – 3.7%
Beauregard Parish, LA (Boise Cascade Corp.), 6.8%, 2027	$	1,000,000	$	963,300
Bedford County, VA, Industrial Development Authority Rev. (Nekooska Packaging Corp.), 5.6%, 2025		400,000		370,784
Brunswick & Glynn County, GA, Development Authority Rev. (Georgia-Pacific LLC), 5.55%, 2026		465,000		426,414
Courtland, AL, Industrial Development Board Solid Waste Disposal Rev. (Champion International Corp.), 6%, 2029		1,000,000		959,110
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 5%, 2026		980,000		861,626
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 4.75%, 2030		290,000		246,573
Phenix City, AL, Industrial Development Board Environmental Improvement Rev., “A” (Mead Westvaco Coated Board Project), 6.35%, 2035		400,000		382,836
			$	4,210,643
Miscellaneous Revenue - Entertainment & Tourism – 1.7%
Agua Caliente Band of Cahuilla Indians, CA, Rev., 5.6%, 2013 (n)	$	495,000	$	505,885
Brooklyn, NY, Arena Local Development Corp. (Barclays Center Project), 6%, 2030		135,000		131,228
Brooklyn, NY, Arena Local Development Corp. (Barclays Center Project), 6.25%, 2040		85,000		82,983

7

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Miscellaneous Revenue - Entertainment & Tourism – continued
Brooklyn, NY, Arena Local Development Corp. (Barclays Center Project), 6.375%, 2043	$	65,000	$	64,074
Cow Creek Band of Umpqua Tribe of Indians, OR, “C”, 5.625%, 2026 (n)		650,000		502,782
Mashantucket Western Pequot Tribe, CT, “B”, 0%, 2018 (a)(n)		1,100,000		285,197
New York Liberty Development Corp. Rev. (National Sports Museum), “A”, 6.125%, 2019 (d)		351,999		4
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.125%, 2029		30,000		32,343
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.375%, 2039		25,000		26,390
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.5%, 2046		100,000		106,347
Seminole Tribe, FL, Special Obligation Rev., “A”, 5.25%, 2027 (n)		280,000		233,562
			$	1,970,795
Miscellaneous Revenue - Other – 2.8%
Austin, TX, Convention Center (Convention Enterprises, Inc.), “A”, SYNCORA, 5.25%, 2024	$	305,000	$	274,348
Capital Trust Agency, FL (Aero Syracuse LLC), 6.75%, 2032		350,000		316,054
Dallas, TX, Civic Center Convention Complex Rev., ASSD GTY, 5.25%, 2034		845,000		849,555
New York Liberty Development Corp., Liberty Rev. (One Bryant Park LLC), 6.375%, 2049		955,000		950,158
Summit County, OH, Port Authority Building Rev. (Twinsburg Township), “D”, 5.125%, 2025		630,000		519,265
V Lakes Utility District, MS, Water Systems Rev., 7%, 2037		300,000		254,010
			$	3,163,390
Multi-Family Housing Revenue – 5.3%
Broward County, FL, Housing Finance Authority Rev. (Chaves Lakes Apartments Ltd.), “A”, 7.5%, 2040	$	500,000	$	460,380
Capital Trust Agency, FL, Housing Rev. (Atlantic Housing Foundation), “B”, 7%, 2032 (q)		625,000		305,425
Charter Mac Equity Issuer Trust, FHLMC, 6%, 2019 (n)		1,000,000		1,029,790
District of Columbia Housing Finance Agency (Henson Ridge), “E”, FHA, 5.1%, 2037		655,000		615,320
Durham, NC, Durham Housing Authority Rev. (Magnolia Pointe Apartments), 5.65%, 2038 (b)		922,265		681,600
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “C”, 8%, 2032		275,000		256,666
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “D”, 10%, 2032		280,000		263,469
Minneapolis, MN, Student Housing Rev. (Riverton Community Housing Project), “A”, 5.7%, 2040		500,000		366,580
Mississippi Home Corp., Rev. (Kirkwood Apartments), 6.8%, 2037 (q)		605,000		357,077
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049 (z)		1,000,000		650,220
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016 (z)		455,481		431,035
Wilmington, DE, Multi-Family Housing Rev. (Electra Arms Senior Associates), 6.25%, 2028		805,000		659,408
			$	6,076,970
Sales & Excise Tax Revenue – 5.2%
Bolingbrook, IL, Sales Tax Rev., 6.25%, 2024	$	500,000	$	305,280
Massachusetts School Building Authority, Dedicated Sales Tax Rev., AMBAC, 4.75%, 2032		840,000		841,369
Metropolitan Pier & Exposition Authority, State Tax Rev., Capital Appreciation, NATL, 0%, 2015		3,000,000		2,579,160
Metropolitan Pier & Exposition Authority, State Tax Rev., Capital Appreciation, ETM, FGIC, 0%, 2014		1,010,000		958,197

8

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Sales & Excise Tax Revenue – continued
Puerto Rico Sales Tax Financing Corp., Sales Tax Rev., Capital Appreciation, “A”, 0%, 2032	$	460,000	$	371,836
Regional Transportation District, CO, Private Activity Rev. (Denver Transportation Partners), 6%, 2034		630,000		585,642
Regional Transportation District, CO, Private Activity Rev. (Denver Transportation Partners), 6%, 2041		300,000		273,723
			$	5,915,207
Single Family Housing - Local – 1.2%
Minneapolis & St. Paul Housing Authority Rev. (City Living), “A-2”, GNMA, 5%, 2038	$	499,694	$	458,994
Pittsburgh, PA, Urban Redevelopment Authority Rev., “C”, GNMA, 4.8%, 2028		1,000,000		956,140
			$	1,415,134
Single Family Housing - State – 2.4%
California Housing Finance Agency Rev., “G”, 5.5%, 2042	$	370,000	$	369,782
Colorado Housing & Finance Authority, “A”, 5.5%, 2029		1,115,000		1,144,570
Iowa Finance Authority, Single Family Mortgage Rev., “E”, 5.4%, 2032		480,000		490,579
Kentucky Counties Single Family Mortgage Rev., “A”, NATL, 9%, 2016		5,000		4,999
North Dakota Housing Finance Agency Rev., “A”, 4.85%, 2021		215,000		214,123
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		210,000		216,632
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		340,000		352,036
			$	2,792,721
Solid Waste Revenue – 0.1%
Pennsylvania Economic Development Financing Authority, Sewer Sludge Disposal Rev. (Philadelphia Biosolids Facility), 6.25%, 2032	$	75,000	$	76,727
State & Agency - Other – 0.5%
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.25%, 2024	$	100,000	$	95,337
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.5%, 2037		500,000		453,855
			$	549,192
State & Local Agencies – 4.9%
Dorchester County, SC, School District No. 2, Growth Remedy Opportunity Tax Hike, 5.25%, 2029	$	500,000	$	513,100
Guam Government Department of Education (John F. Kennedy High School), “A”, COP, 6.875%, 2040		295,000		282,221
Laurens County, SC, School District No. 55, Installment Purchase Rev., 5.25%, 2030		700,000		680,659
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024 (c)		45,000		46,268
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024		955,000		956,729
New York Metropolitan Transportation Authority, “A”, 5.125%, 2029		800,000		803,152
Newberry, SC, Investing in Children’s Education (Newberry County School District Program), 5%, 2030		400,000		367,268
Philadelphia, PA, Municipal Authority Rev., 6.5%, 2034		135,000		137,449
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026		820,000		995,603
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026 (c)		80,000		96,112
Wisconsin General Fund Annual Appropriation Rev., “A”, 5.75%, 2033		660,000		697,316
			$	5,575,877
Student Loan Revenue – 0.4%
Massachusetts Educational Financing Authority, Education Loan Rev., “H”, ASSD GTY, 6.35%, 2030	$	445,000	$	449,432
Massachusetts Educational Financing Authority, Education Loan Rev., “I-A”, 5.5%, 2022		25,000		26,154
			$	475,586
Tax - Other – 1.2%
Dallas County, TX, Flood Control District, 7.25%, 2032	$	750,000	$	768,593

9

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tax - Other – continued
New York, NY, City Transitional Finance Authority Building Aid Rev., “S-3”, 5.25%, 2039	$	440,000	$	440,251
Virgin Islands Public Finance Authority Rev. (Diageo Project), “A”, 6.75%, 2037		205,000		209,260
			$	1,418,104
Tax Assessment – 9.0%
Anne Arundel County, MD, Special Obligation (National Business Park-North Project), 6.1%, 2040	$	140,000	$	127,435
Atlanta, GA, Tax Allocation (Eastside Project), “B”, 5.4%, 2020		500,000		497,880
Ave Maria Stewardship Community District, FL, “A”, 5.125%, 2038		150,000		101,145
Capital Region Community Development District, FL, Capital Improvement Rev., “A”, 7%, 2039		235,000		214,922
Celebration Community Development District, FL, “A”, 6.4%, 2034		690,000		680,906
Channing Park Community Development District, FL, 5.3%, 2038		340,000		246,704
Chicago, IL, Tax Increment Allocation (Pilsen Redevelopment), “B”, 6.75%, 2022		310,000		306,311
Du Page County, IL, Special Service Area No. 31 Special Tax (Monarch Landing Project), 5.625%, 2036		250,000		194,643
Heritage Harbour North Community Development District, FL, Capital Improvement Rev., 6.375%, 2038		315,000		247,971
Homestead, FL, Community Development District, Special Assessment, “A”, 6%, 2037		365,000		222,416
Homestead, FL, Community Development District, Special Assessment, “B”, 5.9%, 2013		170,000		103,756
Huntington Beach, CA, Community Facilities District, Special Tax (Grand Coast Resort), “2000-1”, 6.45%, 2031		500,000		485,630
Lincolnshire, IL, Special Service Area No. 1 (Sedgebrook Project), 6.25%, 2034		250,000		214,303
Magnolia Park Community Development District, FL, Special Assessment, “A”, 6.15%, 2039		615,000		488,888
Main Street Community Development District, FL, “A”, 6.8%, 2038		285,000		224,264
Main Street Community Development District, FL, “B”, 6.9%, 2017		225,000		206,460
Northwest Metropolitan District No. 3, CO, 6.25%, 2035		500,000		370,650
Oakmont Grove Community Development District, FL, “A”, 5.4%, 2038 (d)		300,000		111,000
Ohio County, WV, Commission Tax Increment Rev. (Fort Henry Centre), “A”, 5.85%, 2034		125,000		112,825
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.8%, 2026		300,000		279,639
Plano, IL, Special Service Area No. 4 (Lakewood Springs Project Unit 5-B), 6%, 2035		1,460,000		1,230,649
San Diego, CA, Redevelopment Agency, Tax Allocation, AGM, 0%, 2018		1,015,000		701,020
Sarasota National Community Development District, FL, Special Assessment Rev., 5.3%, 2039 (d)		800,000		156,000
Sweetwater Creek Community Development District, FL, Capital Improvement Rev., 5.5%, 2038		190,000		81,700
Tolomato Community Development District, FL, Special Assessment, 6.65%, 2040		585,000		404,323
Tuscany Reserve Community Development District, FL, Special Assessment, “B”, 5.25%, 2016		185,000		150,917
Volo Village, IL, Special Service Area No. 3, Special Tax (Symphony Meadows Project), “1”, 6%, 2036		483,000		338,390
West Villages Improvement District, FL, Special Assessment Rev. (Unit of Development No. 3), 5.5%, 2037		480,000		223,181
Westchester, FL, Community Development District No. 1 (Community Infrastructure), 6.125%, 2035		275,000		233,599
Westridge, FL, Community Development District, Capital Improvement Rev., 5.8%, 2037 (d)		960,000		364,800
Wyandotte County-Kansas City, KS, Unified Government Transportation Development District (Legends Village West Project), 4.875%, 2028		580,000		419,572
Yorba Linda, CA, Redevelopment Agency, Tax Allocation Rev., “A”, NATL, 0%, 2024		1,325,000		553,810
			$	10,295,709

10

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tobacco – 8.6%
Buckeye, OH, Tobacco Settlement Financing Authority, “A-2”, 5.125%, 2024	$	3,270,000	$	2,442,592
Buckeye, OH, Tobacco Settlement Financing Authority, “A-2”, 5.875%, 2030		245,000		174,141
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 6.25%, 2013 (c)(f)		1,155,000		1,250,345
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 5.75%, 2047		525,000		351,787
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, “A-1”, 5%, 2033		440,000		283,122
Inland Empire, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, Capital Appreciation, “C-1”, 0%, 2036		1,815,000		120,716
New Jersey Tobacco Settlement Financing Corp., “1-A”, 4.75%, 2034		260,000		158,582
New Jersey Tobacco Settlement Financing Corp., “1-A”, 5%, 2041		2,940,000		1,761,883
Railsplitter Tobacco Settlement Authority, IL, 6%, 2028		1,320,000		1,283,964
Rhode Island Tobacco Settlement Authority, 6%, 2023		1,530,000		1,553,639
Washington Tobacco Settlement Authority Rev., 6.625%, 2032		500,000		488,525
			$	9,869,296
Toll Roads – 4.9%
E-470 Public Highway Authority, CO, Capital Appreciation, “B”, NATL, 0%, 2018	$	1,500,000	$	953,355
North Texas Tollway Authority Rev., 6%, 2038		765,000		770,003
Pennsylvania Turnpike Commission, Capital Appreciation, “C”, AGM, 0% to 2016, 6.25% to 2033		1,440,000		1,107,130
San Joaquin Hills, CA, Transportation Corridor Agency, Toll Road Rev., Capital Appreciation, “A”, NATL, 0%, 2015		3,000,000		2,359,380
Texas Private Activity Bond, Surface Transportation Corp., 7%, 2040		400,000		405,132
			$	5,595,000
Transportation - Special Tax – 0.2%
Mid-Bay Bridge Authority, FL, Springing Lien Rev., “A”, 7.25%, 2040	$	215,000	$	214,981
Universities - Colleges – 9.6%
Brevard County, FL, Industrial Development Rev. (TUFF Florida Tech LLC Project), 6.75%, 2039	$	540,000	$	526,586
California Educational Facilities Authority Rev. (University of Southern California), “A”, 5.25%, 2038		1,270,000		1,281,798
California Municipal Finance Authority Rev. (Biola University), 5.8%, 2028		100,000		99,017
Florida State University Board of Governors, System Improvement Rev., 6.25%, 2030		1,000,000		1,115,350
Grand Valley, MI, State University Rev., 5.5%, 2027		135,000		139,685
Grand Valley, MI, State University Rev., 5.625%, 2029		65,000		66,871
Harris County, TX, Cultural Education Facilities Rev. (Baylor College of Medicine), “D”, 5.625%, 2032		540,000		491,152
Illinois Finance Authority Rev. (Illinois Institute of Technology), “A”, 5%, 2036		110,000		78,921
Illinois Finance Authority Rev. (Roosevelt University Project), 6.25%, 2029		670,000		651,602
Illinois Finance Authority Rev. (Roosevelt University Project), 6.5%, 2039		155,000		150,899
Illinois Finance Authority Student Housing Rev. (Illinois State University), 6.75%, 2031		240,000		239,460
Massachusetts Health & Educational Facilities Authority Rev. (Simmons College), “I”, 8%, 2029		255,000		281,885
Massachusetts Health & Educational Facilities Authority Rev. (Suffolk University), “A”, 6.25%, 2030		725,000		736,194
Massachusetts Health & Educational Facilities Authority Rev. (Suffolk University), “A”, 5.75%, 2039		455,000		436,563
Ohio Higher Education Facilities Rev. (Ashland University Project), 6.25%, 2024		660,000		646,767
Savannah, GA, Economic Development Authority Rev. (AASU Student Union LLC), ASSD GTY, 5.125%, 2039		1,320,000		1,282,472
University of Illinois Rev. (Auxiliary Facilities Systems), “A”, 5.125%, 2029		1,880,000		1,876,616
University of Southern Indiana Rev. (Student Fee), “J”, ASSD GTY, 5.75%, 2028		300,000		319,617

11

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Universities - Colleges – continued
University of Southern Mississippi Educational Building Corp. Rev. (Campus Facilities Project), 5.25%, 2032	$	220,000	$	225,914
University of Southern Mississippi Educational Building Corp. Rev. (Campus Facilities Project), 5.375%, 2036		80,000		81,390
Washington Higher Education Facilities Authority Rev. (Whitworth University), 5.875%, 2034		280,000		267,784
			$	10,996,543
Universities - Dormitories – 0.7%
California Statewide Communities Development Authority Rev. (Lancer Educational Student Housing Project), 5.625%, 2033	$	735,000	$	586,875
Pennsylvania Higher Education Facilities Authority Rev. (Edinboro University Foundation), 5.8%, 2030		80,000		76,677
Pennsylvania Higher Education Facilities Authority Rev. (Edinboro University Foundation), 6%, 2043		110,000		105,164
			$	768,716
Universities - Secondary Schools – 0.8%
Clifton, TX, Higher Education Finance Corp. Rev. (Uplift Education), “A”, 6.125%, 2040	$	215,000	$	188,675
Clifton, TX, Higher Education Finance Corp. Rev. (Uplift Education), “A”, 6.25%, 2045		135,000		119,158
La Vernia, TX, Higher Education Finance Corp. Rev. (KIPP, Inc.), “A”, 6.25%, 2039		195,000		192,186
Lee County, FL, Industrial Development Authority Rev. (Lee Charter Foundation), “A”, 5.375%, 2037		535,000		404,257
Philadelphia, PA, Authority for Industrial Development Rev. (MaST Charter School), 6%, 2035		50,000		47,484
			$	951,760
Utilities - Cogeneration – 0.7%
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Central Facilities (Cogeneration Facilities - AES Puerto Rico Project), 6.625%, 2026	$	320,000	$	320,954
Suffolk County, NY, Industrial Development Agency Rev. (Nissequoque Cogeneration Partners Facilities), 5.5%, 2023		550,000		485,122
			$	806,076
Utilities - Investor Owned – 5.8%
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 5.75%, 2036 (b)	$	150,000	$	139,850
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 6.75%, 2038		555,000		188,750
Bryant, IL, Pollution Control Rev. (Central Illinois Light Co.), 5.9%, 2023		975,000		977,574
Chula Vista, CA, Industrial Development Rev. (San Diego Gas), 5.875%, 2034		245,000		253,462
Farmington, NM, Pollution Control Rev. (Public Service New Mexico), “D”, 5.9%, 2040		500,000		479,805
Maricopa County, AZ, Pollution Control Corp., Pollution Control Rev. (Arizona Public Service Co.), “D”, 6%, 2029 (b)		475,000		511,547
Massachusetts Development Finance Agency, Solid Waste Disposal Rev. (Dominion Energy Brayton), 5.75%, 2042 (b)		85,000		87,956
Matagorda County, TX, Pollution Control Rev. (Central Power & Light Co.), “A”, 6.3%, 2029		275,000		276,837
Mississippi Business Finance Corp., Pollution Control Rev. (Systems Energy Resources Project), 5.875%, 2022		1,500,000		1,463,610
New Hampshire Business Finance Authority, Pollution Control Rev. (Public Service of New Hampshire), “B”, NATL, 4.75%, 2021		250,000		245,638
Owen County, KY, Waterworks System Rev. (American Water Co. Project), “A”, 6.25%, 2039		205,000		207,210
Pennsylvania Economic Development Financing Authority (Allegheny Energy Supply Co. LLC), 7%, 2039		600,000		630,108
Pima County, AZ, Industrial Development Authority Rev. (Tucson Electric Power Co.), 5.75%, 2029		1,015,000		1,005,875

12

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Utilities - Investor Owned – continued
Sabine River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), 5.75%, 2030 (b)	$	155,000	$	146,449
			$	6,614,671
Utilities - Municipal Owned – 0.1%
Harris County, TX, Cultural Education Facilities Financial Corp., Thermal Utilities Rev. (Teco Project), “A”, 5.25%, 2035	$	140,000	$	140,473
Utilities - Other – 3.8%
California M-S-R Energy Authority Gas Rev., “A”, 7%, 2034	$	155,000	$	170,266
California M-S-R Energy Authority Gas Rev., “A”, 6.5%, 2039		335,000		346,068
Georgia Main Street Natural Gas, Inc., Gas Project Rev., “A”, 5.5%, 2028		335,000		310,686
Georgia Main Street Natural Gas, Inc., Gas Project Rev., “B”, 5%, 2019		325,000		321,399
Indiana Bond Bank Special Program, Gas Rev., “A”, 5.25%, 2018		230,000		242,829
Public Authority for Colorado Energy Natural Gas Purchase Rev., 6.5%, 2038		25,000		25,883
Salt Verde Financial Corp., AZ, Senior Gas Rev., 5%, 2037		705,000		591,389
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2021		1,710,000		1,674,911
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2022		270,000		263,855
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2026		165,000		156,397
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2025		240,000		227,340
			$	4,331,023
Water & Sewer Utility Revenue – 3.1%
Atlanta, GA, Water & Wastewater Rev., “A”, 6%, 2022	$	370,000	$	414,774
Birmingham, AL, Waterworks Board Water Rev., “A”, ASSD GTY, 5.125%, 2034		595,000		593,762
Commonwealth of Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2038		655,000		614,108
Commonwealth of Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2044		135,000		125,315
Detroit, MI, Sewer Disposal System Rev., “B”, AGM, 7.5%, 2033		515,000		603,307
New York, NY, Municipal Water Finance Authority, Water & Sewer Systems Rev. “DD”, 4.75%, 2035		790,000		754,861
Surprise, AZ, Municipal Property Corp., 4.9%, 2032		700,000		595,833
			$	3,701,960
Total Municipal Bonds			$	180,481,756
Money Market Funds (v) – 5.2%
MFS Institutional Money Market Portfolio, 0.2%, at Net Asset Value		5,992,304	$	5,992,304
Total Investments			$	186,474,060
Other Assets, Less Liabilities – 2.8%				3,155,816
Preferred Shares (Issued by the Fund) – (65.4)%				(75,000,000	)
Net assets applicable to common shares – 100.0%			$	114,629,876

(a) Non-income producing security.

(b) Mandatory tender date is earlier than stated maturity date.

(c) Refunded bond.

(d) Non-income producing security - in default.

(f) All or a portion of the security has been segregated as collateral for open futures contracts.

(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers. At period end, the aggregate value of these securities was $2,557,216, representing 2.2% of net assets applicable to common shares.

(q) Interest received was less than stated coupon rate.

(v) Underlying affiliated fund that is available only to investment companies managed by MFS. The rate quoted is the annualized seven-day yield of the fund at period end.

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MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 2/28/11 - continued

(z) Restricted securities are not registered under the Securities Act of 1933 and are subject to legal restrictions on resale. These securities generally may be resold in transactions exempt from registration or to the public if the securities are subsequently registered. Disposal of these securities may involve time-consuming negotiations and prompt sale at an acceptable price may be difficult. The fund holds the following restricted securities:

Restricted Securities	Acquisition Date		Cost		Value
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049		10/14/04	$	1,000,000	$	650,220
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016		10/17/01-1/14/02		455,481		431,035
Total Restricted Securities					$	1,081,255
% of Net Assets Applicable to Common Shares						0.9	%

The following abbreviations are used in this report and are defined:

COP	Certificate of Participation
ETM	Escrowed to Maturity
LOC	Letter of Credit

Insurers
AGM	Assured Guaranty Municipal
AMBAC	AMBAC Indemnity Corp.
ASSD GTY	Assured Guaranty Insurance Co.
CHCLI	California Health Construction Loan Insurance
FGIC	Financial Guaranty Insurance Co.
FHA	Federal Housing Administration
FHLMC	Federal Home Loan Mortgage Corp.
GNMA	Government National Mortgage Assn.
NATL	National Public Finance Guarantee Corp.
PSF	Permanent School Fund
SYNCORA	Syncora Guarantee Inc.

See attached supplemental information. For more information see notes to financial statements as disclosed in the most recent semiannual or annual report.

14

MFS High Yield Municipal Trust

Supplemental Information (Unaudited) 2/28/11

(1) Investment Valuations

Debt instruments and floating rate loans (other than short-term instruments), including restricted debt instruments, are generally valued at an evaluated or composite bid as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less generally are valued at amortized cost, which approximates market value. Futures contracts are generally valued at last posted settlement price as provided by a third-party pricing service on the market on which they are primarily traded. Futures contracts for which there were no trades that day for a particular position are generally valued at the closing bid quotation as provided by a third-party pricing service on the market on which such futures contracts are primarily traded. Open-end investment companies are generally valued at net asset value per share. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. Values obtained from third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, and other market data.

The Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund’s investments (including any fair valuation) to the adviser pursuant to valuation policies and procedures approved by the Board. If the adviser determines that reliable market quotations are not readily available, investments are valued at fair value as determined in good faith by the adviser in accordance with such procedures under the oversight of the Board of Trustees. Under the fund’s valuation policies and procedures, market quotations are not considered to be readily available for most types of debt instruments and floating rate loans and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services. In addition, investments may be valued at fair value if the adviser determines that an investment’s value has been materially effected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund’s net asset value, or after the halting of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund’s net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund’s net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

Various inputs are used in determining the value of the fund’s assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes unobservable inputs, which may include the adviser’s own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments not reflected in total investments, such as futures. The following is a summary of the levels used as of February 28, 2011 in valuing the fund’s assets or liabilities:

Investments at Value	Level 1			Level 2		Level 3		Total
Municipal Bonds	$	—		$	180,481,756	$	—	$	180,481,756
Mutual Funds		5,992,304			—		—		5,992,304
Total Investments	$	5,992,304		$	180,481,756	$	—	$	186,474,060
Other Financial Instruments
Futures	$	(61,489	)	$	—	$	—	$	(61,489	)

For further information regarding security characteristics, see the Portfolio of Investments.

(2) Portfolio Securities

The cost and unrealized appreciation and depreciation in the value of the investments owned by the fund, as computed on a federal income tax basis, are as follows:

Aggregate cost	$	195,978,308
Gross unrealized appreciation	$	6,106,712
Gross unrealized depreciation		(15,610,960	)
Net unrealized appreciation (depreciation)	$	(9,504,248	)

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

15

MFS High Yield Municipal Trust

Supplemental Information (Unaudited) 2/28/11 - continued

(3) Derivative Contracts at 2/28/11

Futures Contracts Outstanding at 2/28/11

Description	Currency		Contracts		Value		Expiration Date		Unrealized Appreciation (Depreciation)
Liability Derivatives
Interest Rate Futures
U.S. Treasury Note 10 yr (Short)		USD		188	$	22,380,813		June-2011	$	(49,127	)
U.S. Treasury Bond 30 yr (Short)		USD		32		3,851,000		June-2011		(12,362	)
									$	(61,489	)

At February 28, 2011, the fund had sufficient cash and/or other liquid securities to cover any commitments under these derivative contracts.

(4) Transactions in Underlying Affiliated Funds-Affiliated Issuers

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the fund assumes the following to be affiliated issuers:

Underlying Affiliated Funds	Beginning Shares/Par Amount		Acquisitions Shares/Par Amount		Dispositions Shares/Par Amount			Ending Shares/Par Amount
MFS Institutional Money Market Portfolio		—		10,283,023		(4,290,719	)		5,992,304
Underlying Affiliated Funds	Realized Gain (Loss)		Capital Gain Distributions		Dividend Income			Ending Value
MFS Institutional Money Market Portfolio	$	—	$	—	$	2,110		$	5,992,304

16

ITEM 2. CONTROLS AND PROCEDURES.

(a) Based upon their evaluation of the effectiveness of the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940 (the “Act”)) as conducted within 90 days of the filing date of this Form N-Q, the registrant’s principal financial officer and principal executive officer have concluded that those disclosure controls and procedures provide reasonable assurance that the material information required to be disclosed by the registrant on this report is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms.

(b) There were no changes in the registrant’s internal controls over financial reporting (as defined in Rule 30a-3(d) under the Act) that occurred during the registrant’s last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

ITEM 3. EXHIBITS.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2): Attached hereto.

Notice

A copy of the Agreement and Declaration of Trust, as amended, of the Registrant is on file with the Secretary of State of The Commonwealth of Massachusetts and notice is hereby given that this instrument is executed on behalf of the Registrant by an officer of the Registrant as an officer and not individually and the obligations of or arising out of this instrument are not binding upon any of the Trustees or shareholders individually, but are binding only upon the assets and property of the respective constituent series of the Registrant.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Registrant: MFS HIGH YIELD MUNICIPAL TRUST

By (Signature and Title)*	MARIA F. DIORIODWYER
	Maria F. DiOrioDwyer, President

Date: April 15, 2011

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)*	MARIA F. DIORIODWYER
	Maria F. DiOrioDwyer, President (Principal Executive Officer)

Date: April 15, 2011

By (Signature and Title)*	JOHN M. CORCORAN
	John M. Corcoran, Treasurer (Principal Financial Officer and Accounting Officer)

Date: April 15, 2011

* Print name and title of each signing officer under his or her signature.