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 811-4992

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, 2009

ITEM 1. SCHEDULE OF INVESTMENTS.

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09

Issuer	Shares/Par		Value ($)
Municipal Bonds – 164.0%
Airport & Port Revenue – 5.0%
Branson, MO, Regional Airport Transportation Development District Airport Rev., “B”, 6%, 2037	$	460,000	$	283,797
Dallas Fort Worth, TX, International Airport Rev. Improvement, “B”, FSA, 5%, 2025		3,000,000		2,740,740
New York, NY, City Industrial Development Authority Rev. (Terminal One Group Assn.), 5.5%, 2021		500,000		447,580
Port Authority NY & NJ, Cons Thirty Seventh, FSA, 5.125%, 2030		1,450,000		1,325,329
			$	4,797,446
General Obligations - General Purpose – 0.4%
Puerto Rico Government Development Bank, “B”, 5%, 2015	$	400,000	$	373,828
General Obligations - Schools – 2.4%
Beverly Hills, CA, Unified School District (Election of 2008), 0%, 2029	$	2,195,000	$	679,353
Beverly Hills, CA, Unified School District (Election of 2008), 0%, 2031		275,000		73,596
Beverly Hills, CA, Unified School District (Election of 2008), 0%, 2032		280,000		69,695
Beverly Hills, CA, Unified School District (Election of 2008), 0%, 2033		560,000		130,726
Irving, TX, Independent School District, “A”, 0%, 2016		1,000,000		792,810
Los Angeles, CA, Unified School District, “D”, 5%, 2034		165,000		157,103
San Jacinto, TX, Community College District, 5.125%, 2038		430,000		421,404
			$	2,324,687
Healthcare Revenue - Hospitals – 39.4%
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5%, 2028	$	435,000	$	251,978
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5.375%, 2040		625,000		345,031
Atchison, KS, Hospital Rev. (Atchison Hospital Assn.), “A”, 6.75%, 2030		320,000		260,566
Brunswick, GA, Hospital Authority Rev. (Glynn-Brunswick Memorial Hospital), 5.625%, 2034		170,000		148,811
California Health Facilities Financing Authority Rev. (Sutter Health), “A”, 5%, 2042		500,000		414,920
California Statewide Communities Development Authority Rev. (Catholic Healthcare West) “K”, ASSD GTY, 5.5%, 2041		625,000		549,669
California Statewide Communities Development Authority Rev. (Catholic Healthcare West) “L”, ASSD GTY, 5.25%, 2041		870,000		733,932
California Statewide Communities Development Authority Rev. (Children’s Hospital), 5%, 2047		290,000		174,392
California Statewide Communities Development Authority Rev. (St. Joseph Health System), FGIC, 5.75%, 2047		635,000		609,949
California Statewide Communities Development Authority Rev. (Sutter Health), “B”, 5.25%, 2048		1,200,000		1,012,620
Colorado Health Facilities Authority Rev. (Poudre Valley Health Care, Inc.), “C”, FSA, 5.25%, 2040		520,000		454,901
Conway, AR, Hospital Rev. (Conway Regional Medical Center), “A”, 6.4%, 2029		350,000		301,599
Conway, AR, Hospital Rev. (Conway Regional Medical Center), “B”, 6.4%, 2029		850,000		732,454
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2016 (c)		965,000		1,022,176
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2026 (c)		500,000		545,230
Dickinson County, MI, Healthcare System Hospital Rev., 5.7%, 2018		770,000		671,548
Garden City, MI, Hospital Finance Authority Rev. (Garden City Hospital), 5%, 2038		500,000		286,905
Genesee County, NY, Industrial Development Agency Civic Facility Rev. (United Memorial Medical Center), 5%, 2027		90,000		62,326
Harris County, TX, Health Facilities Development Corp., Hospital Rev. (Memorial Hermann Healthcare Systems), “B”, 7.25%, 2035		205,000		216,546
Idaho Health Facilities Authority Rev. (IHC Hospitals, Inc.), ETM, 6.65%, 2021 (c)(f)		2,750,000		3,409,560
Illinois Finance Authority Rev. (Children’s Memorial Hospital), “A”, ASSD GTY, 5.25%, 2047		870,000		727,920
Illinois Finance Authority Rev. (Edward Hospital), “A”, AMBAC, 5.5%, 2040		1,090,000		838,014
Illinois Finance Authority Rev. (Kewanee Hospital), 5.1%, 2031		425,000		275,719
Illinois Health Facilities Authority Rev. (Swedish American Hospital), 6.875%, 2010 (c)		500,000		531,115

1

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Indiana Health & Educational Facilities Authority, Hospital Rev. (Community Foundation of Northwest Indiana), 5.5%, 2037	$	1,125,000	$	861,064
Indiana Health & Educational Facilities Finance Authority, Hospital Rev. (Clarian Health), “A”, 5%, 2039		1,745,000		1,257,569
Indiana Health & Educational Facilities Financing Authority Rev. (Sisters of St. Francis Health Services, Inc.), “E”, FSA, 5.25%, 2041		660,000		599,564
Indiana Health Facilities Financing Authority Rev. (Community Foundation of Northwest Indiana ), “A”, 6%, 2034		425,000		351,845
Johnson City, TN, Health & Educational Facilities Board Hospital Rev., 5.5%, 2031		1,120,000		825,082
Johnson City, TN, Health & Educational Facilities Board Hospital Rev. (Mountain States Health), “A”, 5.5%, 2036		410,000		294,757
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.375%, 2024		300,000		298,278
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.625%, 2027		100,000		100,349
Knox County, TN, Health Educational & Housing Facilities, Board Rev. (University Health Systems, Inc.), 5.25%, 2036		415,000		307,432
Lake County, OH, Hospital Facilities Rev. (Lake Hospital Systems, Inc.), 5.625%, 2029		435,000		361,820
Louisiana Public Facilities Authority Hospital Rev. (Lake Charles Memorial Hospital), 6.375%, 2034		830,000		620,732
Louisville & Jefferson County, KY, Metro Government Health Facilities Rev. (Jewish Hospital & St. Mary’s Healthcare), 6.125%, 2037		1,315,000		1,281,915
Louisville & Jefferson County, KY, Metropolitan Government Healthcare Systems Rev. (Norton Healthcare, Inc.), 5.25%, 2036		1,265,000		945,777
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2032		60,000		42,093
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2037		60,000		40,795
Maryland Health & Higher Educational Facilities Authority Rev. (Anne Arundel Health System), “A”, 6.75%, 2039		735,000		746,363
Maryland Health & Higher Educational Facilities Authority Rev. (Medstar Health), BHAC, 5.25%, 2046		440,000		425,322
Maryland Health & Higher Educational Facilities Authority Rev. (Washington County Hospital), 6%, 2043		120,000		91,322
Massachusetts Health & Educational Facilities Authority Rev. (Boston Medical Center), 5.25%, 2038		1,000,000		745,870
Massachusetts Health & Educational Facilities Authority Rev. (Jordan Hospital), “E”, 6.75%, 2033		250,000		194,660
Massachusetts Health & Educational Facilities Authority Rev. (Milford-Whitinsville Hospital), “C”, 5.25%, 2018		500,000		409,095
Massachusetts Health & Educational Facilities Authority Rev. (Quincy Medical Center), “A”, 6.5%, 2038		340,000		230,357
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2031		125,000		90,495
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2036		620,000		434,068
New Hampshire Health & Educational Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2012 (c)		175,000		201,950
New Hampshire Health & Educational Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2032		25,000		19,075
New Hampshire Health & Educational Facilities Authority Rev. (Memorial Hospital at Conway), 5.25%, 2021		530,000		427,450
New Jersey Health Care Facilities, Financing Authority Rev. (St. Peter’s University Hospital), 5.75%, 2037		545,000		411,660
New Mexico State Hospital Equipment Loan Council, Hospital Rev. (Rehoboth McKinley Christian Hospital), “A”, 5%, 2017		285,000		223,104
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.5%, 2030		190,000		192,069

2

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.25%, 2035	$	115,000	$	110,164
Norman, OK, Regional Hospital Authority Rev., 5.375%, 2036		235,000		157,544
Olympia, WA, Healthcare Facilities Authority Rev. (Catholic Health Initiatives), “D”, 6.375%, 2036		1,095,000		1,135,778
Orange County, FL, Health Facilities Authority Hospital Rev. (Orlando Regional Healthcare), 5.75%, 2012 (c)		150,000		171,401
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Hospital), “A”, 5.5%, 2030		480,000		345,850
Philadelphia, PA, Hospitals & Higher Educational Facilities Rev. (Temple University), “A”, 6.625%, 2023		375,000		331,725
Ross County, OH, Hospital Rev. (Adena Health System), 5.75%, 2035		405,000		363,240
Royal Oak, MI, Hospital Finance Authority Rev. (William Beaumont Hospital), 8.25%, 2039		485,000		515,128
Salida, CO, Hospital District Rev., 5.25%, 2036		735,000		428,806
Saline County, MO, Industrial Development Authority Rev. (John Fitzgibbon Memorial Hospital, Inc.), 5.625%, 2035		985,000		673,159
Skagit County, WA, Public Hospital District No. 001 Rev. (Skagit Valley Hospital), 5.75%, 2032		90,000		63,509
South Lake County, FL, Hospital District Rev. (South Lake Hospital, Inc.), 6.375%, 2034		250,000		207,665
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.375%, 2015		500,000		459,125
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.5%, 2020		550,000		467,577
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.125%, 2026		500,000		379,480
Sullivan County, TN, Health, Educational & Housing Facilities Board Hospital Rev. (Wellmont Health Systems Project), “C”, 5.25%, 2036		1,085,000		667,394
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.25%, 2032		230,000		159,408
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.375%, 2037		190,000		130,141
Virginia Small Business Financing Authority Hospital Rev., (Wellmont Health Project), “A”, 5.25%, 2037		470,000		287,222
Washington Health Care Facilities Authority Rev. (Multicare Health Systems), “B”, ASSD GTY, 6%, 2039		440,000		437,545
West Contra Costa, CA, Healthcare District, AMBAC, 5.5%, 2029		105,000		96,249
West Virginia Hospital Finance Authority Rev. (Charleston Medical Center), 6.75%, 2010 (c)		605,000		657,877
Wisconsin Health & Educational Facilities Authority Rev. (Aurora Health Care, Inc.), 6.4%, 2033		350,000		305,928
Wisconsin Health & Educational Facilities Authority Rev. (Fort Healthcare, Inc.), 6.1%, 2034		750,000		642,353
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Healthcare), 5.75%, 2012 (c)		450,000		509,378
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Healthcare), 5.25%, 2034		935,000		575,446
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), “A”, 5.25%, 2025		390,000		271,077
			$	38,159,982
Healthcare Revenue - Long Term Care – 27.7%
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement), “A”, 5.9%, 2025	$	750,000	$	521,693
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement), “A”, 7%, 2033		200,000		148,632
Boston, MA, Industrial Development Financing Authority Rev. (Springhouse, Inc.), 5.875%, 2020		235,000		181,805
Bucks County, PA, Industrial Development Authority Retirement Community Rev. (Ann’s Choice, Inc.), “A”, 6.125%, 2025		500,000		364,150

3

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Bucks County, PA, Industrial Development Authority Retirement Community Rev. (Ann’s Choice, Inc.), “A”, 6.25%, 2035	$	250,000	$	169,445
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2027		90,000		62,250
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2037		120,000		76,274
California Statewide Communities Development Authority Rev. (Eskaton Properties, Inc.), 8.25%, 2010 (c)		695,000		778,588
Capital Projects Finance Authority, FL (Glenridge on Palmer Ranch), “A”, 8%, 2012 (c)		500,000		606,960
Chartiers Valley, PA, Industrial & Commercial Development Authority (Friendship Village), “A”, 5.75%, 2020		1,000,000		803,050
Chartiers Valley, PA, Industrial & Commercial Development Authority Rev. (Asbury Health Center), 6.375%, 2024		1,000,000		837,770
Colorado Health Facilities Authority Rev. (American Housing Foundation, Inc.), 8.5%, 2011 (c)		530,000		620,657
Colorado Health Facilities Authority Rev. (Christian Living Communities Project), “A”, 5.75%, 2037		500,000		316,475
Colorado Health Facilities Authority Rev. (Covenant Retirement Communities, Inc.), 5%, 2035		1,100,000		723,206
Columbus, GA, Housing Authority Rev. (Calvary Community, Inc.), 7%, 2019		425,000		338,517
Fulton County, GA, Residential Care Facilities (Canterbury Court), “A”, 6.125%, 2026		500,000		371,645
Fulton County, GA, Residential Care Facilities, First Mortgage (Lenbrook Square Foundation, Inc.), “A”, 5%, 2029		1,500,000		897,915
HFDC of Central Texas, Inc., Retirement Facilities Rev. (Legacy at Willow Bend), “A”, 5.75%, 2036		600,000		360,600
Houston, TX, Health Facilities Development Corp., (Buckingham Senior Living Community), “A”, 7%, 2014 (c)		500,000		600,480
Howard County, MD, Retirement Facilities Rev. (Vantage House Corp.), “A”, 5.25%, 2033		200,000		120,088
Huntington, NY, Housing Authority Rev. (Gurwin Senior Jewish Residences), “A”, 5.875%, 2019		420,000		327,159
Huntington, NY, Housing Authority Rev. (Gurwin Senior Jewish Residences), “A”, 6%, 2029		650,000		441,253
Illinois Finance Authority Rev. (Smith Village), “A”, 6.25%, 2035		1,000,000		718,040
Illinois Health Facilities Authority Rev. (Smith Crossing), “A”, 7%, 2032		525,000		419,302
Indiana Health Facilities Financing Authority Rev. (Hoosier Care, Inc.), 7.125%, 2034		1,010,000		734,199
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), 9.25%, 2011(c)		915,000		1,090,854
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2018		550,000		453,860
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2028		1,475,000		1,012,912
James City County, VA, Economic Development (WindsorMeade Project), “A”, 5.5%, 2037		520,000		288,210
Johnson City, TN, Health & Educational Facilities Board (Appalachian Christian Village), “A”, 6.25%, 2032		250,000		175,678
Juneau, AK, City & Borough Non-Recourse Rev. (St. Ann’s Care Project), 6.875%, 2025		900,000		704,340
Kent County, DE, Assisted Living (Heritage at Dover LLC), 7.625%, 2030		1,120,000		781,738
Kentucky Economic Development Finance Authority Health Facilities Rev. (AHF/Kentucky-IOWA, Inc.), 8%, 2029		395,000		304,371
La Verne, CA, COP (Brethren Hillcrest Homes), “B”, 6.625%, 2025		525,000		418,955
Lancaster, PA, Industrial Development Authority Rev. (Garden Spot Village), “A”, 7.625%, 2010 (c)		325,000		354,260
Massachusetts Development Finance Agency Rev. (Adventcare), “A”, 6.75%, 2037		695,000		486,722
Massachusetts Development Finance Agency Rev. (Alliance Health of Brockton, Inc.), “A”, 7.1%, 2032		1,080,000		804,092
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.5%, 2027		185,000		110,591

4

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PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.75%, 2035	$	45,000	$	25,487
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 5.625%, 2015		250,000		222,993
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 6.9%, 2032		125,000		103,319
Massachusetts Industrial Finance Agency Rev. (GF/Massachusetts, Inc.), 8.3%, 2023		780,000		438,110
Metropolitan Government of Nashville & Davidson County, TN, Health & Educational Facilities Board Rev. (Blakeford at Green Hills), 5.65%, 2024		575,000		414,914
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.125%, 2028		150,000		93,519
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.25%, 2035		600,000		355,680
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.75%, 2025		400,000		286,336
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.875%, 2037		300,000		195,978
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2026		500,000		360,865
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2036		500,000		323,705
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), “A”, 8.25%, 2010 (c)		700,000		783,538
Roseville, MN, Elder Care Facilities (Care Institute, Inc.), 7.75%, 2023		1,630,000		1,178,783
Sartell, MN, Health Care & Housing Authority Rev. (The Foundation for Health Care), “A”, 6.625%, 2029		1,025,000		818,288
Savannah, GA, Economic Development Authority, First Mortgage (Marshes of Skidway), “A”, 7.4%, 2034		350,000		280,844
Shelby County, TN, Health, Educational & Housing Facilities Board Rev. (Germantown Village), “A”, 7.25%, 2034		300,000		226,086
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2027		280,000		183,616
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2042		260,000		152,513
South Carolina Jobs & Economic Development Authority, Health Facilities Rev. (Wesley Commons), 5.3%, 2036		200,000		118,150
St. Johns County, FL, Industrial Development Authority (Glenmoor Project), “A”, 5.25%, 2026		500,000		304,455
Westmoreland County, PA, Industrial Development Authority Rev. (Redstone Retirement Community), “A”, 5.875%, 2032		600,000		400,104
Westmoreland County, PA, Industrial Development Retirement Authority Rev. (Redstone Retirement Community), “A”, 5.75%, 2026		1,250,000		874,738
Wisconsin Health & Educational Facilities Board Rev. (All Saints Assisted Living Project), 6%, 2037		180,000		113,672
			$	26,782,429
Healthcare Revenue - Other – 0.8%
Massachusetts Health & Educational Facilities Authority Rev. (Civic Investments, Inc.), “A”, 9%, 2012 (c)	$	650,000	$	779,721
Industrial Revenue - Airlines – 4.1%
Alliance Airport Authority, TX (American Airlines, Inc.), 5.25%, 2029	$	1,560,000	$	621,894
Chicago, IL, O’Hare International Airport Special Facilities Rev. (American Airlines, Inc.), 5.5%, 2030		1,745,000		745,900
Cleveland, OH, Airport Special Rev. (Continental Airlines, Inc.), 5.7%, 2019		875,000		524,099
Dallas Fort Worth, TX, International Airport Facility Improvement Corp. (American Airlines, Inc.), 5.5%, 2030		750,000		325,185
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 9%, 2033 (a)		1,250,000		1,062,213
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.625%, 2025		40,000		29,791

5

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PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue - Airlines – continued
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.75%, 2031	$	385,000	$	288,038
New York, NY, City Industrial Development Agency Special Facility Rev. (American Airlines, Inc.), “B”, 8.5%, 2028		500,000		399,835
			$	3,996,955
Industrial Revenue - Chemicals – 0.3%
Brazos River, TX, Harbor Navigation District (Dow Chemical Co.), “B-2”, 4.95%, 2033	$	400,000	$	251,744
Industrial Revenue - Environmental Services – 2.1%
California Pollution Control Financing Authority, Solid Waste Disposal Rev. (Waste Management, Inc.), “C”, 5.125%, 2023	$	655,000	$	540,866
Carbon County, UT, Solid Waste Disposal Rev. (Allied Waste Industries), “A”, 7.5%, 2010		250,000		251,433
Carbon County, UT, Solid Waste Disposal Rev. (Laidlaw Environmental), “A”, 7.45%, 2017		500,000		491,920
Gulf Coast Waste Disposal Authority, TX (Waste Management of Texas), “A”, 5.2%, 2028		360,000		269,107
New Hampshire Business Finance Authority, Solid Waste Disposal Rev. (Waste Management, Inc.), 5.2%, 2027		660,000		483,008
			$	2,036,334
Industrial Revenue - Metals – 0.6%
Director of Nevada Department of Business & Industry (Wheeling/Pittsburgh Steel), “A”, 8%, 2014	$	150,000	$	141,269
Greensville County, VA, Industrial Development Authority Rev. (Wheeling/Pittsburgh Steel), “A”, 7%, 2014		435,000		398,804
			$	540,073
Industrial Revenue - Other – 4.5%
Annawan, IL, Tax Increment Rev. (Patriot Renewable Fuels LLC), 5.625%, 2018	$	350,000	$	256,232
California Statewide Communities Development Authority Facilities (Microgy Holdings Project), 9%, 2038		400,000		336,440
Gulf Coast, TX, Industrial Development Authority Rev. (CITGO Petroleum Corp.), 8%, 2028		375,000		328,493
Houston, TX, Industrial Development Corp. (United Parcel Service, Inc.), 6%, 2023		455,000		342,570
Indianapolis, IN, Airport Authority Rev., Special Facilities (FedEx Corp.), 5.1%, 2017		500,000		427,230
Michigan Strategic Fund Rev. (Michigan Sugar Co.), “A”, 6.25%, 2015		1,000,000		911,350
New Jersey Economic Development Authority Rev. (GMT Realty LLC), “B”, 6.875%, 2037		1,000,000		735,360
Virgin Islands Government Refinery Facilities Rev. (Hovensa Coker Project), 6.5%, 2021		250,000		189,755
Virgin Islands Public Finance Authority, Refinery Facilities Rev. (Hovensa Coker Project), 5.875%, 2022		400,000		273,360
Will-Kankakee, IL, Regional Development Authority Rev. (Flanders Corp.), 6.5%, 2017		605,000		513,439
			$	4,314,229
Industrial Revenue - Paper – 2.9%
Beauregard Parish, LA (Boise Cascade Corp.), 6.8%, 2027	$	1,000,000	$	514,680
Bedford County, VA, Industrial Development Authority Rev. (Nekooska Packaging Corp.), 5.6%, 2025		400,000		224,924
Camden, AL, Industrial Development Board Exempt Facilities Rev., “B” (Weyerhaeuser Co.), 6.375%, 2013 (c)		400,000		457,332
Courtland AL, Industrial Development Board Solid Waste Disposal Rev. (Champion International Corp.), 6%, 2029		1,000,000		666,520
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 4.75%, 2030		290,000		150,991
Escambia County, FL, Environmental Improvement Rev. (International Paper Co., Projects), “A”, 5%, 2026		980,000		577,347

6

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue - Paper – continued
Phenix City, AL, Industrial Development Board Environmental Improvement Rev., “A” (MeadWestvaco Coated), 6.35%, 2035	$	400,000	$	248,136
			$	2,839,930
Miscellaneous Revenue - Entertainment & Tourism – 2.8%
Agua Caliente Band of Cahuilla Indians, CA, 5.6%, 2013 (z)	$	775,000	$	723,804
Cabazon Band Mission Indians, CA, 8.375%, 2015 (z)		150,000		138,398
Cabazon Band Mission Indians, CA, 8.75%, 2019 (z)		720,000		653,249
Cow Creek Band of Umpqua Tribe of Indians, OR, “C”, 5.625%, 2026 (n)		650,000		426,953
Mashantucket Western Pequot Tribe, CT, “B”, 0%, 2018 (n)		1,100,000		422,488
New York Liberty Development Corp. Rev. (National Sports Museum), “A”, 6.125%, 2019 (b)		351,999		352
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.125%, 2029		30,000		31,874
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.375%, 2039		25,000		26,447
New York, NY, City Industrial Development Agency Rev. (Queens Baseball Stadium), ASSD GTY, 6.5%, 2046		100,000		105,945
Seminole Tribe, FL, Special Obligation, “A”, 5.25%, 2027 (n)		280,000		182,918
			$	2,712,428
Miscellaneous Revenue - Other – 2.4%
Austin, TX, Convention Center (Convention Enterprises, Inc.), “A”, XLCA, 5.25%, 2024	$	115,000	$	82,361
Capital Trust Agency, FL (Aero Syracuse LLC), 6.75%, 2032		350,000		255,745
Dallas, TX, Civic Center Convention Complex Rev., ASSD GTY, 5.25%, 2034		845,000		829,841
Massachusetts Development Finance Agency (Boston Biomedical Research), 5.65%, 2019		620,000		514,081
Summit County, OH, Port Authority Building Rev. (Twinsburg Township), “D”, 5.125%, 2025		630,000		440,351
V Lakes Utility District Ranking Water Systems Rev., 7%, 2037		300,000		228,780
			$	2,351,159
Multi-Family Housing Revenue – 9.1%
Broward County, FL, Housing Finance Authority Rev. (Chaves Lakes Apartments Ltd.), “A”, 7.5%, 2040	$	500,000	$	426,410
Capital Trust Agency, FL, Housing Rev. (Atlantic Housing Foundation), “B”, 7%, 2032		645,000		514,252
Charter Mac Equity Issuer Trust, FHLMC, 6%, 2019 (n)		1,000,000		892,610
Charter Mac Equity Issuer Trust, “B”, FHLMC, 7.6%, 2010 (a)(n)		500,000		506,540
Clay County, FL, Housing Finance Authority Rev. (Madison Commons Apartments), “A”, 7.45%, 2040		495,000		405,098
District of Columbia Housing Finance Agency (Henson Ridge), “E”, FHA, 5.1%, 2037		655,000		573,564
Durham, NC, Durham Housing Authority Rev. (Magnolia Pointe Apartments), 5.65%, 2038 (a)		935,657		701,527
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “D”, 10%, 2032		290,000		244,978
El Paso County, TX, Housing Finance Corp. (American Housing Foundation, Inc.), “C”, 8%, 2032		285,000		233,292
Massachusetts Housing Finance Agency Rev., “B”, 5%, 2030		500,000		477,295
Massachusetts Housing Finance Agency Rev., “E”, 5%, 2028		500,000		453,270
Minneapolis, MN, Student Housing Rev. (Riverton Community Housing Project), “A”, 5.7%, 2040		500,000		335,600
Mississippi Home Corp., Rev. (Kirkwood Apartments), 6.8%, 2037		605,000		449,914
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049 (z)		1,000,000		669,020
New Mexico Mortgage Finance Authority, Multi-Family Housing Rev. (Sun Pointe Apartments), “E”, FHA, 4.8%, 2040		500,000		409,005
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016 (z)		455,481		417,631
Seattle, WA, Housing Authority Rev., Capped Fund Program (High Rise Rehab), “I”, FSA, 5%, 2025		500,000		467,715

7

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Multi-Family Housing Revenue – continued
Wilmington, DE, Multi-Family Housing Rev. (Electra Arms Senior Associates), 6.25%, 2028	$	850,000	$	618,970
			$	8,796,691
Sales & Excise Tax Revenue – 4.5%
Bolingbrook, IL, Sales Tax Rev., 6.25%, 2024	$	500,000	$	333,550
Massachusetts School Building Authority, Dedicated Sales Tax Rev., AMBAC, 4.75%, 2032		840,000		795,631
Metropolitan Pier & Exposition Authority, State Tax Rev., MBIA, 0%, 2015		3,000,000		2,375,640
Metropolitan Pier & Exposition Authority, State Tax Rev., ETM, FGIC, 0%, 2014 (c)		1,010,000		871,620
			$	4,376,441
Single Family Housing - Local – 1.6%
Minneapolis & St. Paul Housing Authority Rev. (City Living), “A-2”, GNMA, 5%, 2038	$	711,296	$	590,952
Pittsburgh, PA, Urban Redevelopment Authority Rev., “C”, GNMA, 4.8%, 2028		1,000,000		929,460
			$	1,520,412
Single Family Housing - State – 3.5%
California Housing Finance Agency Rev., “J”, 5.75%, 2047	$	1,500,000	$	1,488,330
Iowa Finance Authority, Single Family Mortgage Rev., “E”, 5.4%, 2032		920,000		906,724
Kentucky Counties Single Family Mortgage Rev., “A”, MBIA, 9%, 2016		5,000		5,001
North Dakota Housing Finance Agency Rev., “A”, 4.85%, 2021		475,000		462,199
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		210,000		207,969
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		340,000		336,467
			$	3,406,690
State & Agency - Other – 0.5%
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.25%, 2024	$	100,000	$	82,937
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.5%, 2037		500,000		387,585
			$	470,522
State & Local Agencies – 4.3%
Dorchester County, SC, School District No. 2, Growth Remedy Opportunity Tax Hike, 5.25%, 2029	$	500,000	$	492,505
Laurens County, SC, School District No. 55, Installment Purchase Rev., 5.25%, 2030		700,000		580,083
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024		1,000,000		941,000
New York Metropolitan Transportation Authority, “A”, 5.125%, 2029		800,000		778,104
Newberry, SC, Investing in Children’s Education (Newberry County School District Program), 5%, 2030		400,000		318,976
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026 (c)		80,000		92,893
Puerto Rico Public Finance Corp., Unrefunded, “E”, ETM, 6%, 2026 (c)		820,000		952,151
			$	4,155,712
Student Loan Revenue – 0.6%
Massachusetts Educational Financing Authority, Education Loan Rev., “H”, , 6.35%, 2030	$	625,000	$	587,550
Tax - Other – 1.4%
Dallas County, TX, Flood Control District, 7.25%, 2032	$	750,000	$	631,433
New Jersey Economic Development Authority Rev. (Cigarette Tax), 5.75%, 2029		385,000		285,951
New York, NY, City Transitional Finance Authority Building Aid Rev., “S-3”, 5.25%, 2039		440,000		423,927
			$	1,341,311
Tax Assessment – 11.0%
Atlanta, GA, Tax Allocation (Eastside Project), “B”, 5.4%, 2020	$	500,000	$	358,045
Ave Maria Stewardship Community District, FL, “A”, 5.125%, 2038		150,000		74,177
Capital Region Community Development District Rev., FL, “A”, 7%, 2039		235,000		165,062
Celebration Community Development District, FL, “A”, 6.4%, 2034		710,000		618,524
Channing Park Community Development District, FL, 5.3%, 2038		400,000		201,412
Chicago, IL, Tax Increment Allocation (Pilsen Redevelopment), “B”, 6.75%, 2022		310,000		256,392

8

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tax Assessment – continued
Du Page County, IL, Special Service Area No. 31 Special Tax (Monarch Landing Project), 5.625%, 2036	$	250,000	$	147,725
Durbin Crossing Community Development District, FL, Special Assessment, “B-1”, 4.875%, 2010		175,000		118,251
Grand Bay at Doral Community Development District, FL, “A”, 6%, 2039		90,000		50,084
Grand Bay at Doral Community Development District, FL, “B”, 6%, 2017		545,000		396,580
Heritage Harbour North Community Development District, FL, Capital Improvement Rev., 6.375%, 2038		325,000		202,163
Homestead 50 Community Development District, FL, “A”, 6%, 2037		375,000		222,581
Homestead 50 Community Development District, FL, “B”, 5.9%, 2013		170,000		143,551
Huntington Beach, CA, Community Facilities District, Special Tax (Grand Coast Resort), “2000-1”, 6.45%, 2031		500,000		406,340
Lincoln, CA, Special Tax (Community Facilities District ), “2003-1”, 5.55%, 2013 (c)		440,000		513,788
Lincolnshire, IL, Special Service Area No. 1 (Sedgebrook Project), 6.25%, 2034		250,000		166,063
Magnolia Park Community Development District, FL, Special Assessment, “A”, 6.15%, 2039		615,000		368,877
Main Street Community Development District, FL, “A”, 6.8%, 2038		295,000		188,307
Main Street Community Development District, FL, “B”, 6.9%, 2017		225,000		169,315
Northwest Metropolitan District No. 3, CO, 6.25%, 2035		500,000		273,450
Oakmont Grove Community Development District, CA, “A”, 5.4%, 2038		300,000		133,476
Ohio County, WV, Commission Tax Increment Rev. (Fort Henry Centre), “A”, 5.85%, 2034		125,000		79,501
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.5%, 2010		45,000		43,995
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.8%, 2026		300,000		245,448
Plano, IL, Special Service Area No. 4 (Lakewood Springs Project Unit 5-B), 6%, 2035		1,490,000		931,846
Portage, IN, Economic Development Rev. (Ameriplex Project), 5%, 2027		260,000		171,530
San Diego, CA, Redevelopment Agency, Tax Allocation, FSA, 0%, 2018		1,015,000		680,304
Sarasota National Community Development District, FL, Special Assessment Rev., 5.3%, 2039		800,000		407,960
Seven Oaks, FL, Community Development District II Special Assessment Rev., “B”, 5%, 2009		575,000		345,633
Sweetwater Creek Community Development District, FL, Capital Improvement Rev., 5.5%, 2038		200,000		94,496
Tolomato Community Development District, FL, Special Assessment, 6.65%, 2040		585,000		358,459
Tuscany Reserve Community Development District, FL, Special Assessment, “B”, 5.25%, 2016		185,000		99,911
Volo Village, IL, Special Service Area No. 3, Special Tax (Symphony Meadows Project), “1”, 6%, 2036		484,000		260,077
West Villages Improvement District, FL, Special Assessment Rev. (Unit of Development No. 3), 5.5%, 2037		495,000		281,259
Westchester, FL, Community Development District No. 1 (Community Infrastructure), 6.125%, 2035		275,000		177,755
Westridge, FL, Community Development District, Capital Improvement Rev., 5.8%, 2037 (b)		980,000		444,499
Wyandotte County-Kansas City, KS, Unified Government Transportation Development District (Legends Village West Project), 4.875%, 2028		580,000		346,997
Yorba Linda, CA, Redevelopment Agency, Tax Allocation Rev., “A”, MBIA, 0%, 2024		1,325,000		551,399
			$	10,695,232
Tobacco – 8.9%
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 5.875%, 2030	$	1,610,000	$	1,016,055
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 5.875%, 2047		2,810,000		1,584,981
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 6.5%, 2047		785,000		488,717
California County, CA, Tobacco Securitization Agency, Tobacco Settlement Rev. (Los Angeles County), 0%, 2046		3,500,000		57,365

9

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tobacco – continued
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 6.25%, 2013 (c)	$	1,495,000	$	1,647,445
Inland Empire, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, “C-1”, 0%, 2036		1,815,000		108,210
Michigan Tobacco Settlement Finance Authority Rev., Asset Backed, “A”, 6%, 2048		1,710,000		1,003,172
Rhode Island Tobacco Settlement Authority, 6%, 2023		2,115,000		1,881,885
Tobacco Settlement Authority of Washington Rev., Asset Backed, 6.625%, 2032		500,000		356,790
Virginia Tobacco Settlement Financing Corp., “B-1”, 5%, 2047		830,000		431,592
			$	8,576,212
Toll Roads – 5.6%
Bay Area Toll Authority, Toll Bridge Rev. (San Francisco Bay Area), “F1”, 5%, 2034	$	1,445,000	$	1,394,887
E-470 Public Highway Authority, CO, “B”, MBIA, 0%, 2018		1,500,000		796,485
E-470 Public Highway Authority, CO, “B”, 0%, 2010 (c)		8,750,000		1,299,113
San Joaquin Hills, CA, Transportation Corridor Agency Toll Road Rev., “A”, MBIA, 0%, 2015		3,000,000		1,983,060
			$	5,473,545
Universities - Colleges – 5.3%
California Educational Facilities Authority Rev. (University of Southern California), “A”, 5.25%, 2038	$	1,270,000	$	1,298,727
California Municipal Finance Authority Rev. (Biola University), 5.8%, 2028		100,000		83,857
Florida State University Board of Governors, System Improvement Rev., 6.25%, 2030		1,000,000		1,061,630
Grand Valley, MI, State University Rev., 5.5%, 2027		135,000		132,971
Grand Valley, MI, State University Rev., 5.625%, 2029		65,000		64,017
Harris County, TX, Cultural Education Facilities Rev. (Baylor College of Medicine), “D”, 5.625%, 2032		280,000		268,834
Massachusetts Health & Educational Facilities Authority Rev. (Simmons College), “I”, 8%, 2029		255,000		262,829
Savannah, GA, Economic Development Authority Rev. (AASU Student Union, LLC), ASSD GTY, 5.125%, 2039		1,320,000		1,285,244
University of Southern Indiana Rev., Student Fee, “J”, ASSD GTY, 5.75%, 2028		300,000		313,776
University of Southern Mississippi Educational Building Corp. (Campus Facilities Project), 5.25%, 2032		265,000		259,742
University of Southern Mississippi Educational Building Corp. (Campus Facilities Project), 5.375%, 2036		80,000		78,814
			$	5,110,441
Universities - Dormitories – 0.4%
California Statewide Communities Development Authority Rev. (Lancer Educational Student Housing Project), 5.625%, 2033	$	735,000	$	442,176
Universities - Secondary Schools – 1.5%
California Statewide Communities Development Authority Rev., COP, (Crossroads Schools for the Arts & Sciences), 6%, 2028	$	1,010,000	$	849,269
Colorado Housing Finance Development Rev. (Evergreen Country Day School), 5.875%, 2037		425,000		294,772
Lee County, FL, Industrial Development Authority Rev. (Lee Charter Foundation), “A”, 5.375%, 2037		535,000		299,750
			$	1,443,791
Utilities - Cogeneration – 0.7%
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Central Facilities (Cogeneration Facilities - AES Puerto Rico Project), 6.625%, 2026	$	320,000	$	286,019
Suffolk County, NY, Industrial Development Agency Rev. (Nissequoque Cogeneration Partners Facilities), 5.5%, 2023		550,000		420,926
			$	706,945
Utilities - Investor Owned – 4.9%
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 5.75%, 2036 (a)	$	220,000	$	150,528

10

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Utilities - Investor Owned – continued
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 6.75%, 2038	$	555,000	$	242,657
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “D”, 5.4%, 2029 (a)		45,000		29,232
Bryant, IL, Pollution Control Rev. (Central Illinois Light Co.), 5.9%, 2023		975,000		974,912
Clark County, NV, Industrial Development Rev. (Nevada Power Co. Project), “A”, 5.9%, 2032		1,500,000		1,049,700
Mississippi Business Finance Corp., Pollution Control Rev. (Systems Energy Resources Project), 5.875%, 2022		1,500,000		1,274,565
New Hampshire Business Finance Authority, Pollution Control Rev. (Public Service of New Hampshire), “B”, MBIA, 4.75%, 2021		250,000		192,420
Red River Authority, TX, Pollution Control Rev. (AEP Texas Central Co.), MBIA, 4.45%, 2020		410,000		341,920
Sabine River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), 5.2%, 2028		185,000		82,640
Sabine River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), 5.75%, 2030 (a)		155,000		106,054
West Feliciana Parish, LA, Pollution Control Rev. (Entergy Gulf States), 6.6%, 2028		270,000		258,603
			$	4,703,231
Utilities - Other – 2.8%
Main Street Natural Gas, Inc., GA, Gas Project Rev., “A”, 5.5%, 2028	$	335,000	$	238,942
Main Street Natural Gas, Inc., GA, Gas Project Rev., “B”, 5%, 2019		325,000		256,867
Salt Verde Financial Corp., AZ, Senior Gas Rev., 5%, 2037		705,000		447,499
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2021		1,710,000		1,264,254
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2022		270,000		196,136
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2026		165,000		112,448
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2025		240,000		161,854
			$	2,678,000
Water & Sewer Utility Revenue – 2.0%
New York, NY, City Municipal Water Finance Authority, Water & Sewer Systems Rev. “DD”, 4.75%, 2035	$	790,000	$	726,263
Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2038		655,000		595,886
Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2044		135,000		120,763
Surprise, AZ, Municipal Property Corp., 4.9%, 2032		700,000		488,138
			$	1,931,050
Total Municipal Bonds			$	158,676,897
Floating Rate Demand Notes – 6.1%
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), 0.3%, due 3/02/09	$	1,500,000	$	1,500,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), “A”, 0.5%, due 3/02/09		1,200,000		1,200,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), “C”, 0.5%, due 3/02/09		3,235,000		3,235,000
Total Floating Rate Demand Notes			$	5,935,000
Total Investments			$	164,611,897
Other Assets, Less Liabilities – 7.4%				7,146,686
Preferred shares (issued by the trust) – (77.5)%				(75,000,000	)
Net assets applicable to common shares – 100.0%			$	96,758,583

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

(b) Non-income producing security.

(c) Refunded bond.

(d) Non-income producing security - in default, or is anticipated to default on next payment. (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 $2,431,509, representing 2.51% of net assets applicable to common shares.

11

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 2/28/09 - 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		Current Market Value
Agua Caliente Band of Cahuilla Indians, CA, 5.6%, 2013	7/22/03	$	775,977	$	723,804
Cabazon Band Mission Indians, CA, 8.375%, 2015	10/04/04		150,000		138,398
Cabazon Band Mission Indians, CA, 8.75%, 2019	10/04/04		720,000		653,249
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049	10/14/04		1,000,000		669,020
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016	10/17/01-1/14/02		455,481		417,631
Total Restricted Securities				$	2,602,102
% of Net Assets Applicable to Common Shares					2.7	%

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

COP	Certificate of Participation
ETM	Escrowed to Maturity
LOC	Letter of Credit
Insurers
AMBAC	AMBAC Indemnity Corp.
ASSD GTY	Assured Guaranty Insurance Co.
BHAC	Berkshire Hathaway Assurance Corp.
FGIC	Financial Guaranty Insurance Co.
FHA	Federal Housing Administration
FHLMC	Federal Home Loan Mortgage Corp.
FSA	Financial Security Assurance Inc.
GNMA	Government National Mortgage Assn.
MBIA	MBIA Insurance Corp.
XLCA	XL Capital Insurance Co.

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

12

MFS High Yield Municipal Trust

Supplemental Information (Unaudited) 2/28/09

(1) Fair Value Disclosure

The fund adopted FASB Statement No. 157, Fair Value Measurements (the “Statement”). This Statement provides a single definition of fair value, a hierarchy for measuring fair value and expanded disclosures about fair value measurements.

Various inputs are used in determining the value of the fund’s assets or liabilities carried at market value. These inputs are categorized into three broad levels. Level 1 includes 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, forwards, swap contracts, and written options. The following is a summary of the levels used as of February 28, 2009 in valuing the fund’s assets or liabilities carried at market value:

	Level 1		Level 2		Level 3		Total
Investments in Securities	$	—	$	164,611,897	$	—	$	164,611,897
Other Financial Instruments	$	502,368	$	—	$	—	$	502,368

(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	$	196,943,612
Gross unrealized appreciation	$	4,184,465
Gross unrealized depreciation		(36,516,180	)
Net unrealized appreciation (depreciation)	$	(32,331,715	)

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

(3) Derivative Contracts at 2/28/09

Futures contracts outstanding at 2/28/09

Description	Contracts	Value	Expiration Date	Unrealized Appreciation (Depreciation)
U.S. Treasury Note 10 yr (Short)	264	31,688,250	Jun-09	$	154,730
U.S. Treasury Note 30 yr (Short)	46	5,673,813	Jun-09		347,638
				$	502,368

At February 28, 2009, the fund had sufficient cash and/or other liquid securities to cover any commitments under these derivative contracts.

13

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. DWYER
	Maria F. Dwyer, President

Date: April 20, 2009

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. DWYER
	Maria F. Dwyer, President (Principal Executive Officer)

Date: April 20, 2009

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

Date: April 20, 2009

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