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: August 31, 2008

ITEM 1. SCHEDULE OF INVESTMENTS.

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08

Issuer	Shares/Par		Value ($)
Municipal Bonds – 159.9%
Airport & Port Revenue – 3.9%
Branson, MO, Regional Airport Transportation Development District Airport Rev., “B”, 6%, 2037	$	460,000	$	377,117
Dallas Fort Worth, TX, International Airport Rev. Improvement, “B”, FSA, 5%, 2025		3,000,000		2,806,080
New York, NY, City Industrial Development Authority Rev. (Terminal One Group Assn.), 5.5%, 2021		500,000		512,060
Port Authority NY & NJ, Cons Thirty Seventh, FSA, 5.125%, 2030 (f)		1,450,000		1,415,447
			$	5,110,704
General Obligations – General Purpose – 0.6%
Puerto Rico Government Development Bank, “B”, 5%, 2015	$	400,000	$	409,484
State of California, 5.25%, 2023		380,000		404,556
			$	814,040
General Obligations – Schools – 0.6%
Irving, TX, Independent School District, “A”, 0%, 2016	$	1,000,000	$	745,110
Healthcare Revenue – Hospitals – 31.5%
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5%, 2028	$	435,000	$	306,923
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5.375%, 2040		625,000		436,231
Atchison, KS Hospital Rev. (Atchison Hospital Assn.), “A”, 6.75%, 2030		320,000		319,817
Brunswick, GA, Hospital Authority Rev. (Glynn-Brunswick Memorial Hospital), 5.625%, 2034		170,000		166,921
California Statewide Communities Development Authority Rev. (Catholic Healthcare West) “K”, ASSD GTY, 5.5%, 2041		625,000		637,200
California Statewide Communities Development Authority Rev. (Catholic Healthcare West) “L”, ASSD GTY, 5.25%, 2041		870,000		871,757
California Statewide Communities Development Authority Rev. (Children’s Hospital), 5%, 2047		290,000		234,088
California Statewide Communities Development Authority Rev. (St. Joseph Health System), FGIC, 5.75%, 2047		635,000		653,180
California Statewide Communities Development Authority Rev. (Sutter Health), “B”, 5.25%, 2048		1,200,000		1,162,956
Cass County, MO, Hospital Rev., 5.625%, 2038		185,000		166,715
Colorado Health Facilities Authority Rev. (National Jewish Medical & Research Center), 5.375%, 2016		1,500,000		1,509,885
Colorado Health Facilities Authority Rev. (Poudre Valley Health Care, Inc.), “B”, FSA, 5.25%, 2036		575,000		570,038
Colorado Health Facilities Authority Rev. (Poudre Valley Health Care, Inc.), “C”, FSA, 5.25%, 2040		520,000		513,682
Conway, AR, Hospital Rev. (Conway Regional Medical Center), “A”, 6.4%, 2029		350,000		352,828
Conway, AR, Hospital Rev. (Conway Regional Medical Center), “B”, 6.4%, 2029		850,000		856,868
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2016 (c)		965,000		1,047,720
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2026 (c)		500,000		545,735
Dickinson County, MI, Healthcare System Hospital Rev., 5.7%, 2018		770,000		762,339
Forsyth County, GA, Hospital Authority Rev. (Baptist Health Care System), ETM, 6%, 2008 (c)		170,000		170,565
Garden City, MI, Hospital Finance Authority Rev. (Garden City Hospital), 5%, 2038		500,000		360,845
Genesee County, NY, Industrial Development Agency Civic Facility Rev. (United Memorial Medical Center), 5%, 2027		90,000		75,898
Glendale, AZ, Industrial Development Authority (John C. Lincoln Health), 5%, 2042		90,000		74,945
Harris County, TX, Cultural Education Facilities Rev. (Baylor College of Medicine), “D”, 5.625%, 2032		280,000		274,000
Highland County, OH, Joint Township, Hospital District Facilities Rev., 6.75%, 2029 (c)		670,000		715,305
Idaho Health Facilities Authority Rev. (IHC Hospitals, Inc.), ETM, 6.65%, 2021 (c)		2,750,000		3,370,345
Illinois Finance Authority Rev. (Children’s Memorial Hospital), “A”, ASSD GTY, 5.25%, 2047		870,000		851,608
Illinois Finance Authority Rev. (Edward Hospital), AMBAC, 5.5%, 2040		1,090,000		1,090,730

1

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue – Hospitals – continued
Illinois Finance Authority Rev. (Kewanee Hospital), 5.1%, 2031	$	425,000	$	341,220
Illinois Health Facilities Authority Rev. (Swedish American Hospital), 6.875%, 2030 (c)		500,000		537,840
Indiana Health & Educational Facilities Authority, Hospital Rev. (Community Foundation of Northwest Indiana), 5.5%, 2037		1,125,000		961,875
Indiana Health & Educational Facilities Financing Authority Rev. (Sisters of St. Francis Health Services, Inc.), FSA, 5.25%, 2041		660,000		659,947
Indiana Health Facilities Financing Authority Rev. (Community Foundation of Northwest Indiana ), “A”, 6%, 2034		425,000		406,330
Jackson, TN, Town Hospital Rev. (Jackson-Madison County General Hospital), 5.75%, 2041		435,000		429,928
Johnson City, TN, Health & Educational Facilities Board Hospital Rev., 5.5%, 2031		1,120,000		1,022,280
Johnson City, TN, Health, Educational Facilities Board & Hospital Rev. (Mountain States Health), “A”, 5.5%, 2036		220,000		197,809
Lake County, OH, Hospital Facilities Rev. (Lake Hospital Systems, Inc.), 5.625%, 2029		435,000		413,193
Louisiana Public Facilities Authority Hospital Rev. (Lake Charles Memorial Hospital), 6.375%, 2034		830,000		774,539
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2032		60,000		54,362
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2037		60,000		53,380
Maryland Health & Higher Educational Facilities Authority Rev. (Medstar Health), BHAC, 5.25%, 2046		440,000		443,568
Maryland Health & Higher Educational Facilities Authority Rev. (Washington County Hospital), 5.75%, 2038		80,000		76,086
Maryland Health & Higher Educational Facilities Authority Rev. (Washington County Hospital), 6%, 2043		120,000		117,259
Massachusetts Development Finance Agency (Boston Biomedical Research), 5.65%, 2019		620,000		622,176
Massachusetts Health & Educational Facilities Authority Rev. (Civic Investments, Inc.), “A”, 9%, 2015 (c)		750,000		902,483
Massachusetts Health & Educational Facilities Authority Rev. (Jordan Hospital), “E”, 6.75%, 2033		250,000		243,508
Massachusetts Health & Educational Facilities Authority Rev. (Milford-Whitinsville Hospital), “C”, 5.25%, 2018		500,000		494,665
Massachusetts Health & Educational Facilities Authority Rev. (Milford-Whitinsville Hospital), “D”, 6.35%, 2032 (c)		250,000		284,325
Massachusetts Health & Educational Facilities Authority Rev. (Quincy Medical Center), “A”, 6.5%, 2038		340,000		327,070
Miami County, OH, Hospital Facilities Rev. (Upper Valley Medical Center), 5.25%, 2018		300,000		297,729
Michigan State Hospital Finance Authority (McLaren Health Care), 5.75%, 2038		870,000		863,014
Minneapolis & St. Paul Redevelopment Authority Rev. (HealthPartners), 5.625%, 2022		200,000		200,384
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2031		125,000		109,193
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2036		620,000		529,009
New Hampshire Health & Educational Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2032 (c)		175,000		198,079
New Hampshire Health & Educational Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2032		25,000		25,076
New Hampshire Health & Educational Facilities Authority Rev. (Memorial Hospital at Conway), 5.25%, 2021		530,000		506,707
New Jersey Health Care Facilities, Financing Authority Rev. (St. Peter’s University Hospital), 5.75%, 2037		545,000		514,284
New Mexico State Hospital Equipment Loan Council, Hospital Rev. (Rehoboth McKinley Christian Hospital), “A”, 5%, 2017		285,000		264,919
Orange County, FL, Health Facilities Authority Hospital Rev. (Orlando Regional Healthcare), 5.75%, 2032 (c)		150,000		167,447

2

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue – Hospitals – continued
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Hospital), “A”, 5.5%, 2030	$	480,000	$	435,797
Salida, CO, Hospital District Rev., 5.25%, 2036		735,000		587,655
Saline County, MO, Industrial Development Authority Rev. (John Fitzgibbon Memorial Hospital, Inc.), 5.625%, 2035		985,000		840,067
Skagit County, WA, Public Hospital District No. 001, 5.75%, 2032		90,000		84,730
South Dakota Health & Educational Facilities Authority Rev. (Sioux Valley Hospitals & Health Systems), “A”, 5.25%, 2034		525,000		508,284
South Lake County, FL, Hospital District Rev. (South Lake Hospital, Inc.), 6.375%, 2034		250,000		250,680
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.375%, 2015		500,000		506,705
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.5%, 2020		550,000		548,554
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.125%, 2026		500,000		455,890
St. Paul, MN, Port Authority Lease Rev. (Regions Hospital), “1”, 5%, 2036		700,000		572,446
Sullivan County, TN, Health, Educational & Housing Facilities Board Hospital Rev. (Wellmont Health Systems Project), “C”, 5.25%, 2036		1,085,000		936,019
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.25%, 2032		230,000		200,468
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.375%, 2037		190,000		163,510
Tyler, TX, Health Facilities Development Corp. (Mother Frances Hospital), 6%, 2031 (c)		750,000		838,763
West Contra Costa, CA, Healthcare District, AMBAC, 5.5%, 2029		105,000		98,233
West Orange, FL, Healthcare District, “A”, 5.65%, 2022		400,000		406,656
West Virginia Hospital Finance Authority Rev. (Charleston Medical Center), 6.75%, 2030 (c)		605,000		663,770
Wisconsin Health & Educational Facilities Authority Rev. (Aurora Health Care, Inc.), 6.4%, 2033		350,000		356,104
Wisconsin Health & Educational Facilities Authority Rev. (Fort Healthcare, Inc.), 6.1%, 2034		750,000		754,553
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Healthcare), 5.75%, 2030 (c)		450,000		498,983
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), 5.25%, 2034		935,000		776,882
			$	41,623,557
Healthcare Revenue – Long Term Care – 31.0%
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement), “A”, 5.9%, 2025	$	750,000	$	704,467
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement), “A”, 7%, 2033		200,000		200,668
Boston, MA, Industrial Development Financing Authority Rev. (Springhouse, Inc.), 5.875%, 2020		235,000		232,905
Bucks County, PA, Industrial Development Authority Retirement Community Rev. (Ann’s Choice, Inc.), “A”, 6.25%, 2035		250,000		241,227
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2027		90,000		81,131
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2037		120,000		102,128
Bucks County, PA, Industrial Development Authority, Retirement Community Rev. (Ann’s Choice, Inc.), 6.125%, 2025		500,000		495,120
California Statewide Communities Development Authority Rev. (Eskaton Properties, Inc.), 8.25%, 2031 (c)		700,000		792,050
Capital Projects Finance Authority, FL (Glenridge on Palmer Ranch), “A”, 8%, 2032 (c)		500,000		592,765
Carlton, MN, Health & Housing Facilities Rev. (Inter-Faith Social Services, Inc.), 7.5%, 2019 (c)		235,000		255,663
Chartiers Valley, PA, Industrial & Commercial Development Authority (Friendship Village), “A”, 5.75%, 2020		1,000,000		1,002,150

3

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue – Long Term Care – continued
Chartiers Valley, PA, Industrial & Commercial Development Authority Rev. (Asbury Health Center), 6.375%, 2024	$	1,000,000	$	997,370
Cole County, MO, Industrial Development Authority, Senior Living Facilities Rev. (Lutheran Senior Services), 5.5%, 2035		750,000		688,522
Colorado Health Facilities Authority Rev. (American Housing Foundation, Inc.), 8.5%, 2031		530,000		532,698
Colorado Health Facilities Authority Rev. (Christian Living Communities Project), “A”, 5.75%, 2037		500,000		432,680
Colorado Health Facilities Authority Rev. (Covenant Retirement Communities, Inc.), 5%, 2035		1,100,000		898,887
Columbus, GA, Housing Authority Rev. (Calvary Community, Inc.), 7%, 2019		450,000		426,573
Connecticut Development Authority Rev. (Elim Park Baptist Home, Inc.), 5.85%, 2033		430,000		408,250
Fulton County, GA, Residential Care Facilities (Canterbury Court), “A”, 6.125%, 2026		500,000		479,575
Fulton County, GA, Residential Care Facilities, First Mortgage (Lenbrook Square Foundation, Inc.), “A”, 5%, 2029		1,500,000		1,205,715
HFDC of Central Texas, Inc., Retirement Facilities Rev. (Legacy at Willow Bend), “A”, 5.75%, 2036		600,000		499,326
Houston, TX, Health Facilities Development Corp., (Buckingham Senior Living Community), “A”, 7%, 2026 (c)		500,000		599,870
Howard County, MD, Retirement Facilities Rev. (Vantage House Corp.), “A”, 5.25%, 2033		200,000		159,600
Huntington, NY, Housing Authority Rev. (Gurwin Senior Jewish Residences), “A”, 5.875%, 2019		420,000		405,938
Huntington, NY, Housing Authority Rev. (Gurwin Senior Jewish Residences), “A”, 6%, 2029		650,000		597,389
Illinois Finance Authority Rev. (Smith Village), “A”, 6.25%, 2035		1,000,000		908,100
Illinois Health Facilities Authority Rev. (Lutheran Senior Ministries, Inc.), 7.375%, 2031 (c)		650,000		743,717
Illinois Health Facilities Authority Rev. (Smith Crossing), “A”, 7%, 2032		525,000		525,604
Indiana Health Facilities Financing Authority Rev. (Hoosier Care, Inc.), 7.125%, 2034		1,015,000		952,019
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), 9.25%, 2025 (c)		915,000		1,084,284
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2018		550,000		537,856
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2028		1,475,000		1,316,393
James City County, VA, Economic Development (Virginia United Methodist Homes, Inc.), “A”, 5.5%, 2037		520,000		412,100
Johnson City, TN, Health & Educational Facilities Board (Appalachian Christian Village), “A”, 6.25%, 2032		250,000		226,415
Juneau, AK, City & Borough Non-Recourse Rev. (St. Ann’s Care Project), 6.875%, 2025		925,000		874,541
Kent County, DE, Assisted Living (Heritage at Dover LLC), 7.625%, 2030		1,140,000		1,003,930
Kentucky Economic Development Finance Authority Health Facilities Rev. (AHF/Kentucky-IOWA, Inc.), 6.5%, 2029		395,000		430,866
Kentwood, MI, Economic Development Ltd. (Holland Home), “A”, 5.375%, 2036		750,000		652,763
La Verne, CA, COP (Brethren Hillcrest Homes), “B”, 6.625%, 2025		525,000		533,626
Lancaster, PA, Industrial Development Authority Rev. (Garden Spot Village), “A”, 7.625%, 2031 (c)		325,000		357,861
Lee County, FL, Industrial Development Authority Health Care Facilities Rev. (Shell Point Village), “A”, 5.5%, 2029 (c)		400,000		420,520
Manhattan, KS, Health Care Facilities Rev. (Meadowlark Hills Retirement Foundation), “A”, 6.375%, 2020 (c)		250,000		260,118
Massachusetts Development Finance Agency Rev. (Adventcare), “A”, 6.75%, 2037		695,000		636,620
Massachusetts Development Finance Agency Rev. (Alliance Health of Brockton, Inc.), “A”, 7.1%, 2032		1,080,000		1,036,822
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.5%, 2027		185,000		163,377
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.75%, 2035		45,000		38,975

4

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue – Long Term Care – continued
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 5.625%, 2015	$	250,000	$	251,548
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 6.9%, 2032		125,000		125,791
Massachusetts Industrial Finance Agency Rev. (GF/Massachusetts, Inc.), 8.3%, 2023		780,000		700,456
Metropolitan Government of Nashville & Davidson County, TN, Health & Educational Facilities Board Rev. (Blakeford at Green Hills), 5.65%, 2024		575,000		522,842
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.125%, 2028		150,000		136,466
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.25%, 2035		600,000		535,590
New Hampshire Higher Education & Health Facilities Authority Rev. (Rivermead at Peterborough Retirement Community), 5.75%, 2028		1,100,000		990,594
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.75%, 2025		400,000		370,428
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.875%, 2037		300,000		263,940
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2026		500,000		434,780
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2036		500,000		407,535
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), “A”, 8.25%, 2030 (c)		700,000		796,502
New Jersey Economic Development Authority Rev. (Seashore Gardens), 5.375%, 2036		350,000		282,233
North Carolina Medical Care Commission, First Mortgage (DePaul Community Facilities, Inc.), 7.625%, 2029 (c)		980,000		1,049,482
Roseville, MN, Elder Care Facilities (Care Institute, Inc.), 7.75%, 2023		1,630,000		1,433,683
Sartell, MN, Health Care & Housing Authority Rev. (The Foundation for Health Care), “A”, 6.625%, 2029		1,025,000		989,576
Savannah, GA, Economic Development Authority, First Mortgage (Marshes of Skidway), “A”, 7.4%, 2034		350,000		351,120
Shelby County, TN, Health, Educational & Housing Facilities Board Rev. (Germantown Village), “A”, 7.25%, 2034		300,000		280,059
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2027		280,000		259,538
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2042		260,000		224,866
South Carolina Jobs & Economic Development Authority, Health Facilities Rev. (Wesley Commons), 5.3%, 2036		200,000		163,904
St. Johns County, FL, Industrial Development Authority (Glenmoor Project), “A”, 5.25%, 2026		500,000		425,380
Westmoreland County, PA, Industrial Development Authority Rev. (Redstone Retirement Community), “A”, 5.875%, 2032		600,000		521,028
Westmoreland County, PA, Industrial Development Retirement Authority Rev. (Redstone Retirement Community), “A”, 5.75%, 2026		1,250,000		1,137,550
Wisconsin Health & Educational Facilities Authority Rev. (Attic Angel Community, Inc.), 5.75%, 2027 (c)		875,000		899,701
Wisconsin Health & Educational Facilities Authority Rev. (Clement Manor, Inc.), 5.75%, 2024		1,000,000		938,430
Wisconsin Health & Educational Facilities Board Rev. (All Saints Assisted Living Project), 5.9%, 2027		90,000		83,583
Wisconsin Health & Educational Facilities Board Rev. (All Saints Assisted Living Project), 6%, 2037		185,000		166,983
			$	40,892,762
Industrial Revenue – Airlines – 3.9%
Alliance Airport Authority, TX (American Airlines, Inc.), 5.25%, 2029	$	1,640,000	$	946,149
Chicago, IL, O’Hare International Airport Special Facilities Rev. (American Airlines, Inc.), 5.5%, 2030		1,745,000		1,045,970

5

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PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue – Airlines – continued
Cleveland, OH, Airport Special Rev. (Continental Airlines, Inc.), 5.7%, 2019	$	875,000	$	706,239
Dallas Fort Worth, TX, International Airport Facility Improvement Corp. (American Airlines, Inc.), 5.5%, 2030		750,000		442,080
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 9%, 2033 (a)		1,250,000		1,254,050
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.75%, 2031		365,000		326,317
New York, NY, City Industrial Development Agency Special Facility Rev. (American Airlines, Inc.), “B”, 8.5%, 2028		500,000		488,705
			$	5,209,510
Industrial Revenue – Chemicals – 0.3%
Brazos River, TX, Harbor Navigation District (Dow Chemical Co.), “B-2”, 4.95%, 2033	$	400,000	$	337,172
Industrial Revenue – Environmental Services – 0.8%
Carbon County, UT, Solid Waste Disposal Rev. (Allied Waste Industries), “A”, 7.5%, 2010	$	250,000	$	251,747
Carbon County, UT, Solid Waste Disposal Rev. (Laidlaw Environmental), “A”, 7.45%, 2017		500,000		500,850
Gulf Coast Waste Disposal Authority, TX (Waste Management of Texas), “A”, 5.2%, 2028		360,000		299,358
			$	1,051,955
Industrial Revenue – Metals – 0.4%
Director of Nevada Department of Business & Industry (Wheeling/Pittsburgh Steel), “A”, 8%, 2014	$	150,000	$	150,508
Greensville County, VA, Industrial Development Authority Rev. (Wheeling/Pittsburgh Steel), “A”, 7%, 2014		435,000		423,855
			$	574,363
Industrial Revenue – Other – 4.0%
Annawan, IL, Tax Increment Rev. (Patriot Renewable Fuels LLC), 5.625%, 2018	$	350,000	$	327,173
California Statewide Communities Development Authority Facilities (Microgy Holdings Project), 9%, 2038		400,000		399,900
Gulf Coast, TX, Industrial Development Authority Rev. (CITGO Petroleum Corp.), 8%, 2028		375,000		388,920
Houston, TX, Industrial Development Corp. (United Parcel Service, Inc.), 6%, 2023		475,000		439,085
Indianapolis, IN, Airport Authority Rev., Special Facilities (FedEx Corp.), 5.1%, 2017		500,000		472,760
Michigan Strategic Fund Rev. (Michigan Sugar Co.), “A”, 6.25%, 2015		1,000,000		1,006,900
New Jersey Economic Development Authority Rev. (GMT Realty LLC), “B”, 6.875%, 2037		1,000,000		973,750
Virgin Islands Government Refinery Facilities Rev. (Hovensa Coker Project), 6.5%, 2021		250,000		250,995
Virgin Islands Public Finance Authority, Refinery Facilities Rev. (Hovensa Coker Project), 5.875%, 2022		400,000		379,476
Will-Kankakee, IL, Regional Development Authority Rev. (Flanders Corp.), 6.5%, 2017		655,000		646,858
			$	5,285,817
Industrial Revenue – Paper – 3.5%
Beauregard Parish, LA (Boise Cascade Corp.), 6.8%, 2027	$	1,000,000	$	990,610
Bedford County, VA, Industrial Development Authority Rev. (Nekooska Packaging Corp.), 5.6%, 2025		400,000		312,536
Camden, AL, Industrial Development Board Exempt Facilities Rev., “B” (Weyerhaeuser Co.), 6.375%, 2024		400,000		456,460
Courtland AL, Industrial Development Board Solid Waste Disposal Rev. (Champion International Corp.), 6%, 2029		1,000,000		905,280
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 4.75%, 2030		290,000		216,508
Escambia County, FL, Environmental Improvement Rev. (International Paper Co., Projects), “A”, 5%, 2026		980,000		785,107

6

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue – Paper – continued
Lowndes County, MS, Solid Waste Disposal & Pollution Control Rev. (Weyerhaeuser Co.), “B”, 6.7%, 2022	$	595,000	$	609,363
Phenix City, AL, Industrial Development Board Environmental Improvement Rev., “A” (MeadWestvaco Coated), 6.35%, 2035		400,000		371,444
			$	4,647,308
Miscellaneous Revenue – Entertainment & Tourism – 2.7%
Agua Caliente Band of Cahuilla Indians, CA, 5.6%, 2013 (z)	$	775,000	$	795,258
Cabazon Band Mission Indians, CA, 8.375%, 2015 (z)		150,000		155,380
Cabazon Band Mission Indians, CA, 8.75%, 2019 (z)		720,000		748,627
Cow Creek Band of Umpqua Tribe of Indians, OR, “C”, 5.625%, 2026 (n)		650,000		578,610
Mashantucket Western Pequot Tribe, CT, “B”, 0%, 2018 (n)		1,100,000		621,291
New York Liberty Development Corp. Rev. (National Sports Museum), “A”, 6.125%, 2019		400,000		354,528
Seminole Tribe, FL, Special Obligation, “A”, 5.25%, 2027 (n)		280,000		258,409
			$	3,512,103
Miscellaneous Revenue – Other – 1.1%
Austin, TX, Convention Center (Convention Enterprises, Inc.), XLCA, 5.25%, 2024	$	115,000	$	108,070
Capital Trust Agency, FL (Aero Syracuse LLC), 6.75%, 2032		350,000		328,905
Philadelphia, PA, Industrial Development Airport Rev. (Aero Philadelphia LLC), 5.25%, 2009		95,000		94,844
Summit County, OH, Port Authority Building Rev. (Twinsburg Township), “D”, 5.125%, 2025		655,000		614,600
V Lakes Utility District Ranking Water Systems Rev., 7%, 2037		300,000		267,888
			$	1,414,307
Multi-Family Housing Revenue – 7.5%
Broward County, FL, Housing Finance Authority Rev. (Chaves Lakes Apartments Ltd.), “A”, 7.5%, 2040	$	500,000	$	508,190
Capital Trust Agency, FL, Housing Rev. (Atlantic Housing Foundation), 7%, 2032		650,000		650,000
Charter Mac Equity Issuer Trust, FHLMC, 6%, 2019 (n)		1,000,000		1,058,020
Charter Mac Equity Issuer Trust, “B”, FHLMC, 7.6%, 2010 (a)(n)		500,000		538,915
Clay County, FL, Housing Finance Authority Rev. (Madison Commons Apartments), “A”, 7.45%, 2040		495,000		499,658
District of Columbia Housing Finance Agency (Henson Ridge), FHA, 5.1%, 2037		655,000		583,160
Durham, NC, Durham Housing Authority Rev. (Magnolia Pointe Apartments), 5.65%, 2038 (a)		996,790		873,886
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “D”, 10%, 2032		295,000		296,316
El Paso County, TX, Housing Finance Corp. (American Housing Foundation, Inc.), “C”, 8%, 2032		290,000		291,386
Massachusetts Housing Finance Agency Rev., “B”, 5%, 2030		500,000		478,125
Massachusetts Housing Finance Agency Rev., “E”, 5%, 2028		500,000		459,830
Mississippi Home Corp., Rev. (Kirkwood Apartments), 6.8%, 2037		605,000		567,018
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049 (n)		1,000,000		994,310
New Mexico Mortgage Finance Authority, Multi-Family Housing Rev. (Sun Pointe Apartments), “E”, FHA, 4.8%, 2040		500,000		418,795
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016 (z)		455,481		448,526
Seattle, WA, Housing Authority Rev., Capped Fund Program (High Rise Rehab), “I”, FSA, 5%, 2025		500,000		467,650
Wilmington, DE, Multi-Family Housing Rev. (Electra Arms Senior Associates), 6.25%, 2028		850,000		762,195
			$	9,895,980
Sales & Excise Tax Revenue – 5.2%
Bolingbrook, IL, Sales Tax Rev., 6.25%, 2024	$	500,000	$	504,135
Metropolitan Pier & Exposition Authority, State Tax Rev., FGIC, 0%, 2014		3,990,000		3,202,454
Metropolitan Pier & Exposition Authority, State Tax Rev., MBIA, 0%, 2015		3,000,000		2,301,120

7

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Sales & Excise Tax Revenue – continued
Metropolitan Pier & Exposition Authority, State Tax Rev., ETM, FGIC, 0%, 2014 (c)	$	1,010,000	$	824,099
			$	6,831,808
Single Family Housing – Local – 1.2%
Minneapolis & St. Paul Housing Authority Rev. (City Living), “A-2”, GNMA, 5%, 2038	$	733,948	$	610,777
Pittsburgh, PA, Urban Redevelopment Authority Rev., “C”, GNMA, 4.8%, 2028		1,000,000		937,190
			$	1,547,967
Single Family Housing – State – 0.3%
Kentucky Counties Single Family Mortgage Rev., “A”, MBIA, 9%, 2016	$	5,000	$	5,009
North Dakota Housing Finance Agency Rev., “A”, 4.85%, 2021		475,000		443,113
			$	448,122
Solid Waste Revenue – 0.7%
Delaware County, PA, Industrial Development Authority, Resource Recovery Facilities Rev. (American Ref-Fuel Co.), “A”, 6.2%, 2019	$	1,000,000	$	978,340
State & Agency – Other – 0.4%
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.25%, 2024	$	100,000	$	97,039
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.5%, 2037		500,000		466,160
			$	563,199
State & Local Agencies – 2.7%
Dorchester County, SC, School District No. 2, Growth Remedy Opportunity Tax Hike, 5.25%, 2029	$	500,000	$	497,425
Laurens County, SC, School District No. 55, Installment Purchase Rev., 5.25%, 2030		700,000		664,734
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024		1,000,000		1,011,140
Newberry, SC, Investing in Children’s Education (Newberry County School District Program), 5%, 2030		400,000		368,884
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026 (c)		80,000		91,234
Puerto Rico Public Finance Corp., Unrefunded, “E”, 6%, 2026		820,000		935,153
			$	3,568,570
Tax – Other – 1.0%
Dallas County, TX, Flood Control District, 7.25%, 2032	$	750,000	$	773,992
New Jersey Economic Development Authority Rev. (Cigarette Tax), 5.75%, 2029		500,000		473,235
New Jersey Economic Development Authority Rev. (Cigarette Tax), 5.5%, 2031		120,000		108,712
			$	1,355,939
Tax Assessment – 14.8%
Atlanta, GA, Tax Allocation (Eastside Project), “B”, 5.4%, 2020	$	500,000	$	466,590
Ave Maria Stewardship Community District, FL, “A”, 5.125%, 2038		150,000		110,765
Celebration Community Development District, FL, “A”, 6.4%, 2034		710,000		725,769
Channing Park Community Development District, FL, 5.3%, 2038		400,000		301,128
Chicago, IL, Tax Increment Allocation (Pilsen Redevelopment), “B”, 6.75%, 2022		310,000		318,243
Colonial Country Club Community Development District, FL, 6.4%, 2033		475,000		482,362
Double Branch Community Development District, FL, “A”, 6.7%, 2034		480,000		488,966
Du Page County, IL, Special Service Area No. 31 Special Tax (Monarch Landing Project), 5.625%, 2036		250,000		209,622
Durbin Crossing Community Development District, FL, Special Assessment, “B-1”, 4.875%, 2010		225,000		215,080
Grand Bay at Doral Community Development District, FL, “A”, 6%, 2039		90,000		75,362
Grand Bay at Doral Community Development District, FL, “B”, 6%, 2017		545,000		502,348
Heritage Harbour North Community Development District, FL, Capital Improvement Rev., 6.375%, 2038		325,000		287,622
Homestead 50 Community Development District, FL, “A”, 6%, 2037		375,000		314,393
Homestead 50 Community Development District, FL, “B”, 5.9%, 2013		170,000		161,364
Huntington Beach, CA, Community Facilities District, Special Tax (Grand Coast Resort), “2000-1”, 6.45%, 2031		500,000		507,860
Islands at Doral Southwest Community Development District, FL, 6.375%, 2035 (c)		245,000		276,561
Lexington Oaks Community Development District, FL, “A”, 6.125%, 2019 (c)		615,000		619,342

8

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tax Assessment – continued
Lincoln, CA, Special Tax (Community Facilities District ), “2003-1”, 5.55%, 2018 (c)	$	440,000	$	500,122
Lincolnshire, IL, Special Service Area No. 1 (Sedgebrook Project), 6.25%, 2034		250,000		231,483
Magnolia Park Community Development District, FL, Special Assessment Rev., “A”, 6.15%, 2039		630,000		541,693
Main Street Community Development District, FL, “A”, 6.8%, 2038		295,000		288,351
Main Street Community Development District, FL, “B”, 6.9%, 2017		225,000		223,099
Northwest Metropolitan District No. 3, CO, 6.25%, 2035		500,000		418,775
Oakdale, CA, Public Financing Authority Tax Allocation Rev. (Central City Redevelopment Project), 5.375%, 2033		1,125,000		1,047,150
Oakmont Grove Community Development District, CA, “A”, 5.4%, 2038		300,000		216,405
Ohio County, WV, Commission Tax Increment Rev. (Fort Henry Centre), “A”, 5.85%, 2034		125,000		116,963
Orange County, CA, Community Facilities Tax No 99, (Ladera Ranch), “A”, 6.5%, 2021 (c)		1,000,000		1,064,780
Orange County, CA, Improvement Act 1915, “B”, 5.75%, 2033		500,000		462,655
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.5%, 2010		45,000		44,590
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.8%, 2026		300,000		289,695
Plano, IL, Special Service Area No. 4 (Lakewood Springs Project Unit 5-B), 6%, 2035		1,500,000		1,365,450
Pontiac, MI, Tax Increment Finance Authority Rev., 6.375%, 2031 (c)		450,000		509,598
Portage, IN, Economic Development Rev. (Ameriplex Project), 5%, 2027		260,000		234,603
Redwood City, CA, Special Tax Community Facilities, (District 1 Redwood), “B”, 6%, 2033		300,000		293,541
San Diego, CA, Redevelopment Agency, Tax Allocation, FSA, 0%, 2018		1,015,000		658,349
Sarasota National Community Development District, FL, Special Assessment Rev., 5.3%, 2039		800,000		592,048
Seven Oaks, FL, Community Development District II Special Assessment Rev., “B”, 5%, 2009		580,000		572,593
Sweetwater Creek Community Development District, FL, Capital Improvement Rev., 5.5%, 2038		200,000		147,640
Tolomato Community Development District, FL, Special Assessment Rev., 6.65%, 2040		585,000		565,479
Tuscany Reserve Community Development District, FL, Special Assessment, “B”, 5.25%, 2016		185,000		159,699
Volo Village, IL, Special Service Area No. 3, Special Tax (Symphony Meadows Project), “1”, 6%, 2036		484,000		429,027
West Villages Improvement District, FL, Special Assessment Rev. (Unit of Development No. 3), 5.5%, 2037		495,000		388,530
Westchester, FL, Community Development District No. 1 (Community Infrastructure), 6.125%, 2035		275,000		234,413
Westridge, FL, Community Development District, Capital Improvement Rev., 5.8%, 2037		980,000		801,326
Wyandotte County-Kansas City, KS, Unified Government Transportation Development District (Legends Village West Project), 4.875%, 2028		585,000		494,869
Yorba Linda, CA, Redevelopment Agency, Tax Allocation Rev., “A”, MBIA, 0%, 2024		1,325,000		571,327
			$	19,527,630
Tobacco – 9.8%
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 5.875%, 2030	$	1,610,000	$	1,391,153
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 5.875%, 2047		2,810,000		2,275,959
Buckeye, OH, Tobacco Settlement Rev., Asset Backed, “A-2”, 6.5%, 2047		785,000		693,131
California County, CA, Tobacco Securitization Agency, Tobacco Settlement Rev. (Los Angeles County), 0%, 2046		3,500,000		156,800
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 6.25%, 2033 (c)		1,495,000		1,634,020
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, “A-1”, 5.125%, 2047		1,135,000		840,649

9

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tobacco – continued
Inland Empire, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, “C-1”, 0%, 2036	$	1,815,000	$	203,244
Michigan Tobacco Settlement Finance Authority Rev., Asset Backed, “A”, 6%, 2048		1,710,000		1,419,899
Rhode Island Tobacco Settlement Authority, 6%, 2023		2,115,000		2,091,735
Tobacco Settlement Authority of Washington Rev., Asset Backed, 6.625%, 2032		500,000		494,880
Tobacco Settlement Financing Corp., NJ, 6.75%, 2039 (c)		1,000,000		1,168,870
Virginia Tobacco Settlement Financing Corp., “B-1”, 5%, 2047		830,000		588,155
			$	12,958,495
Toll Roads – 4.9%
E-470 Public Highway Authority, CO, “B”, MBIA, 0%, 2018	$	3,000,000	$	1,836,930
E-470 Public Highway Authority, CO, “B”, 0%, 2035 (c)		8,750,000		1,264,813
Northwest Parkway, CO, Public Highway Authority (First Tier), “D”, 7.125%, 2041 (c)		995,000		1,129,434
San Joaquin Hills, CA, Transportation Corridor Agency Toll Road Rev., “A”, MBIA, 0%, 2015		3,000,000		2,278,470
			$	6,509,647
Universities – Colleges – 15.7%
California Municipal Finance Authority Rev. (Biola University), 5.8%, 2028	$	100,000	$	99,877
University of Virginia Rev., 11.98%, 2040 (u)		20,000,000		20,384,800
West Virginia University Rev. (West Virginia University Project), “A”, AMBAC, 0%, 2025		750,000		311,603
			$	20,796,280
Universities – Dormitories – 0.8%
California Statewide Communities Development Authority Rev. (Lancer Educational Student Housing Project), 5.625%, 2033	$	735,000	$	654,650
Minneapolis, MN, Student Housing Rev. (Riverton Community Housing Project), “A”, 5.7%, 2040		500,000		441,570
			$	1,096,220
Universities – Secondary Schools – 1.4%
California Statewide Communities Development Authority Rev., COP, (Crossroads Schools for the Arts & Sciences), 6%, 2028	$	1,010,000	$	1,036,482
Colorado Housing Finance Development Rev. (Evergreen Country Day School), 5.875%, 2037		425,000		376,078
Lee County, FL, Industrial Development Authority Rev. (Lee Charter Foundation), “A”, 5.375%, 2037		535,000		426,893
			$	1,839,453
Utilities – Cogeneration – 1.8%
Port Authority NY & NJ, Special Obligation Rev., 6.75%, 2011	$	1,500,000	$	1,501,620
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Central Facilities (Cogeneration Facilities - AES Puerto Rico Project), 6.625%, 2026		320,000		331,421
Suffolk County, NY, Industrial Development Agency Rev. (Nissequoque Cogeneration Partners Facilities), 5.5%, 2023		550,000		503,008
			$	2,336,049
Utilities – Investor Owned – 4.8%
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 5.75%, 2036 (a)	$	220,000	$	204,950
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 6.75%, 2038		555,000		452,558
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “D”, 5.4%, 2029 (a)		45,000		39,710
Bryant, IL, Pollution Control Rev. (Central Illinois Light Co.), 5.9%, 2023		1,000,000		1,001,670
Clark County, NV, Industrial Development Rev. (Nevada Power Co. Project), “A”, 5.9%, 2032		1,500,000		1,302,600
Mississippi Business Finance Corp., Pollution Control Rev. (Systems Energy Resources Project), 5.875%, 2022		1,500,000		1,471,770

10

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Utilities – Investor Owned – continued
New Hampshire Business Finance Authority, Pollution Control Rev. (Public Service of New Hampshire), “B”, MBIA, 4.75%, 2021	$	250,000	$	244,175
Pennsylvania Economic Development Financing Authority Rev. (Reliant Energy Seward), “A”, 6.75%, 2036		400,000		403,344
Red River, TX, Authority Pollution Control (AEP Texas Central Co.), MBIA, 4.45%, 2020		410,000		399,361
Sabine River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), 5.2%, 2028		185,000		133,794
Sabine River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), 5.75%, 2030 (a)		155,000		144,396
West Feliciana Parish, LA, Pollution Control Rev. (Entergy Gulf States), 6.6%, 2028		500,000		496,160
			$	6,294,488
Utilities – Municipal Owned – 0.3%
North Carolina Eastern Municipal Power Agency System Rev., “F”, 5.5%, 2016	$	430,000	$	447,557
Utilities – Other – 1.2%
Main Street Natural Gas, Inc. Gas Rev., “B”, 5%, 2019	$	325,000	$	295,870
Main Street Natural Gas, Inc., GA, Gas Project Rev., “A”, 5.5%, 2028		335,000		288,666
Salt Verde Financial Corp., AZ, Senior Gas Rev., 5%, 2037		705,000		589,317
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2026		165,000		151,191
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2025		240,000		215,602
			$	1,540,646
Water & Sewer Utility Revenue – 1.1%
Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2038	$	655,000	$	683,080
Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2044		135,000		140,058
Surprise, AZ, Municipal Property Corp., 4.9%, 2032		700,000		625,968
			$	1,449,106
Total Municipal Bonds			$	211,204,204
Floating Rate Demand Notes – 6.4%
East Baton Rouge, LA, Pollution Control Rev. (Exxon Mobil Corp.), 2%, due 9/02/08	$	2,000,000	$	2,000,000
Jacksonville, FL, Pollution Control Rev. (Florida Power & Light Co.), 2.29%, due 9/02/08		2,500,000		2,500,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), 2%, due 9/02/08		400,000		400,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), “A”, 2.2%, due 9/02/08		300,000		300,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), “B”, 2.2%, due 9/02/08		100,000		100,000
Lincoln County, WY, Pollution Control Rev. (Exxon Mobil Corp.), “C”, 2.2%, due 9/02/08		1,200,000		1,200,000
Mt. Vernon Industrial Pollution Control Rev. (General Electric Co.), 2.27%, due 9/02/08		800,000		800,000
Sublette County, WY, Pollution Control Rev. (Exxon Mobil Corp.), 2%, due 9/02/08		1,100,000		1,100,000
Total Floating Rate Demand Notes			$	8,400,000
Total Investments			$	219,604,204
Other Assets, Less Liabilities – (9.5)%				(12,535,881	)
Preferred shares (issued by the trust) – (56.8)%				(75,000,000	)
Net assets applicable to common shares – 100.0%			$	132,068,323

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

(c) Refunded bond.

(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 $4,049,556 representing 3.1% of net assets.

(u) Underlying security deposited into special purpose trust (“the trust”) by investment banker upon creation of self-deposited inverse floaters.

11

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (Unaudited) 8/31/08 - 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	$	776,074	$	795,258
Cabazon Band Mission Indians, CA, 8.375%, 2015	10/04/04		150,000		155,380
Cabazon Band Mission Indians, CA, 8.75%, 2019	10/04/04		720,000		748,627
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016	10/17/01 - 1/14/02		455,481		448,526
Total Restricted Securities				$	2,147,791
% of Net Assets					1.6	%

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

COP	Certificate of Participation
ETM	Escrowed to Maturity
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) 8/31/08

(1) Fair Value Disclosure

The fund adopted FASB Statement No. 157, Fair Value Measurements (the “Statement”) in this reporting period. 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, which are valued at the unrealized appreciation/depreciation on the instrument. The following is a summary of the levels used as of August 31, 2008 in valuing the fund’s assets or liabilities carried at market value:

	Level 1			Level 2		Level 3		Total
Investments in Securities	$	—		$	219,604,204	$	—	$	219,604,204
Other Financial Instruments	$	(20,382	)	$	—	$	—	$	(20,382	)

(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	$	210,474,673
Gross unrealized appreciation	$	5,782,988
Gross unrealized depreciation		(11,653,457	)
Net unrealized appreciation (depreciation)	$	(5,870,469	)

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

(3) Derivative Contracts

Futures contracts outstanding at 8/31/08

Description	Contracts	Value		Expiration Date	Unrealized Appreciation (Depreciation)
U.S. Treasury Bond (Short)	96	$	11,262,000	Dec-08	$	10,914
U.S. Treasury Note 10 yr (Short)	424		48,972,000	Dec-08		(31,296	)
					$	(20,382	)

At August 31, 2008, 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)*	ROBERT J. MANNING
	Robert J. Manning, President

Date: October 15, 2008

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)*	ROBERT J. MANNING
	Robert J. Manning, President (Principal Executive Officer)

Date: October 15, 2008

By (Signature and Title)*	MARIA F. DWYER
	Maria F. Dwyer, Treasurer (Principal Financial Officer and Accounting Officer)

Date: October 15, 2008

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