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, 2011

ITEM 1. SCHEDULE OF INVESTMENTS.

MFS^® High Yield Municipal Trust

QUARTERLY REPORT

August 31, 2011

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

Issuer	Shares/Par		Value ($)
Municipal Bonds – 157.5%
Airport Revenue – 3.2%
Dallas Fort Worth, TX, International Airport Rev. Improvement, “B”, AGM, 5%, 2025	$	3,000,000	$	3,046,089
Houston, TX, Airport System Rev., “B”, 5%, 2026		175,000		186,305
Port Authority NY & NJ, Special Obligation Rev. (JFK International Air Terminal LLC), 6%, 2036		255,000		260,776
Port Authority NY & NJ, Special Obligation Rev. (JFK International Air Terminal LLC), 6%, 2042		290,000		294,692
			$	3,787,862
General Obligations - General Purpose – 1.2%
Chicago, IL, Metropolitan Water Reclamation District-Greater Chicago, “C”, 5%, 2030	$	780,000	$	845,629
Luzerne County, PA, AGM, 6.75%, 2023		455,000		520,848
			$	1,366,477
General Obligations - Improvement – 0.1%
Guam Government, “A”, 7%, 2039	$	90,000	$	92,238
General Obligations - Schools – 2.3%
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2029	$	2,195,000	$	844,087
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2031		275,000		91,611
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2032		280,000		86,310
Beverly Hills, CA, Unified School District (Election of 2008), Capital Appreciation, 0%, 2033		560,000		160,759
Irving, TX, Independent School District, Capital Appreciation, “A”, PSF, 0%, 2016		1,000,000		944,490
Los Angeles, CA, Unified School District, “D”, 5%, 2034		165,000		170,927
San Jacinto, TX, Community College District, 5.125%, 2038		430,000		449,273
			$	2,747,457
Healthcare Revenue - Hospitals – 38.0%
Allegheny County, PA, Hospital Development Authority Rev. (University of Pittsburgh Medical Center), “A”, 5.375%, 2029	$	440,000	$	459,188
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5%, 2028		435,000		369,602
Allegheny County, PA, Hospital Development Authority Rev. (West Penn Allegheny Health), “A”, 5.375%, 2040		625,000		530,613
Atchison, KS, Hospital Rev. (Atchison Hospital Assn.), “A”, 6.75%, 2030		320,000		298,346
Brunswick, GA, Hospital Authority Rev. (Glynn-Brunswick Memorial Hospital), 5.625%, 2034		170,000		172,072
Butler County, OH, Hospital Facilities Rev. (UC Health), 5.5%, 2040		590,000		535,301
Butler County, OH, Hospital Facilities Rev. (UC Health), 5.75%, 2040		130,000		122,311
California Health Facilities Financing Authority Rev. (St. Joseph Health System), “A”, 5.75%, 2039		185,000		188,596
California Health Facilities Financing Authority Rev. (Sutter Health), “A”, 5%, 2042		500,000		473,555
California Health Facilities Financing Authority Rev. (Sutter Health), “B”, 5.875%, 2031		660,000		713,559
California Statewide Communities Development Authority Rev. (Catholic Healthcare West), “K”, ASSD GTY, 5.5%, 2041		625,000		637,400
California Statewide Communities Development Authority Rev. (Children’s Hospital), 5%, 2047		290,000		231,788
Cullman County, AL, Health Care Authority (Cullman Regional Medical Center), “A”, 6.75%, 2029		60,000		58,090
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2016 (c)		965,000		1,106,160
Delaware County, PA, Authority Rev. (Mercy Health Corp.), ETM, 6%, 2026 (c)		500,000		582,065
Erie County, PA, Hospital Authority Rev. (St. Vincent’s Health), “A”, 7%, 2027		410,000		415,588

1

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Gage County, NE, Hospital Authority No. 1, Health Care Facilities Rev. (Beatrice Community Hospital & Health Care Center), “B”, 6.75%, 2035	$	195,000	$	198,574
Garden City, MI, Hospital Finance Authority Rev. (Garden City Hospital), 5%, 2038		500,000		352,720
Harris County, TX, Health Facilities Development Corp., Hospital Rev. (Memorial Hermann Healthcare Systems), “B”, 7.25%, 2035		205,000		228,483
Idaho Health Facilities Authority Rev. (IHC Hospitals, Inc.), ETM, 6.65%, 2021 (c)		2,750,000		3,673,643
Illinois Finance Authority Rev. (Kewanee Hospital), 5.1%, 2031		390,000		319,281
Illinois Finance Authority Rev. (Provena Health), “A”, 7.75%, 2034		485,000		543,171
Illinois Finance Authority Rev. (Silver Cross Hospital & Medical Centers), 6.875%, 2038		485,000		500,666
Indiana Health & Educational Facilities Finance Authority Rev. (Sisters of St. Francis Health Services, Inc.), “E”, AGM, 5.25%, 2041		660,000		672,560
Indiana Health & Educational Facilities Finance Authority, Hospital Rev. (Clarian Health), “A”, 5%, 2039		1,745,000		1,633,809
Indiana Health & Educational Facilities Finance Authority, Hospital Rev. (Community Foundation of Northwest Indiana), 5.5%, 2037		945,000		890,738
Indiana Health & Educational Financing Authority Rev. (Community Foundation of Northwest Indiana ), “A”, 6%, 2034		425,000		431,996
Johnson City, TN, Health & Educational Facilities Board Hospital Rev. (Mountain States Health Alliance), “A”, 5.5%, 2031		1,120,000		1,103,962
Johnson City, TN, Health & Educational Facilities Board Hospital Rev. (Mountain States Health Alliance), “A”, 5.5%, 2036		410,000		393,887
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.375%, 2024		300,000		327,396
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Baptist Healthcare System), “A”, 5.625%, 2027		100,000		107,578
Kentucky Economic Development Finance Authority, Hospital Facilities Rev. (Owensboro Medical Health System), “A”, 6.375%, 2040		570,000		584,301
Lake County, OH, Hospital Facilities Rev. (Lake Hospital Systems, Inc.), 5.625%, 2029		435,000		423,255
Lebanon County, PA, Health Facilities Authority Rev. (Good Samaritan Hospital), 5.9%, 2028		210,000		197,461
Louisiana Public Facilities Authority Hospital Rev. (Lake Charles Memorial Hospital), 6.375%, 2034		880,000		822,914
Louisville & Jefferson County, KY, Metro Government Health Facilities Rev. (Jewish Hospital & St. Mary’s Healthcare), 6.125%, 2037		1,315,000		1,327,019
Louisville & Jefferson County, KY, Metropolitan Government Healthcare Systems Rev. (Norton Healthcare, Inc.), 5.25%, 2036		1,265,000		1,217,208
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2032		60,000		54,077
Lufkin, TX, Health Facilities Development Corp. Rev. (Memorial Health System), 5.5%, 2037		60,000		51,586
Maryland Health & Higher Educational Facilities Authority Rev. (Anne Arundel Health System), “A”, 6.75%, 2039		735,000		817,842
Massachusetts Development Finance Agency Rev. (Tufts Medical Center), “I”, 7.25%, 2032		445,000		495,650
Massachusetts Health & Educational Facilities Authority Rev. (Boston Medical Center), 5.25%, 2038		1,000,000		842,190
Massachusetts Health & Educational Facilities Authority Rev. (Jordan Hospital), “E”, 6.75%, 2033		250,000		244,383
Massachusetts Health & Educational Facilities Authority Rev. (Milford-Whitinsville Hospital), “C”, 5.25%, 2018		500,000		483,185
Massachusetts Health & Educational Facilities Authority Rev. (Quincy Medical Center), “A”, 6.5%, 2038		485,000		392,850
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2031		125,000		114,849

2

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Montgomery, AL, Medical Clinic Board Health Care Facility Rev. (Jackson Hospital & Clinic), 5.25%, 2036	$	825,000	$	739,316
New Hampshire Business Finance Authority Rev. (Elliot Hospital Obligated Group), “A”, 6%, 2027		585,000		584,374
New Hampshire Health & Education Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2012 (c)		175,000		184,977
New Hampshire Health & Education Facilities Authority Rev. (Catholic Medical Center), “A”, 6.125%, 2032		25,000		25,110
New Hampshire Health & Educational Facilities Authority Rev. (Memorial Hospital at Conway), 5.25%, 2021		530,000		511,551
New Hanover County, NC, Hospital Rev., AGM, 5.125%, 2031		895,000		928,795
New Jersey Health Care Facilities, Financing Authority Rev. (St. Peter’s University Hospital), 5.75%, 2037		545,000		515,570
New Mexico Hospital Equipment Loan Council, Hospital Rev. (Rehoboth McKinley Christian Hospital), “A”, 5%, 2017		245,000		233,720
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.5%, 2030		190,000		207,769
New York Dormitory Authority Rev., Non-State Supported Debt (Bronx-Lebanon Hospital Center), LOC, 6.25%, 2035		115,000		123,911
Norman, OK, Regional Hospital Authority Rev., 5%, 2027		155,000		127,793
Norman, OK, Regional Hospital Authority Rev., 5.375%, 2029		90,000		75,572
Norman, OK, Regional Hospital Authority Rev., 5.375%, 2036		235,000		184,926
Norman, OK, Regional Hospital Authority Rev., 5.125%, 2037		415,000		311,308
North Carolina Medical Care Commission Health Care Facilities Rev. (Novant Health), “A”, 4.75%, 2043		905,000		785,440
Olympia, WA, Healthcare Facilities Authority Rev. (Catholic Health Initiatives), “D”, 6.375%, 2036		1,095,000		1,196,627
Orange County, FL, Health Facilities Authority Hospital Rev. (Orlando Regional Healthcare), 5.75%, 2012 (c)		150,000		159,846
Palomar Pomerado Health Care District, CA, COP, 6.75%, 2039		890,000		898,767
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Health System), “A”, 6.625%, 2023		375,000		370,485
Philadelphia, PA, Hospitals & Higher Education Facilities Authority Rev. (Temple University Health System), “A”, 5.5%, 2030		395,000		352,423
Rhode Island Health & Educational Building Corp. Rev., Hospital Financing (Lifespan Obligated Group), “A”, ASSD GTY, 7%, 2039		660,000		742,916
Royal Oak, MI, Hospital Finance Authority Rev. (William Beaumont Hospital), 8.25%, 2039		485,000		563,633
Salida, CO, Hospital District Rev., 5.25%, 2036		734,000		637,464
Skagit County, WA, Public Hospital District No. 001 Rev. (Skagit Valley Hospital), 5.75%, 2032		90,000		88,690
South Lake County, FL, Hospital District Rev. (South Lake Hospital), 6.375%, 2034		250,000		250,968
South Lake County, FL, Hospital District Rev. (South Lake Hospital), “A”, 6%, 2029		85,000		85,149
South Lake County, FL, Hospital District Rev. (South Lake Hospital), “A”, 6.25%, 2039		125,000		125,143
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.375%, 2015		350,000		350,228
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.5%, 2020		550,000		550,000
Southwestern, IL, Development Authority Rev. (Anderson Hospital), 5.125%, 2026		500,000		459,520
Sullivan County, TN, Health, Educational & Housing Facilities Board Hospital Rev. (Wellmont Health Systems Project), “C”, 5.25%, 2036		1,085,000		966,214
Sumner County, TN, Health, Educational & Housing Facilities Board Rev. (Sumner Regional Health Systems, Inc.), “A”, 5.5%, 2046 (d)		375,000		31,875
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.25%, 2032		230,000		196,944
Tyler, TX, Health Facilities Development Corp. (East Texas Medical Center), “A”, 5.375%, 2037		190,000		160,755

3

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Virginia Small Business Financing Authority, Hospital Rev. (Wellmont Health Project), “A”, 5.25%, 2037	$	470,000	$	416,575
Washington Health Care Facilities Authority Rev. (Multicare Health Systems), “B”, ASSD GTY, 6%, 2039		440,000		470,615
West Contra Costa, CA, Healthcare District, AMBAC, 5.5%, 2029		105,000		107,744
Wisconsin Health & Educational Facilities Authority Rev. (Aurora Health Care, Inc.), 6.4%, 2033		350,000		357,133
Wisconsin Health & Educational Facilities Authority Rev. (Fort Healthcare, Inc.), 6.1%, 2034		750,000		748,103
Wisconsin Health & Educational Facilities Authority Rev. (Meritor Hospital), “A”, 5.5%, 2031		725,000		734,150
Wisconsin Health & Educational Facilities Authority Rev. (Meritor Hospital), “A”, 6%, 2041		490,000		508,493
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), 5.75%, 2012 (c)		450,000		465,579
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), 5.25%, 2034		935,000		801,547
Wisconsin Health & Educational Facilities Authority Rev. (Wheaton Franciscan Services), “A”, 5.25%, 2025		390,000		369,311
			$	45,048,497
Healthcare Revenue - Long Term Care – 21.5%
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement Systems, Inc.), “A”, 5.9%, 2025	$	750,000	$	613,845
Abilene, TX, Health Facilities Development Corp., Retirement Facilities Rev. (Sears Methodist Retirement Systems, Inc.), “A”, 7%, 2033		200,000		170,586
Bucks County, PA, Industrial Development Authority Retirement Community Rev. (Ann’s Choice, Inc.), “A”, 6.125%, 2025		500,000		487,305
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2027		90,000		80,140
Bucks County, PA, Industrial Development Authority Rev. (Lutheran Community Telford Center), 5.75%, 2037		120,000		95,984
California Statewide Communities Development Authority Rev. (American Baptist Homes of the West), 6.25%, 2039		215,000		211,083
Capital Projects Finance Authority, FL, (Glenridge on Palmer Ranch), “A”, 8%, 2012 (c)		490,000		527,421
Chartiers Valley, PA, Industrial & Commercial Development Authority (Friendship Village), “A”, 5.75%, 2020		1,000,000		1,000,730
Chartiers Valley, PA, Industrial & Commercial Development Authority Rev. (Asbury Health Center), 6.375%, 2024		1,000,000		976,770
Colorado Health Facilities Authority Rev. (American Housing Foundation, Inc.), 8.5%, 2011 (c)		515,000		524,198
Colorado Health Facilities Authority Rev. (Christian Living Communities Project), “A”, 5.75%, 2037		475,000		424,527
Colorado Health Facilities Authority Rev. (Covenant Retirement Communities, Inc.), 5%, 2035		1,100,000		910,360
Columbus, GA, Housing Authority Rev. (Calvary Community, Inc.), 7%, 2019		370,000		338,269
Cumberland County, PA, Municipal Authority Rev. (Diakon Lutheran Social Ministries), 6.125%, 2029		695,000		707,420
Fulton County, GA, Residential Care Facilities (Canterbury Court), “A”, 6.125%, 2026		500,000		464,900
Hawaii Department of Budget & Finance, Special Purpose Rev. (15 Craigside Project), “A”, 9%, 2044		140,000		155,915
Houston, TX, Health Facilities Development Corp. (Buckingham Senior Living Community), “A”, 7%, 2014 (c)		500,000		582,375
Howard County, MD, Retirement Facilities Rev. (Vantage House Corp.), “A”, 5.25%, 2033		200,000		146,002

4

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Illinois Finance Authority Rev. (Evangelical Retirement Homes of Greater Chicago, Inc.), 7.25%, 2045	$	850,000	$	857,939
Illinois Finance Authority Rev. (Smith Village), “A”, 6.25%, 2035		1,000,000		864,250
Illinois Health Facilities Authority Rev. (Smith Crossing), “A”, 7%, 2032		525,000		494,629
Indiana Health Facilities Financing Authority Rev. (Hoosier Care, Inc.), “A”, 7.125%, 2034		975,000		882,356
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2018		415,000		407,858
Iowa Finance Authority, Health Care Facilities Rev. (Care Initiatives), “B”, 5.75%, 2028		1,475,000		1,264,326
James City County, VA, Economic Development (WindsorMeade Project), “A”, 5.5%, 2037		440,000		255,275
Kentucky Economic Development Finance Authority Health Facilities Rev. (AHF/Kentucky-Iowa, Inc.), 8%, 2029		353,000		354,751
La Verne, CA, COP (Brethren Hillcrest Homes), “B”, 6.625%, 2025		525,000		527,126
Massachusetts Development Finance Agency Rev. (Adventcare), “A”, 6.75%, 2037		695,000		641,541
Massachusetts Development Finance Agency Rev. (Alliance Health of Brockton, Inc.), “A”, 7.1%, 2032		1,020,000		901,313
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.5%, 2027		185,000		107,300
Massachusetts Development Finance Agency Rev. (Linden Ponds, Inc.), “A”, 5.75%, 2035		45,000		25,200
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 5.625%, 2015		155,000		155,028
Massachusetts Development Finance Agency Rev. (Loomis Communities, Inc.), “A”, 6.9%, 2032		125,000		126,414
Massachusetts Development Finance Agency Rev. (The Groves in Lincoln), “A”, 7.75%, 2039		80,000		81,707
Massachusetts Development Finance Agency Rev. (The Groves in Lincoln), “A”, 7.875%, 2044		115,000		117,274
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.125%, 2028		150,000		131,090
Montgomery County, PA, Industrial Development Authority Rev. (Whitemarsh Continuing Care), 6.25%, 2035		600,000		504,540
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.75%, 2025		400,000		376,204
New Jersey Economic Development Authority Rev. (Lions Gate), “A”, 5.875%, 2037		300,000		257,052
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2026		500,000		439,745
New Jersey Economic Development Authority Rev. (Seabrook Village, Inc.), 5.25%, 2036		500,000		414,940
Norfolk, VA, Redevelopment & Housing Authority Rev. (Fort Norfolk Retirement Community), “A”, 6.125%, 2035		195,000		174,069
Roseville, MN, Elder Care Facilities (Care Institute, Inc.), 7.75%, 2023		1,630,000		1,275,491
Shelby County, TN, Health, Educational & Housing Facilities Board Rev. (Germantown Village), “A”, 7.25%, 2034		300,000		281,151
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2027 (a)		280,000		140,868
South Carolina Jobs & Economic Development Authority Rev. (Woodlands at Furman), “A”, 6%, 2042 (a)		260,000		128,661
South Carolina Jobs & Economic Development Authority, Health Facilities Rev. (Wesley Commons), 5.3%, 2036		200,000		155,218
St. John’s County, FL, Industrial Development Authority Rev. (Glenmoor Project), “A”, 5.25%, 2026		500,000		405,235
St. John’s County, FL, Industrial Development Authority Rev. (Presbyterian Retirement), “A”, 6%, 2045		610,000		609,957
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Air Force Village), 6.125%, 2029		550,000		552,574

5

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Healthcare Revenue - Long Term Care – continued
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Air Force Village), 6.375%, 2044	$	415,000	$	414,668
Tarrant County, TX, Cultural Education Facilities Finance Corp. Retirement Facility (Stayton at Museum Way), 8.25%, 2044		770,000		783,567
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7%, 2030		130,000		133,514
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7.125%, 2040		195,000		196,995
Westmoreland County, PA, Industrial Development Authority Rev. (Redstone Retirement Community), “A”, 5.875%, 2032		600,000		522,648
Westmoreland County, PA, Industrial Development Retirement Authority Rev. (Redstone Retirement Community), “A”, 5.75%, 2026		1,250,000		1,130,938
			$	25,511,242
Healthcare Revenue - Other – 0.5%
Massachusetts Health & Educational Facilities Authority Rev. (Civic Investments, Inc.), “A”, 9%, 2012 (c)	$	550,000	$	608,482
Industrial Revenue - Airlines – 4.0%
Clayton County, GA, Development Authority Special Facilities Rev. (Delta Airlines, Inc.), “A”, 8.75%, 2029	$	200,000	$	230,324
Clayton County, GA, Development Authority Special Facilities Rev. (Delta Airlines, Inc.), “B”, 9%, 2035		150,000		160,853
Denver, CO, City & County Airport Rev. (United Airlines), 5.75%, 2032		355,000		313,923
Houston, TX, Airport Systems Rev., Special Facilities (Continental Airlines, Inc.), “E”, 6.75%, 2029		155,000		151,530
Houston, TX, Airport Systems Rev., Special Facilities (Continental Airlines, Inc.), “E”, 7%, 2029		200,000		200,020
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 6.25%, 2029		935,000		870,102
New Jersey Economic Development Authority, Special Facilities Rev. (Continental Airlines, Inc.), 9%, 2033		1,250,000		1,301,475
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.5%, 2016		600,000		611,028
New York, NY, City Industrial Development Agencies Rev. (American Airlines, Inc.), 7.75%, 2031		385,000		384,184
New York, NY, City Industrial Development Agency Special Facility Rev. (American Airlines, Inc.), “B”, 8.5%, 2028		500,000		510,350
			$	4,733,789
Industrial Revenue - Chemicals – 1.5%
Brazos River, TX, Harbor Navigation District (Dow Chemical Co.), “B-2”, 4.95%, 2033	$	400,000	$	374,704
Michigan Strategic Fund Ltd. Obligation Rev. (Dow Chemical Co.), 6.25%, 2014		655,000		724,489
Port of Bay, TX, City Authority (Hoechst Celanese Corp.), 6.5%, 2026		660,000		645,322
			$	1,744,515
Industrial Revenue - Environmental Services – 1.1%
California Pollution Control Financing Authority, Solid Waste Disposal Rev. (Republic Services, Inc.), “B”, 5.25%, 2023 (b)	$	135,000	$	145,770
California Pollution Control Financing Authority, Solid Waste Disposal Rev. (Waste Management, Inc.), “C”, 5.125%, 2023		655,000		665,487
Carbon County, UT, Solid Waste Disposal Rev. (Laidlaw Environmental), “A”, 7.45%, 2017		500,000		508,545
			$	1,319,802
Industrial Revenue - Other – 3.0%
Annawan, IL, Tax Increment Rev. (Patriot Renewable Fuels LLC), 5.625%, 2018	$	315,000	$	267,215

6

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Industrial Revenue - Other – continued
California Statewide Communities, Development Authority Facilities (Microgy Holdings Project), 9%, 2038 (d)	$	53,546	$	2,929
Gulf Coast, TX, Industrial Development Authority Rev. (CITGO Petroleum Corp.), 8%, 2028		375,000		372,589
Houston, TX, Industrial Development Corp. (United Parcel Service, Inc.), 6%, 2023		435,000		369,254
Indianapolis, IN, Airport Authority Rev., Special Facilities (FedEx Corp.), 5.1%, 2017		500,000		559,210
New Jersey Economic Development Authority Rev. (GMT Realty LLC), “B”, 6.875%, 2037		1,000,000		872,700
Virgin Islands Government Refinery Facilities Rev. (Hovensa Coker Project), 6.5%, 2021		250,000		246,238
Virgin Islands Public Finance Authority, Refinery Facilities Rev. (Hovensa Coker Project), 5.875%, 2022		400,000		369,916
Will-Kankakee, IL, Regional Development Authority Rev. (Flanders Corp.), 6.5%, 2017 (c)		500,000		508,085
			$	3,568,136
Industrial Revenue - Paper – 3.6%
Beauregard Parish, LA (Boise Cascade Corp.), 6.8%, 2027	$	1,000,000	$	918,680
Bedford County, VA, Industrial Development Authority Rev. (Nekooska Packaging Corp.), 5.6%, 2025		400,000		383,308
Brunswick & Glynn County, GA, Development Authority Rev. (Georgia-Pacific LLC), 5.55%, 2026		505,000		476,215
Courtland, AL, Industrial Development Board Solid Waste Disposal Rev. (Champion International Corp.), 6%, 2029		1,000,000		985,920
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 5%, 2026		980,000		886,087
Escambia County, FL, Environmental Improvement Rev. (International Paper Co.), “A”, 4.75%, 2030		290,000		243,681
Phenix City, AL, Industrial Development Board Environmental Improvement Rev., “A” (Mead Westvaco Coated Board Project), 6.35%, 2035		400,000		398,980
			$	4,292,871
Miscellaneous Revenue - Entertainment & Tourism – 1.3%
Agua Caliente Band of Cahuilla Indians, CA, Rev., 5.6%, 2013 (n)	$	335,000	$	334,913
Brooklyn, NY, Arena Local Development Corp. (Barclays Center Project), 6%, 2030		135,000		135,603
Brooklyn, NY, Arena Local Development Corp. (Barclays Center Project), 6.25%, 2040		85,000		86,206
Cow Creek Band of Umpqua Tribe of Indians, OR, “C”, 5.625%, 2026 (n)		650,000		522,971
Mashantucket Western Pequot Tribe, CT, Capital Appreciation, “B”, 0%, 2018 (a)(n)		1,100,000		250,360
New York Liberty Development Corp. Rev. (National Sports Museum), “A”, 6.125%, 2019 (d)		351,999		4
Seminole Tribe, FL, Special Obligation Rev., “A”, 5.25%, 2027 (n)		280,000		246,420
			$	1,576,477
Miscellaneous Revenue - Other – 3.1%
Austin, TX, Convention Center (Convention Enterprises, Inc.), “A”, SYNCORA, 5.25%, 2024	$	305,000	$	284,748
Capital Trust Agency, FL (Aero Syracuse LLC), 6.75%, 2032		350,000		301,994
Citizens Property Insurance Corp., FL, “A-1”, 5%, 2019		65,000		69,329
Citizens Property Insurance Corp., FL, “A-1”, 5%, 2020		305,000		322,214
Dallas, TX, Civic Center Convention Complex Rev., ASSD GTY, 5.25%, 2034		845,000		894,424
Massachusetts Port Authority Facilities Rev. (Conrac Project), “A”, 5.125%, 2041		40,000		40,474
New York Liberty Development Corp., Liberty Rev. (One Bryant Park LLC), 6.375%, 2049		955,000		999,245
Summit County, OH, Port Authority Building Rev. (Twinsburg Township), “D”, 5.125%, 2025		600,000		510,354

7

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Miscellaneous Revenue - Other – continued
V Lakes Utility District, MS, Water Systems Rev., 7%, 2037	$	300,000	$	263,862
			$	3,686,644
Multi-Family Housing Revenue – 4.9%
Broward County, FL, Housing Finance Authority Rev. (Chaves Lakes Apartments Ltd.), “A”, 7.5%, 2040	$	495,000	$	475,220
Capital Trust Agency, FL, Housing Rev. (Atlantic Housing Foundation), “B”, 4.5%, 2032 (q)		625,000		299,925
Charter Mac Equity Issuer Trust, FHLMC, 6%, 2019 (n)		1,000,000		1,029,880
District of Columbia Housing Finance Agency (Henson Ridge), “E”, FHA, 5.1%, 2037		655,000		641,160
Durham, NC, Durham Housing Authority Rev. (Magnolia Pointe Apartments), 5.65%, 2038 (b)		918,667		693,594
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “C”, 8%, 2032		275,000		276,705
El Paso County, TX, Housing Finance Corp. (American Housing Foundation), “D”, 10%, 2032		280,000		281,677
Mississippi Home Corp., Rev. (Kirkwood Apartments), 6.8%, 2037 (q)		605,000		336,071
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049 (z)		1,000,000		650,300
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016 (z)		455,481		435,727
Wilmington, DE, Multi-Family Housing Rev. (Electra Arms Senior Associates), 6.25%, 2028		780,000		667,306
			$	5,787,565
Parking – 0.3%
Boston, MA, Metropolitan Transit Parking Corp., Systemwide Parking Rev., 5.25%, 2036	$	300,000	$	312,837
Port Revenue – 1.5%
Maryland Economic Development Corp. Rev. (Port America Chesapeake Terminal Project), “B”, 5.75%, 2035	$	285,000	$	279,904
Port Authority NY & NJ, Cons Thirty Seventh, AGM, 5.125%, 2030		1,450,000		1,497,386
			$	1,777,290
Sales & Excise Tax Revenue – 6.3%
Bolingbrook, IL, Sales Tax Rev., 6.25%, 2024	$	500,000	$	310,565
Colorado Regional Transportation District, Private Activity Rev. (Denver Transportation Partners), 6%, 2034		630,000		627,638
Colorado Regional Transportation District, Private Activity Rev. (Denver Transportation Partners), 6%, 2041		300,000		297,516
Massachusetts Bay Transportation Authority, Sales Tax Rev., “A”, 5%, 2024 (f)		1,095,000		1,305,974
Massachusetts School Building Authority, Dedicated Sales Tax Rev., AMBAC, 4.75%, 2032		840,000		863,159
Metropolitan Pier & Exposition Authority, State Tax Rev., Capital Appreciation, NATL, 0%, 2015		3,000,000		2,701,050
Metropolitan Pier & Exposition Authority, State Tax Rev., Capital Appreciation, ETM, FGIC, 0%, 2014 (c)		1,010,000		991,153
Puerto Rico Sales Tax Financing Corp., Sales Tax Rev., “C”, 5.25%, 2041		35,000		34,841
Puerto Rico Sales Tax Financing Corp., Sales Tax Rev., Capital Appreciation, “A”, 0%, 2032		460,000		394,643
			$	7,526,539
Single Family Housing - Local – 1.2%
Minneapolis & St. Paul Housing Authority Rev. (City Living), “A-2”, GNMA, 5%, 2038	$	468,982	$	455,363
Pittsburgh, PA, Urban Redevelopment Authority Rev., “C”, GNMA, 4.8%, 2028		1,000,000		994,320
			$	1,449,683
Single Family Housing - State – 2.2%
California Housing Finance Agency Rev., “G”, 5.5%, 2042	$	330,000	$	330,155

8

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Single Family Housing - State – continued
Colorado Housing & Finance Authority, “A”, 5.5%, 2029	$	1,115,000	$	1,148,316
Iowa Finance Authority, Single Family Mortgage Rev., “E”, 5.4%, 2032		365,000		370,654
Kentucky Counties Single Family Mortgage Rev., “A”, NATL, 9%, 2016		5,000		5,000
North Dakota Housing Finance Agency Rev., “A”, 4.85%, 2021		165,000		166,653
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		210,000		218,675
Virginia Housing Development Authority, Commonwealth Mortgage, “A-5”, 4.4%, 2015		340,000		356,041
			$	2,595,494
Solid Waste Revenue – 0.1%
Pennsylvania Economic Development Financing Authority, Sewer Sludge Disposal Rev. (Philadelphia Biosolids Facility), 6.25%, 2032	$	75,000	$	78,149
State & Agency - Other – 0.5%
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.25%, 2024	$	100,000	$	97,901
Commonwealth of Puerto Rico (Mepsi Campus), “A”, 6.5%, 2037		500,000		470,195
			$	568,096
State & Local Agencies – 5.0%
Dorchester County, SC, School District No. 2, Growth Remedy Opportunity Tax Hike, 5.25%, 2029	$	500,000	$	511,595
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Enhanced, “A”, FGIC, 5%, 2035		110,000		101,671
Guam Government Department of Education (John F. Kennedy High School), “A”, COP, 6.875%, 2040		295,000		295,655
Laurens County, SC, School District No. 55, Installment Purchase Rev., 5.25%, 2030		700,000		712,425
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024 (c)		45,000		45,234
Michigan Building Authority Rev., Facilities Program, “I”, 5%, 2024		955,000		960,014
New York Metropolitan Transportation Authority, “A”, 5.125%, 2029		800,000		811,736
Newberry, SC, Investing in Children’s Education (Newberry County School District Program), 5%, 2030		400,000		405,144
Philadelphia, PA, Municipal Authority Rev., 6.5%, 2034		135,000		139,714
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026 (c)		80,000		105,598
Puerto Rico Public Finance Corp., “E”, ETM, 6%, 2026		820,000		1,093,896
Wisconsin General Fund Annual Appropriation Rev., “A”, 5.75%, 2033		660,000		727,683
			$	5,910,365
Student Loan Revenue – 0.4%
Massachusetts Educational Financing Authority, Education Loan Rev., “H”, ASSD GTY, 6.35%, 2030	$	425,000	$	442,417
Massachusetts Educational Financing Authority, Education Loan Rev., “I-A”, 5.5%, 2022		25,000		27,096
			$	469,513
Tax - Other – 1.5%
Dallas County, TX, Flood Control District, 7.25%, 2032	$	750,000	$	767,963
Hudson Yards, NY, Infrastructure Corp. Rev., “A”, 5%, 2047		360,000		347,260
New York, NY, City Transitional Finance Authority Building Aid Rev., “S-3”, 5.25%, 2039		440,000		461,578
Virgin Islands Public Finance Authority Rev. (Diageo Project), “A”, 6.75%, 2037		205,000		216,722
			$	1,793,523
Tax Assessment – 8.1%
Anne Arundel County, MD, Special Obligation (National Business Park-North Project), 6.1%, 2040	$	140,000	$	133,081
Atlanta, GA, Tax Allocation (Eastside Project), “B”, 5.4%, 2020		500,000		510,845
Capital Region Community Development District, FL, Capital Improvement Rev., “A”, 7%, 2039		230,000		190,433
Celebration Community Development District, FL, “A”, 6.4%, 2034		675,000		678,186

9

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tax Assessment – continued
Channing Park Community Development District, FL, 5.3%, 2038	$	300,000	$	239,364
Chicago, IL, Tax Increment Allocation (Pilsen Redevelopment), “B”, 6.75%, 2022		310,000		311,321
Du Page County, IL, Special Service Area No. 31 Special Tax (Monarch Landing Project), 5.625%, 2036		250,000		196,870
Heritage Harbour North Community Development District, FL, Capital Improvement Rev., 6.375%, 2038		315,000		267,057
Homestead, FL, Community Development District, Special Assessment, “A”, 6%, 2037		365,000		226,293
Homestead, FL, Community Development District, Special Assessment, “B”, 5.9%, 2013		150,000		89,172
Huntington Beach, CA, Community Facilities District, Special Tax (Grand Coast Resort), “2000-1”, 6.45%, 2031		500,000		501,190
Lincolnshire, IL, Special Service Area No. 1 (Sedgebrook Project), 6.25%, 2034		250,000		222,973
Main Street Community Development District, FL, “A”, 6.8%, 2038		280,000		238,272
Northwest Metropolitan District No. 3, CO, 6.25%, 2035		500,000		399,295
Oakmont Grove Community Development District, FL, “A”, 5.4%, 2038 (d)		300,000		111,000
Ohio County, WV, Commission Tax Increment Rev. (Fort Henry Centre), “A”, 5.85%, 2034		125,000		125,651
Orlando, FL, Special Assessment Rev. (Conroy Road Interchange Project), “A”, 5.8%, 2026		290,000		282,170
Plano, IL, Special Service Area No. 4 (Lakewood Springs Project Unit 5-B), 6%, 2035		1,460,000		1,280,727
San Diego, CA, Redevelopment Agency, Tax Allocation, Capital Appreciation, AGM, 0%, 2018		1,015,000		749,912
Sarasota National Community Development District, FL, Special Assessment Rev., 5.3%, 2039 (d)		800,000		239,000
Sweetwater Creek Community Development District, FL, Capital Improvement Rev., 5.5%, 2038		190,000		83,600
Tolomato Community Development District, FL, Special Assessment, 6.65%, 2040		585,000		378,594
Tuscany Reserve Community Development District, FL, Special Assessment, “B”, 5.25%, 2016		185,000		160,595
Volo Village, IL, Special Service Area No. 3, Special Tax (Symphony Meadows Project), “1”, 6%, 2036		483,000		363,796
West Villages Improvement District, FL, Special Assessment Rev. (Unit of Development No. 3), 5.5%, 2037		470,000		208,121
Westridge, FL, Community Development District, Capital Improvement Rev., 5.8%, 2037 (d)		960,000		364,800
Wyandotte County-Kansas City, KS, Unified Government Transportation Development District (Legends Village West Project), 4.875%, 2028		580,000		428,434
Yorba Linda, CA, Redevelopment Agency, Tax Allocation Rev., Capital Appreciation, “A”, NATL, 0%, 2024		1,325,000		586,167
			$	9,566,919
Tobacco – 8.4%
Buckeye, OH, Tobacco Settlement Financing Authority, “A-2”, 5.125%, 2024	$	3,270,000	$	2,546,938
Buckeye, OH, Tobacco Settlement Financing Authority, “A-2”, 5.875%, 2030		245,000		184,649
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 6.25%, 2013 (c)		970,000		1,048,648
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., “A-1”, 5.75%, 2047		525,000		370,235
Golden State, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, “A-1”, 5%, 2033		440,000		304,594
Illinois Railsplitter Tobacco Settlement Authority, 6%, 2028		1,365,000		1,396,163
Inland Empire, CA, Tobacco Securitization Corp., Tobacco Settlement Rev., Asset Backed, Capital Appreciation, “C-1”, 0%, 2036		1,815,000		162,787
New Jersey Tobacco Settlement Financing Corp., “1-A”, 5%, 2041		3,355,000		2,215,843
Rhode Island Tobacco Settlement Authority, 6%, 2023		1,260,000		1,270,975

10

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Tobacco – continued
Washington Tobacco Settlement Authority Rev., 6.625%, 2032	$	500,000	$	503,385
			$	10,004,217
Toll Roads – 4.1%
E-470 Public Highway Authority, CO, Capital Appreciation, “B”, NATL, 0%, 2018	$	1,500,000	$	1,026,765
Mid-Bay Bridge Authority, FL, Springing Lien Rev., “A”, 7.25%, 2040		215,000		218,201
North Texas Tollway Authority Rev., 6%, 2038		765,000		812,002
San Joaquin Hills, CA, Transportation Corridor Agency, Toll Road Rev., Capital Appreciation, “A”, NATL, 0%, 2015		3,000,000		2,448,600
Texas Private Activity Bond, Surface Transportation Corp., 7%, 2040		400,000		415,384
			$	4,920,952
Universities - Colleges – 9.1%
Brevard County, FL, Industrial Development Rev. (TUFF Florida Tech LLC Project), 6.75%, 2039	$	540,000	$	559,073
California Educational Facilities Authority Rev. (University of Southern California), “A”, 5.25%, 2038		1,270,000		1,363,650
California Municipal Finance Authority Rev. (Biola University), 5.8%, 2028		100,000		102,350
Florida State University Board of Governors, System Improvement Rev., 6.25%, 2030		1,000,000		1,154,290
Grand Valley, MI, State University Rev., 5.5%, 2027		135,000		145,264
Grand Valley, MI, State University Rev., 5.625%, 2029		65,000		69,782
Harris County, TX, Cultural Education Facilities Rev. (Baylor College of Medicine), “D”, 5.625%, 2032		540,000		518,967
Illinois Finance Authority Rev. (Illinois Institute of Technology), “A”, 5%, 2036		110,000		79,239
Illinois Finance Authority Rev. (Roosevelt University Project), 6.25%, 2029		670,000		698,375
Illinois Finance Authority Rev. (Roosevelt University Project), 6.5%, 2039		155,000		162,006
Massachusetts Development Finance Agency Rev. (The Broad Institute, Inc.), “A”, 5.25%, 2037		580,000		590,457
Massachusetts Health & Educational Facilities Authority Rev. (Simmons College), “I”, 8%, 2029		255,000		287,637
Massachusetts Health & Educational Facilities Authority Rev. (Suffolk University), “A”, 6.25%, 2030		725,000		772,857
Massachusetts Health & Educational Facilities Authority Rev. (Suffolk University), “A”, 5.75%, 2039		455,000		443,862
Ohio Higher Education Facilities Rev. (Ashland University Project), 6.25%, 2024		660,000		674,540
Savannah, GA, Economic Development Authority Rev. (AASU Student Union LLC), ASSD GTY, 5.125%, 2039		335,000		347,482
University of Illinois Rev. (Auxiliary Facilities Systems), “A”, 5.125%, 2029		1,880,000		1,948,507
University of Southern Indiana Rev. (Student Fee), “J”, ASSD GTY, 5.75%, 2028		300,000		331,539
University of Southern Mississippi Educational Building Corp. Rev. (Campus Facilities Project), 5.25%, 2032		220,000		237,081
University of Southern Mississippi Educational Building Corp. Rev. (Campus Facilities Project), 5.375%, 2036		80,000		86,265
Washington Higher Education Facilities Authority Rev. (Whitworth University), 5.875%, 2034		280,000		283,301
			$	10,856,524
Universities - Dormitories – 1.9%
Buffalo & Erie County, NY, Industrial Land Development Corp. Rev. (Buffalo State College), “A”, 5.375%, 2041	$	200,000	$	205,336
California Statewide Communities Development Authority Rev. (Lancer Educational Student Housing Project), 5.625%, 2033		735,000		630,917
Illinois Finance Authority Student Housing Rev. (Illinois State University), 6.75%, 2031		240,000		249,934
Illinois Finance Authority Student Housing Rev. (Northern Illinois University Project), 6.625%, 2031		480,000		488,966
Mississippi State University, Educational Building Corp., 5%, 2036		440,000		455,624

11

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Universities - Dormitories – continued
Pennsylvania Higher Education Facilities Authority Rev. (Edinboro University Foundation), 5.8%, 2030	$	80,000	$	80,266
Pennsylvania Higher Education Facilities Authority Rev. (Edinboro University Foundation), 6%, 2043		110,000		108,301
			$	2,219,344
Universities - Secondary Schools – 0.8%
Clifton, TX, Higher Education Finance Corp. Rev. (Uplift Education), “A”, 6.125%, 2040	$	215,000	$	205,562
Clifton, TX, Higher Education Finance Corp. Rev. (Uplift Education), “A”, 6.25%, 2045		135,000		131,455
La Vernia, TX, Higher Education Finance Corp. Rev. (KIPP, Inc.), “A”, 6.25%, 2039		195,000		200,013
Lee County, FL, Industrial Development Authority Rev. (Lee Charter Foundation), “A”, 5.375%, 2037		535,000		415,064
Philadelphia, PA, Authority for Industrial Development Rev. (MaST Charter School), 6%, 2035		50,000		50,789
			$	1,002,883
Utilities - Cogeneration – 0.7%
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Central Facilities (Cogeneration Facilities - AES Puerto Rico Project), 6.625%, 2026	$	320,000	$	320,330
Suffolk County, NY, Industrial Development Agency Rev. (Nissequoque Cogeneration Partners Facilities), 5.5%, 2023		550,000		526,719
			$	847,049
Utilities - Investor Owned – 5.5%
Brazos River Authority, TX, Pollution Control Rev. (TXU Electric Co. LLC), “C”, 6.75%, 2038	$	555,000	$	199,328
Bryant, IL, Pollution Control Rev. (Central Illinois Light Co.), 5.9%, 2023		975,000		977,545
Chula Vista, CA, Industrial Development Rev. (San Diego Gas), 5.875%, 2034		245,000		267,285
Farmington, NM, Pollution Control Rev. (Public Service New Mexico), “D”, 5.9%, 2040		500,000		499,260
Maricopa County, AZ, Pollution Control Corp., Pollution Control Rev. (Arizona Public Service Co.), “D”, 6%, 2029 (b)		475,000		522,153
Massachusetts Development Finance Agency, Solid Waste Disposal Rev. (Dominion Energy Brayton), 5.75%, 2042 (b)		85,000		92,786
Matagorda County, TX, Pollution Control Rev. (Central Power & Light Co.), “A”, 6.3%, 2029		275,000		295,163
Mississippi Business Finance Corp., Pollution Control Rev. (Systems Energy Resources Project), 5.875%, 2022		1,500,000		1,500,000
New Hampshire Business Finance Authority, Pollution Control Rev. (Public Service of New Hampshire), “B”, NATL, 4.75%, 2021		250,000		256,965
Owen County, KY, Waterworks System Rev. (American Water Co. Project), “A”, 6.25%, 2039		205,000		213,122
Pennsylvania Economic Development Financing Authority (Allegheny Energy Supply Co. LLC), 7%, 2039		600,000		651,168
Pima County, AZ, Industrial Development Authority Rev. (Tucson Electric Power Co.), 5.75%, 2029		1,015,000		1,029,707
			$	6,504,482
Utilities - Municipal Owned – 0.1%
Harris County, TX, Cultural Education Facilities Financial Corp., Thermal Utilities Rev. (Teco Project), “A”, 5.25%, 2035	$	140,000	$	147,707
Utilities - Other – 3.7%
California M-S-R Energy Authority Gas Rev., “A”, 7%, 2034	$	155,000	$	178,301
California M-S-R Energy Authority Gas Rev., “A”, 6.5%, 2039		335,000		365,338
Georgia Main Street Natural Gas, Inc., Gas Project Rev., “A”, 5.5%, 2028		335,000		322,809
Georgia Main Street Natural Gas, Inc., Gas Project Rev., “B”, 5%, 2019		325,000		329,677
Indiana Bond Bank Special Program, Gas Rev., “A”, 5.25%, 2018		230,000		249,550
Public Authority for Colorado Energy Natural Gas Purchase Rev., 6.5%, 2038		25,000		26,698

12

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

Issuer	Shares/Par		Value ($)
Municipal Bonds – continued
Utilities - Other – continued
Salt Verde Financial Corp., AZ, Senior Gas Rev., 5%, 2037	$	705,000	$	609,035
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2021		1,710,000		1,703,417
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2022		270,000		267,114
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 2026		165,000		161,319
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2025		240,000		234,718
			$	4,447,976
Water & Sewer Utility Revenue – 6.8%
Atlanta, GA, Water & Wastewater Rev., “A”, 6%, 2022	$	370,000	$	435,960
Birmingham, AL, Waterworks Board Water Rev., “A”, ASSD GTY, 5.125%, 2034		595,000		620,573
Commonwealth of Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2038		655,000		662,225
Commonwealth of Puerto Rico Aqueduct & Sewer Authority Rev., “A”, 6%, 2044		135,000		136,338
Detroit, MI, Sewer Disposal System Rev., “B”, AGM, 7.5%, 2033		515,000		606,922
Houston, TX, Utility System Rev., “D”, 5%, 2036		435,000		456,589
King County, WA, Sewer Rev., 5%, 2040		1,395,000		1,461,793
Massachusetts Water Resources Authority, “B”, 5%, 2041		275,000		294,737
New York Environmental Facilities Corp., Clean Drinking Water Revolving Funds, 5%, 2024		215,000		248,820
New York Environmental Facilities Corp., Clean Drinking Water Revolving Funds, 5%, 2041		685,000		731,354
New York Environmental Facilities, “C”, 5%, 2041		945,000		1,014,750
New York, NY, Municipal Water Finance Authority, Water & Sewer Systems Rev. “DD”, 4.75%, 2035		790,000		807,151
Surprise, AZ, Municipal Property Corp., 4.9%, 2032		700,000		626,325
			$	8,103,537
Total Municipal Bonds			$	186,975,133
Money Market Funds (v) – 3.4%
MFS Institutional Money Market Portfolio, 0.08%, at Net Asset Value		4,023,391	$	4,023,391
Total Investments			$	190,998,524
Other Assets, Less Liabilities – 2.3%				2,691,417
Preferred shares (Issued by the Fund) – (63.2)%				(75,000,000	)
Net assets applicable to common shares – 100.0%			$	118,689,941

(a) Non-income producing security.

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

(c) Refunded bond.

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

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

(n) Securities exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be sold in the ordinary course of business in transactions exempt from registration, normally to qualified institutional buyers. At period end, the aggregate value of these securities was $2,384,544, representing 2.0% of net assets applicable to common shares.

(q) Interest received was less than stated coupon rate and a scheduled principal payment was missed.

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

13

MFS High Yield Municipal Trust

PORTFOLIO OF INVESTMENTS (unaudited) 8/31/11 - continued

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

Restricted Securities	Acquisition Date	Cost		Value
MuniMae TE Bond Subsidiary LLC, 5.8%, 2049	10/14/04	$	1,000,000	$	650,300
Resolution Trust Corp., Pass-Through Certificates, “1993”, 8.5%, 2016	10/17/01 - 1/14/02		455,481		435,727
Total Restricted Securities				$	1,086,027
% of Net Assets Applicable to Common Shares					0.9	%

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

COP	Certificate of Participation
ETM	Escrowed to Maturity
LOC	Letter of Credit
Insurers
AGM	Assured Guaranty Municipal
AMBAC	AMBAC Indemnity Corp.
ASSD GTY	Assured Guaranty Insurance Co.
FGIC	Financial Guaranty Insurance Co.
FHA	Federal Housing Administration
FHLMC	Federal Home Loan Mortgage Corp.
GNMA	Government National Mortgage Assn.
NATL	National Public Finance Guarantee Corp.
PSF	Permanent School Fund
SYNCORA	Syncora Guarantee Inc.

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

14

MFS High Yield Municipal Trust

Supplemental Information (Unaudited) 8/31/11

(1) Investment Valuations

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

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

Various inputs are used in determining the value of the fund’s assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes unobservable inputs, which may include the adviser’s own assumptions in determining the fair value of investments. Other financial instruments are derivative instruments not reflected in total investments, such as futures. The following is a summary of the levels used as of August 31, 2011 in valuing the fund’s assets or liabilities:

Investments at Value	Level 1		Level 2		Level 3		Total
Municipal Bonds	$	—	$	186,975,133	$	—	$	186,975,133
Mutual Funds		4,023,391		—		—		4,023,391
Total Investments	$	4,023,391	$	186,975,133	$	—	$	190,998,524
Other Financial Instruments
Futures	$	30,917	$	—	$	—	$	30,917

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

(2) Portfolio Securities

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

Aggregate cost	$	192,389,358
Gross unrealized appreciation	$	9,333,250
Gross unrealized depreciation		(10,724,084	)
Net unrealized appreciation (depreciation)	$	(1,390,834	)

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

15

MFS High Yield Municipal Trust

Supplemental Information (Unaudited) 8/31/11 - continued

(3) Derivative Contracts at 8/31/11

Futures Contracts Outstanding at 8/31/11

Description	Currency	Contracts	Value		Expiration Date		Unrealized Appreciation (Depreciation)
Asset Derivatives
Interest Rate Futures
U.S. Treasury Note 10 yr (Short)	USD	188	$	24,257,875		December-2011	$	2,279
U.S. Treasury Bond 30 yr (Short)	USD	32		4,353,000		December-2011		28,638
							$	30,917

At August 31, 2011, the fund had sufficient cash and/or other liquid securities to cover any commitments under these derivative contracts.

(4) Transactions in Underlying Affiliated Funds-Affiliated Issuers

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

Underlying Affiliated Funds	Beginning Shares/Par Amount		Acquisitions Shares/Par Amount		Dispositions Shares/Par Amount			Ending Shares/Par Amount
MFS Institutional Money Market Portfolio		—		30,308,806		(26,285,415	)		4,023,391
Underlying Affiliated Funds	Realized Gain (Loss)		Capital Gain Distributions		Dividend Income			Ending Value
MFS Institutional Money Market Portfolio	$	—	$	—	$	7,216		$	4,023,391

16

ITEM 2. CONTROLS AND PROCEDURES.

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

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

ITEM 3. EXHIBITS.

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

Notice

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

SIGNATURES

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

Registrant: MFS HIGH YIELD MUNICIPAL TRUST

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

Date: October 17, 2011

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

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

Date: October 17, 2011

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

Date: October 17, 2011

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