Quarterly Report

June 30, 2020

MFS^® Maryland
Municipal Bond Fund

Portfolio of Investments

6/30/20 (unaudited)

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 – 98.2%
Airport Revenue – 0.7%
Metropolitan Washington, DC, Airport Authority Rev., “A”, 5%, 10/01/2039	$	750,000	$758,798
General Obligations - General Purpose – 13.3%
Anne Arundel County, MD, Consolidated Water & Sewer, 5%, 10/01/2040	$	400,000	$520,780
Baltimore County, MD, Metropolitan District (80th Issue), 5%, 3/01/2033		1,250,000	1,595,800
Baltimore County, MD, Public Improvement, 5%, 2/01/2028		2,000,000	2,136,000
Baltimore County, MD, Public Improvement, 4%, 3/01/2037		1,750,000	2,096,692
Bridgeview, IL, Stadium and Redevelopment Projects, AAC, 5.14%, 12/01/2036		225,000	215,512
Commonwealth of Puerto Rico, General Obligation, “A”, 8%, 7/01/2035 (a)(d)		1,120,000	672,000
Commonwealth of Puerto Rico, Public Improvement, “A-4”, AGM, 5%, 7/01/2031		65,000	65,276
Harford County, MD, Consolidated Public Improvement, “A”, 5%, 10/01/2030		1,025,000	1,393,282
Howard County, MD, Metropolitan District Project, “C”, 4%, 2/15/2048		1,500,000	1,724,625
Montgomery County, MD, Consolidated Public Improvement, “A”, 5%, 11/01/2026 (Prerefunded 11/01/2024)		500,000	599,835
Prince George's County, MD, Consolidated Public Improvement, “A”, 5%, 9/15/2030 (Prerefunded 9/15/2021)		1,500,000	1,585,320
Prince George's County, MD, Consolidated Public Improvement, “A”, 5%, 7/15/2033		1,000,000	1,293,110
Puerto Rico Public Buildings Authority Rev., Guaranteed, “D”, AAC, 5.45%, 7/01/2030		115,000	115,090
State of Illinois, 5.5%, 5/01/2039		160,000	180,034
State of Illinois, “A”, 4%, 12/01/2033		40,000	39,528
			$14,232,884
General Obligations - Schools – 0.0%
Berks County, PA, Reading School District, AGM, 5%, 3/01/2036	$	20,000	$24,057
Healthcare Revenue - Hospitals – 18.3%
Chattanooga, TN, Health, Educational & Housing Facility Board Rev. (CommonSpirit Health), “A-1”, 4%, 8/01/2044	$	5,000	$5,388
Chattanooga, TN, Health, Educational & Housing Facility Board Rev. (CommonSpirit Health), “A-2”, 5%, 8/01/2044		10,000	11,739
Chattanooga, TN, Health, Educational & Housing Facility Board Rev. (CommonSpirit Health), “A-2”, 5%, 8/01/2049		5,000	5,830
Colorado Health Facilities Authority Rev. (CommonSpirit Health), “A-2”, 4%, 8/01/2044		55,000	59,269
Doylestown, PA, Hospital Rev., “A”, 4%, 7/01/2045		15,000	15,718
Escambia County, FL, Health Facilities Authority Rev. (Baptist Hospital, Inc.), “A”, 6%, 8/15/2036		590,000	592,714
Hamilton County, OH, Hospital Facilities Improvement Refunding Rev. (Trihealth, Inc. Obligated Group Project), “A”, 5%, 8/15/2033		45,000	57,117
Hamilton County, OH, Hospital Facilities Improvement Refunding Rev. (Trihealth, Inc. Obligated Group Project), “A”, 5%, 8/15/2034		85,000	107,623
Hamilton County, OH, Hospital Facilities Improvement Refunding Rev. (Trihealth, Inc. Obligated Group Project), “A”, 5%, 8/15/2035		60,000	75,604
Knox County, IN, Health Educational & Housing Facility Rev. (University Health System, Inc.), “A”, 5%, 9/01/2030		490,000	589,837
Maryland Health & Higher Educational Facilities Authority Rev. (Carroll Hospital), “A”, 5%, 7/01/2037		1,000,000	1,089,530
Maryland Health & Higher Educational Facilities Authority Rev. (Doctors Community Hospital), “A”, 5%, 7/01/2034		750,000	849,420
Maryland Health & Higher Educational Facilities Authority Rev. (Frederick Health System), 4%, 7/01/2045		1,000,000	1,098,630
Maryland Health & Higher Educational Facilities Authority Rev. (Johns Hopkins Health System), “A”, 5%, 5/15/2026		250,000	260,327
Maryland Health & Higher Educational Facilities Authority Rev. (LifeBridge Health), 5%, 7/01/2028		750,000	876,022
Maryland Health & Higher Educational Facilities Authority Rev. (LifeBridge Health), 5%, 7/01/2033		400,000	469,064
Maryland Health & Higher Educational Facilities Authority Rev. (LifeBridge Health), 4%, 7/01/2042		1,000,000	1,098,340
Maryland Health & Higher Educational Facilities Authority Rev. (Medlantic/Helix Parent, Inc.), “A”, AGM, 5.25%, 8/15/2038		1,000,000	1,324,330
Maryland Health & Higher Educational Facilities Authority Rev. (MedStar Health), “A”, 5%, 8/15/2041		505,000	547,612
Maryland Health & Higher Educational Facilities Authority Rev. (MedStar Health), “A”, 5%, 5/15/2042		750,000	862,155
Maryland Health & Higher Educational Facilities Authority Rev. (Mercy Medical Center), “A”, 5%, 7/01/2032		600,000	687,930
Maryland Health & Higher Educational Facilities Authority Rev. (Meritus Medical Center), 5%, 7/01/2027		500,000	583,690
Maryland Health & Higher Educational Facilities Authority Rev. (Peninsula Regional Health System), “A”, 5%, 7/01/2035		500,000	621,865
Maryland Health & Higher Educational Facilities Authority Rev. (Trinity Health Credit Group), “MD”, 5%, 12/01/2046		1,000,000	1,181,080
Maryland Health & Higher Educational Facilities Authority Rev. (University of Maryland Medical System), “B”, 5%, 7/01/2034		1,000,000	1,193,280
Maryland Health & Higher Educational Facilities Authority Rev. (University of Maryland Medical System), “D”, 4%, 7/01/2048		1,250,000	1,346,637
Maryland Health & Higher Educational Facilities Authority Rev. (Western Maryland Health System), 5.25%, 7/01/2034		1,000,000	1,187,750
Maryland Industrial Development Authority, Economic Development Rev., RIBS, AGM, 11.271%, 8/26/2022 (p)		400,000	450,672
Massachusetts Development Finance Agency Rev., “J-2”, 5%, 7/01/2048		480,000	558,274

1

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
Montgomery County, MD, Rev. (Trinity Health Corp.), 5%, 12/01/2040	$	1,000,000	$1,064,640
Spartanburg County, SC, Regional Health Services District Hospital Rev., “A”, 4%, 4/15/2043		635,000	686,435
			$19,558,522
Healthcare Revenue - Long Term Care – 4.5%
Baltimore County, MD, Rev. (Oak Crest Village, Inc.), 4%, 1/01/2045	$	1,000,000	$1,047,520
Baltimore County, MD, Rev. (Riderwood Village, Inc.), 4%, 1/01/2038		450,000	492,295
Howard County, MD, Retirement Community Rev. (Vantage House Facility), 5%, 4/01/2036		500,000	494,595
Maryland Health & Higher Educational Facilities Authority Rev. (Charlestown Community Project), 6.25%, 1/01/2041 (Prerefunded 1/01/2021)		750,000	771,315
Maryland Health & Higher Educational Facilities Authority Rev. (Charlestown Community Project), “A”, 5%, 1/01/2045		500,000	548,185
Rockville, MD, Mayor & Council Economic Development Rev. (Ingleside at King Farm Project), “B”, 5%, 11/01/2042		350,000	324,237
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7%, 11/01/2030 (Prerefunded 11/01/2020)		45,000	45,972
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), 7.125%, 11/01/2040 (Prerefunded 11/01/2020)		85,000	86,871
Travis County, TX, Health Facilities Development Corp. Rev. (Westminster Manor Health), Unrefunded Balance, 7%, 11/01/2030		5,000	5,065
Washington County, MD, County Commissioners Rev. (Diakon Lutheran Social Ministries Project), “B”, 5%, 1/01/2032		575,000	644,839
Westminster, MD, Refunding Rev. (Carroll Lutheran Village, Inc.), 5.125%, 7/01/2040		400,000	400,072
			$4,860,966
Healthcare Revenue - Other – 0.5%
Maryland Economic Development Corp., Economic Development Rev. (Lutheran World Relief Refugee), 5.25%, 4/01/2029	$	520,000	$520,738
Industrial Revenue - Other – 0.5%
Port Beaumont, TX, Navigation District Facility Rev. (Jefferson Gulf Coast Energy Project), “A”, 4%, 1/01/2050 (n)	$	200,000	$190,668
Tuscaloosa County, AL, Industrial Development Authority, Gulf Opportunity Zone (Hunt Refining Project), “A”, 5.25%, 5/01/2044		295,000	321,960
			$512,628
Industrial Revenue - Paper – 0.1%
Valparaiso, IN, Exempt Facilities Rev. (Pratt Paper LLC Project), 7%, 1/01/2044	$	100,000	$106,905
Miscellaneous Revenue - Other – 3.1%
Indiana Finance Authority Rev. (Ohio River Bridges East End Crossing Project), “A”, 5%, 7/01/2040	$	105,000	$111,810
Maryland Economic Development Corp., Air Cargo Obligated Group Rev. (AFCO Airport Real Estate Group), 5%, 7/01/2028		90,000	108,185
Maryland Economic Development Corp., Air Cargo Obligated Group Rev. (AFCO Airport Real Estate Group), 5%, 7/01/2029		210,000	255,969
Maryland Economic Development Corp., Air Cargo Obligated Group Rev. (AFCO Airport Real Estate Group), 4%, 7/01/2039		1,100,000	1,195,392
Maryland Economic Development Corp., Air Cargo Obligated Group Rev. (AFCO Airport Real Estate Group), 4%, 7/01/2044		600,000	638,514
Montgomery County, MD, Transportation Fund Lease Authority Rev., “A”, 5%, 11/01/2036		415,000	476,437
New York, NY, Industrial Development Agency, Airport Facilities Rev. (Transportation Infrastructure Properties LLC), 5%, 7/01/2028		450,000	475,596
			$3,261,903
Multi-Family Housing Revenue – 9.4%
Howard County, MD, Housing Commission Rev. (Columbia Commons Apartments), “A”, 5%, 6/01/2044	$	500,000	$542,985
Howard County, MD, Housing Commission Rev. (Woodfield Oxford Square Apartments), 5%, 12/01/2037		750,000	890,182
Maryland Community Development Administration, Department of Housing & Community Development Housing Rev., “A”, FHA, 4%, 7/01/2048		500,000	546,065
Maryland Community Development Administration, Department of Housing & Community Development Housing Rev., “B”, 3.65%, 7/01/2049		505,000	542,865
Maryland Community Development Administration, Department of Housing & Community Development Housing Rev., “D”, 3.35%, 7/01/2049		1,765,000	1,881,490
Maryland Community Development Administration, Department of Housing & Community Development Residential Rev., “C”, 5%, 3/01/2031		1,150,000	1,467,377
Maryland Community Development Administration, Department of Housing & Community Development Residential Rev., “C”, 3%, 9/01/2039		1,000,000	1,051,970
Montgomery County, MD, Housing Opportunities Commission, Multi-Family Housing Development Rev., “A-1”, FHA, 3.05%, 7/01/2044		1,000,000	1,055,670

2

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Multi-Family Housing Revenue – continued
Montgomery County, MD, Housing Opportunities Commission, Multi-Family Housing Development Rev., “C”, 5.125%, 7/01/2037	$	1,000,000	$1,008,420
Montgomery County, MD, Housing Opportunities Commission, Multi-Family Housing Development, “C”, 3.1%, 7/01/2036		1,065,000	1,095,619
			$10,082,643
Parking – 1.3%
Maryland Health & Higher Educational Facilities Authority Rev. (Johns Hopkins Medical Institutions), AAC, 5%, 7/01/2034	$	1,385,000	$1,398,033
Port Revenue – 1.4%
Maryland Economic Development Corp. Rev. (Terminal Project), “A”, 5%, 6/01/2044	$	500,000	$534,020
Maryland Economic Development Corp. Rev. (Terminal Project), “A”, 5%, 6/01/2049		250,000	265,235
Maryland Economic Development Corp. Rev. (Transportation Facilities Project), “A”, 5%, 6/01/2031		650,000	722,592
			$1,521,847
Sales & Excise Tax Revenue – 3.9%
Colorado Regional Transportation District, Private Activity Rev. (Denver Transportation Partners), 6%, 1/15/2041	$	435,000	$435,731
Guam Government Business Privilege Tax Rev., “A”, 5.25%, 1/01/2036		260,000	267,267
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2026		40,000	46,317
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2027		90,000	106,017
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2028		80,000	95,993
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2029		15,000	18,290
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2030		40,000	49,305
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2036		25,000	29,741
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 5%, 1/01/2037		50,000	60,086
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 4%, 1/01/2038		40,000	42,766
Illinois Sales Tax Securitization Corp., Second Lien, “A”, 4%, 1/01/2040		25,000	27,150
Metropolitan Pier & Exposition Authority Rev. (McCormick Place Expansion Project), “A”, AGM, 4%, 6/15/2050		600,000	621,252
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-1”, 4.55%, 7/01/2040		21,000	21,410
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-1”, 5%, 7/01/2058		797,000	833,303
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.329%, 7/01/2040		241,000	242,116
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.329%, 7/01/2040		75,000	75,347
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.784%, 7/01/2058		46,000	47,428
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2024		3,000	2,703
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2027		36,000	29,630
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2029		6,000	4,580
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2031		338,000	237,969
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2033		332,000	214,615
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2046		2,229,000	628,689
			$4,137,705
Secondary Schools – 0.2%
District of Columbia Rev. (Rocketship D.C.), “A”, 5%, 6/01/2039	$	250,000	$258,248
Single Family Housing - Local – 1.0%
Montgomery County, MD, Housing Opportunities Commission Program Rev., “A”, 4%, 7/01/2049	$	550,000	$610,506
Montgomery County, MD, Housing Opportunities Commission, Single Family Mortgage Rev., “A”, FHA, 3.85%, 1/01/2042		430,000	471,482
			$1,081,988
Single Family Housing - State – 3.5%
Connecticut Housing Finance Authority Rev. (Housing Mortgage Finance Program), “D-1”, GNMA, 4%, 11/15/2047	$	480,000	$517,195
Iowa Finance Authority, Single Family Mortgage Rev., “A”, GNMA, 4%, 7/01/2047		485,000	522,209
Maryland Community Development Administration, Department of Housing & Community Development Housing Rev., “A”, 3.75%, 9/01/2039		750,000	822,473
Maryland Community Development Administration, Department of Housing & Community Development Housing Rev., “A”, 4.25%, 9/01/2049		500,000	554,545
Maryland Community Development Administration, Department of Housing & Community Development Rev., “A”, 2.5%, 9/01/2040		750,000	762,990
Pennsylvania Housing Finance Agency, Single Family Mortgage Rev., “125A”, 3.7%, 10/01/2037		530,000	583,355
			$3,762,767

3

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
State & Local Agencies – 5.9%
Colorado State University Board of Governors, System Enterprise Refunding Rev., “E”, 4%, 3/01/2043	$	455,000	$516,944
Delaware Valley, PA, Regional Finance Authority, “C”, FLR, 0.984% (LIBOR - 3mo. + 0.75%), 6/01/2037		665,000	586,463
Howard County, MD, COP, “B”, 8.15%, 2/15/2021		450,000	471,641
Maryland Stadium Authority Rev., Baltimore City Public Schools Construction and Revitalization Program, 5%, 5/01/2041		500,000	575,440
Maryland Stadium Authority Rev., Baltimore City Public Schools Construction and Revitalization Program, “A”, 5%, 5/01/2038		500,000	601,575
Maryland Stadium Authority Rev., Baltimore City Public Schools Construction and Revitalization Program, “A”, 5%, 5/01/2047		335,000	396,342
New Jersey Economic Development Authority Rev., School Facilities Construction Rev., “LLL”, 5%, 6/15/2039		230,000	256,305
New Jersey Economic Development Authority Rev., School Facilities Construction Rev., “LLL”, 5%, 6/15/2044		380,000	418,190
New Jersey Economic Development Authority Rev., School Facilities Construction, “AAA”, 5%, 6/15/2026		100,000	112,921
Prince George's County, MD, COP (Suitland Public Infrastructure), 3%, 10/01/2038		1,000,000	1,078,760
Prince George's County, MD, COP (University of Maryland Capital Region Medical Center), 5%, 10/01/2037		1,000,000	1,268,590
			$6,283,171
Student Loan Revenue – 0.1%
Iowa Student Loan Liquidity Corp. Rev., “B”, 3%, 12/01/2039	$	45,000	$43,883
Iowa Student Loan Liquidity Corp. Rev., “B”, 3.5%, 12/01/2044		115,000	108,935
			$152,818
Tax - Other – 1.0%
Puerto Rico Convention Center District Authority, Hotel Occupancy Tax Rev., “A”, AAC, 5%, 7/01/2031	$	110,000	$110,031
Puerto Rico Infrastructure Financing Authority Special Tax Rev., “C”, AAC, 5.5%, 7/01/2027		635,000	693,286
Virgin Islands Public Finance Authority Rev., Matching Fund Loan Note, “B”, AGM, 5%, 10/01/2025		200,000	207,678
			$1,010,995
Tax Assessment – 4.3%
Baltimore, MD, Special Obligation (East Baltimore Research Park Project), “A”, 5%, 9/01/2038	$	500,000	$515,445
Baltimore, MD, Special Obligation Rev. (Harbor Point Project), “B”, 3.875%, 6/01/2046		300,000	262,926
Brunswick, MD, Special Obligation Refunding (Brunswick Crossing Special Taxing District), 5%, 7/01/2036		500,000	515,355
Frederick County, MD, Limited Obligation (Oakdale-Lake Linganore Project), 3.75%, 7/01/2039		500,000	447,720
Frederick County, MD, Special Obligation (Urbana Community Development Authority), “A”, 5%, 7/01/2040		1,500,000	1,504,380
Howard County, MD, Special Obligation (Annapolis Junction Town Center Project), 6.1%, 2/15/2044		230,000	214,496
Howard County, MD, Special Obligation (Downtown Columbia Project), “A”, 4.5%, 2/15/2047		300,000	294,054
Prince George's County, MD, Special Obligation (National Harbor Project), 5.2%, 7/01/2034		414,000	417,088
Prince George's County, MD, Special Obligation (Westphalia Town Center Project), 5.25%, 7/01/2048		400,000	413,528
			$4,584,992
Tobacco – 1.1%
Buckeye, OH, Tobacco Settlement Financing Authority Senior Asset-Backed Refunding, 2020A-2, “1”, 5%, 6/01/2036	$	75,000	$95,472
Buckeye, OH, Tobacco Settlement Financing Authority Senior Asset-Backed Refunding, 2020A-2, “1”, 4%, 6/01/2048		125,000	135,091
Buckeye, OH, Tobacco Settlement Financing Authority Senior Asset-Backed Refunding, 2020B-2, “2”, 5%, 6/01/2055		530,000	558,085
Buckeye, OH, Tobacco Settlement Financing Authority Senior Asset-Backed Refunding, 2020B-3, Capital Appreciation, “2”, 0%, 6/01/2057		1,400,000	194,348
Illinois Railsplitter Tobacco Settlement Authority Rev., 6%, 6/01/2028 (Prerefunded 6/01/2021)		215,000	226,135
			$1,209,131
Toll Roads – 0.1%
Texas Private Activity Surface Transportation Corp., Senior Lien Rev. (LBJ Infrastructure Group IH-635 Managed Lanes Project), 7%, 6/30/2040	$	135,000	$135,743
Transportation - Special Tax – 5.2%
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “E”, AGM, 5.5%, 7/01/2021	$	50,000	$50,000
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “L”, AAC, 5.25%, 7/01/2038		870,000	902,564
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “L”, NATL, 5.25%, 7/01/2035		170,000	173,342
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, AAC, 5.5%, 7/01/2029		355,000	387,049
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, AAC, 5.25%, 7/01/2031		360,000	380,185
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, NATL, 5.25%, 7/01/2032		200,000	204,042
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, NATL, 5.25%, 7/01/2033		165,000	168,394
Metropolitan Transportation Authority Rev., NY, “E”, 4%, 9/01/2020		155,000	155,273
Metropolitan Transportation Authority Rev., NY, Anticipation Note, “B-2”, 5%, 5/15/2021		365,000	372,629

4

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Transportation - Special Tax – continued
Metropolitan Transportation Authority Rev., NY, Anticipation Note, “D-1”, 5%, 9/01/2022	$	265,000	$278,462
New Jersey Transportation Trust Fund Authority, Transportation System, “A”, 5.25%, 12/15/2021		60,000	62,549
Washington, DC, Metropolitan Area Transit Authority Gross Rev., 5%, 7/01/2037		440,000	532,435
Washington, DC, Metropolitan Area Transit Authority Gross Rev., 5%, 7/01/2038		440,000	531,159
Washington, DC, Metropolitan Area Transit Authority Gross Rev., “B”, 5%, 7/01/2042		1,140,000	1,365,458
			$5,563,541
Universities - Colleges – 7.5%
Maryland Health & Higher Educational Facilities Authority Rev. (Goucher College), “A”, 5%, 7/01/2034	$	500,000	$525,065
Maryland Health & Higher Educational Facilities Authority Rev. (Goucher College), “A”, 5%, 7/01/2044		500,000	563,895
Maryland Health & Higher Educational Facilities Authority Rev. (Johns Hopkins University), “A”, 5%, 7/01/2037		1,500,000	1,635,870
Maryland Health & Higher Educational Facilities Authority Rev. (Loyola University Maryland), 5%, 10/01/2032		500,000	556,130
Maryland Health & Higher Educational Facilities Authority Rev. (Loyola University Maryland), “A”, 5%, 10/01/2049		1,000,000	1,178,140
Maryland Health & Higher Educational Facilities Authority Rev. (Maryland Institute College of Art Issue), 5%, 6/01/2033		450,000	505,170
Maryland Health & Higher Educational Facilities Authority Rev. (Notre Dame College), 5%, 10/01/2035		1,000,000	1,003,080
Morgan State University, Academic & Auxiliary Facilities Fees Rev., 5%, 7/01/2030		150,000	162,729
Morgan State University, Academic & Auxiliary Facilities Fees Rev., 5%, 7/01/2032		440,000	475,693
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority, Higher Education Rev. (Ana G. Mendez University System Project), 5.125%, 4/01/2032		30,000	29,596
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority, Higher Education Rev. (Ana G. Mendez University System Project), 5.375%, 4/01/2042		135,000	132,521
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority, Higher Education Rev. (International American University of Puerto Rico Project), 5%, 10/01/2031		85,000	88,813
University System of Maryland, Auxiliary Facility & Tuition Rev., “D”, 5%, 10/01/2022		1,000,000	1,104,150
Virginia College Building Authority, Educational Facilities Rev. (Marymount University Project), “B”, 5.25%, 7/01/2035		110,000	112,421
			$8,073,273
Universities - Dormitories – 3.2%
California Municipal Finance Authority, Student Housing Rev. (CHF-Davis I LLC - West Village Student Housing Project), BAM, 5%, 5/15/2051	$	660,000	$756,248
Maryland Economic Development Corp., Senior Student Housing Project and Refunding Rev. (Townson University Project), 5%, 7/01/2036		500,000	512,750
Maryland Economic Development Corp., Senior Student Housing Rev. (University of Maryland, College Park Projects), AGM, 5%, 6/01/2035		750,000	855,240
Maryland Economic Development Corp., Student Housing Rev. (Bowie State University Project), 4%, 7/01/2040		500,000	501,570
Maryland Economic Development Corp., Student Housing Rev. (Salisbury University Project), 5%, 6/01/2027		500,000	523,485
Maryland Economic Development Corp., Student Housing Rev. (Salisbury University Project), 5%, 6/01/2030		300,000	312,483
			$3,461,776
Utilities - Cogeneration – 0.2%
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority Rev. (Cogeneration Facilities - AES Puerto Rico Project), 9.12%, 6/01/2022	$	245,000	$251,125
Utilities - Municipal Owned – 0.8%
Puerto Rico Electric Power Authority Rev., “A”, 5%, 7/01/2029 (a)(d)	$	250,000	$173,750
Puerto Rico Electric Power Authority Rev., “A”, 5%, 7/01/2042 (a)(d)		40,000	27,800
Puerto Rico Electric Power Authority Rev., “AAA”, 5.25%, 7/01/2021 (a)(d)		20,000	13,950
Puerto Rico Electric Power Authority Rev., “AAA”, 5.25%, 7/01/2030 (a)(d)		10,000	6,975
Puerto Rico Electric Power Authority Rev., “CCC”, 5.25%, 7/01/2027 (a)(d)		95,000	66,262
Puerto Rico Electric Power Authority Rev., “DDD”, 5%, 7/01/2021 (a)(d)		100,000	69,500
Puerto Rico Electric Power Authority Rev., “DDD”, 5%, 7/01/2021 (a)(d)		10,000	6,950
Puerto Rico Electric Power Authority Rev., “DDD”, 5%, 7/01/2022 (a)(d)		160,000	111,200
Puerto Rico Electric Power Authority Rev., “EEE”, 6.05%, 7/01/2032 (a)(d)		50,000	34,688
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2021 (a)(d)		45,000	31,275
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2023 (a)(d)		40,000	27,800
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2027 (a)(d)		10,000	6,950
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2037 (a)(d)		125,000	86,875
Puerto Rico Electric Power Authority Rev., “VV”, NATL, 5.25%, 7/01/2034		10,000	10,208
Puerto Rico Electric Power Authority Rev., “WW”, 5.375%, 7/01/2022 (a)(d)		10,000	6,988

5

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Utilities - Municipal Owned – continued
Puerto Rico Electric Power Authority Rev., “WW”, 5.25%, 7/01/2025 (a)(d)	$	20,000	$13,950
Puerto Rico Electric Power Authority Rev., “ZZ”, 5%, 7/01/2022 (a)(d)		60,000	41,550
Puerto Rico Electric Power Authority Rev., “ZZ”, 5.25%, 7/01/2023 (a)(d)		65,000	45,256
Puerto Rico Electric Power Authority Rev., “ZZ”, 5.25%, 7/01/2024 (a)(d)		20,000	13,950
Puerto Rico Electric Power Authority Rev., “ZZ”, 5.25%, 7/01/2026 (a)(d)		65,000	45,338
			$841,215
Utilities - Other – 0.8%
Central Plains Energy Project, NE, Gas Project Rev. (Project No. 3), “A”, 5%, 9/01/2036	$	55,000	$71,936
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 9/01/2021		195,000	203,096
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 9/01/2022		100,000	107,620
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 9/01/2023		140,000	155,025
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2/01/2021		235,000	239,554
Texas Gas Acquisition & Supply Corp. III., Gas Supply Rev., 5%, 12/15/2031		55,000	58,438
			$835,669
Water & Sewer Utility Revenue – 6.3%
Baltimore, MD, Project Rev. (Wastewater Projects), “A”, 5%, 7/01/2049	$	1,000,000	$1,260,420
Baltimore, MD, Project Rev. (Water Projects), “A”, 4%, 7/01/2049		1,165,000	1,310,485
Baltimore, MD, Refunding Rev. (Mayor and City Council of Baltimore Water Projects), “B”, 5%, 7/01/2042		1,320,000	1,462,006
Baltimore, MD, Refunding Rev., LEVRRS, NATL, 10.806%, 7/01/2020 (p)		650,000	650,000
Guam Waterworks Authority Rev. (Water and Wastewater System), 5%, 7/01/2036		20,000	22,782
Guam Waterworks Authority Rev. (Water and Wastewater System), 5%, 1/01/2046		105,000	117,638
Guam Waterworks Authority Rev. (Water and Wastewater System), “A”, 5%, 7/01/2029		205,000	229,405
Guam Waterworks Authority Rev. (Water and Wastewater System), “A”, 5%, 7/01/2035		205,000	225,756
Guam Waterworks Authority Rev. (Water and Wastewater System), “A”, 5%, 1/01/2050		130,000	155,117
Michigan Finance Authority Local Government Loan Program Rev. (Detroit Water and Sewerage Department Sewage Disposal System Rev. Refunding Second Lien Local Project), “C-7”, NATL, 5%, 7/01/2032		25,000	28,742
Michigan Finance Authority Local Government Loan Program Rev. (Detroit Water and Sewerage Department Water Supply System Rev. Refunding Second Lien Local Project), “D-6”, NATL, 5%, 7/01/2036		30,000	34,062
Michigan Finance Authority Local Government Loan Program Rev. (Detroit Water and Sewerage Department Water Supply System Rev. Refunding Senior Lien Local Project), “D-1”, AGM, 5%, 7/01/2035		15,000	16,882
Michigan Finance Authority Local Government Loan Program Rev. (Detroit Water and Sewerage Department Water Supply System Rev. Refunding Senior Lien Local Project), “D-1”, AGM, 5%, 7/01/2037		35,000	39,233
Mississippi Development Bank Special Obligation (Jackson Water and Sewer System Rev. Bond Project), AGM, 6.875%, 12/01/2040		50,000	58,712
Montgomery County, MD, Water Quality Protection Charge Rev., “A”, 5%, 4/01/2032		1,125,000	1,128,893
			$6,740,133
Total Municipal Bonds			$105,224,214
Bonds – 0.1%
Consumer Services – 0.1%
Toll Road Investors Partnership II LP, Capital Appreciation, NATL, 0%, 2/15/2043 (n)	$	400,000	$119,247
Investment Companies (h) – 0.3%
Money Market Funds – 0.3%
MFS Institutional Money Market Portfolio, 0.17% (v)		293,795	$293,824
Other Assets, Less Liabilities – 1.4%			1,480,214
Net Assets – 100.0%			$107,117,499

(a)	Non-income producing security.
(d)	In default.
(h)	An affiliated issuer, which 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. At period end, the aggregate values of the fund's investments in affiliated issuers and in unaffiliated issuers were $293,824 and $105,343,461, respectively.

6

Portfolio of Investments (unaudited) – continued

(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 $309,915, representing 0.3% of net assets.
(p)	Primary market inverse floater.
(v)	Affiliated issuer that is available only to investment companies managed by MFS. The rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

The following abbreviations are used in this report and are defined:
AAC	Ambac Assurance Corp.
AGM	Assured Guaranty Municipal
BAM	Build America Mutual
COP	Certificate of Participation
FHA	Federal Housing Administration
FLR	Floating Rate. Interest rate resets periodically based on the parenthetically disclosed reference rate plus a spread (if any). The period-end rate reported may not be the current rate. All reference rates are USD unless otherwise noted.
GNMA	Government National Mortgage Assn.
LEVRRS	Leveraged Reverse Rate Security
LIBOR	London Interbank Offered Rate
NATL	National Public Finance Guarantee Corp.
RIBS	Residual Interest Bonds

Derivative Contracts at 6/30/20
Futures Contracts
Description	Long/ Short	Currency	Contracts	Notional Amount	Expiration Date	Value/Unrealized Appreciation (Depreciation)
Liability Derivatives
Interest Rate Futures
U.S. Treasury Bond	Short	USD	9	$1,607,063	September – 2020	$(8,752)

At June 30, 2020, the fund had cash collateral of $45,000 to cover any collateral or margin obligations for certain derivative contracts.

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

7

Supplemental Information

6/30/20 (unaudited)

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies.

(1) Investment Valuations

Debt instruments and floating rate loans, 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 may be valued at amortized cost, which approximates market value. Futures contracts are generally valued at last posted settlement price on their primary exchange as provided by a third-party pricing service. Futures contracts for which there were no trades that day for a particular position are generally valued at the closing bid quotation on their primary exchange as provided by a third-party pricing service. 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. In determining values, 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 halt 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, such as futures contracts. The following is a summary of the levels used as of June 30, 2020 in valuing the fund's assets or liabilities:

Financial Instruments	Level 1	Level 2	Level 3	Total
Municipal Bonds	$—	$105,224,214	$—	$105,224,214
U.S. Corporate Bonds	—	119,247	—	119,247
Mutual Funds	293,824	—	—	293,824
Total	$293,824	$105,343,461	$—	$105,637,285
Other Financial Instruments
Futures Contracts – Liabilities	$(8,752)	$—	$—	$(8,752)

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

(2) Investments in 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 following were affiliated issuers:

Affiliated Issuers	Beginning Value	Purchases	Sales Proceeds	Realized Gain (Loss)	Change in Unrealized Appreciation or Depreciation	Ending Value
MFS Institutional Money Market Portfolio	$1,796,671	$8,329,844	$9,832,620	$(219)	$148	$293,824

8

Supplemental Information (unaudited) – continued

Affiliated Issuers	Dividend Income	Capital Gain Distributions
MFS Institutional Money Market Portfolio	$1,127	$—

(3) Jurisdiction Weightings

Jurisdiction weighting percentages based on net assets, as of June 30, 2020, are as follows:

Maryland	74.9%
Puerto Rico	7.2%
Washington DC	3.3%
Illinois	1.7%
Tennessee	1.2%
New York	1.2%
Ohio	1.1%
Pennsylvania	1.1%
Guam	1.0%
Colorado	1.0%
New Jersey	0.8%
California	0.7%
Florida	0.6%
South Carolina	0.6%
Iowa	0.6%
Texas	0.5%
Connecticut	0.5%
Massachusetts	0.5%
Alabama	0.3%
Indiana	0.2%
U.S. Virgin Islands	0.2%
Virginia	0.2%
Mississippi	0.1%
Nebraska	0.1%
Michigan	0.1%
U.S. Treasury Securities	(1.5)%

The jurisdiction weighting percentages include both accrued interest amounts and equivalent exposure from any derivatives holdings, if applicable.

(4) Impacts of COVID-19

The pandemic related to the global spread of novel coronavirus disease (COVID-19), which was first detected in December 2019, has resulted in significant disruptions to global business activity and the global economy, as well as the economies of individual countries, the financial performance of individual companies and sectors, and the securities and commodities markets in general. This pandemic, the full effects of which are still unknown, has resulted in substantial market volatility and may have adversely impacted the prices and liquidity of the fund's investments and the fund's performance.

9