Quarterly Report

December 31, 2019

MFS^® West Virginia
Municipal Bond Fund

Portfolio of Investments

12/31/19 (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 – 98.5%
Airport Revenue – 1.3%
Dallas and Fort Worth, TX, International Airport Rev., “B”, 5%, 11/01/2044	$	155,000	$169,638
Dallas and Fort Worth, TX, International Airport Rev., “C”, 5%, 11/01/2045		110,000	116,952
New York Transportation Development Corp., Special Facilities Rev. (LaGuardia Airport Terminal B Redevelopment Project), “A”, AGM, 4%, 7/01/2037		745,000	793,462
Wayne County, MI, Airport Authority Rev. (Detroit Metropolitan Wayne County Airport), “B”, 5%, 12/01/2044		60,000	68,222
Wayne County, MI, Airport Authority Rev. (Detroit Metropolitan Wayne County Airport), “B”, BAM, 5%, 12/01/2039		70,000	80,975
Wayne County, MI, Airport Authority Rev. (Detroit Metropolitan Wayne County Airport), “C”, 5%, 12/01/2039		55,000	62,235
Wayne County, MI, Airport Authority Rev. (Detroit Metropolitan Wayne County Airport), “C”, 5%, 12/01/2044		85,000	95,590
			$1,387,074
General Obligations - General Purpose – 9.1%
Bridgeview, IL, Stadium and Redevelopment Projects, AAC, 5.14%, 12/01/2036	$	260,000	$263,008
Chicago, IL, “B”, 7.375%, 1/01/2033		283,000	339,000
Commonwealth of Puerto Rico, Public Improvement, “A-4”, AGM, 5%, 7/01/2031		95,000	96,074
State of West Virginia, 4%, 6/01/2022		1,750,000	1,770,948
State of West Virginia, 4%, 6/01/2023		2,000,000	2,023,840
State of West Virginia, General Obligation Road Bonds, “B”, 4%, 12/01/2042		1,000,000	1,111,980
State of West Virginia, General Obligation Road Bonds, “B”, 4%, 6/01/2043		2,825,000	3,138,179
West Virginia State Road General Obligation, “A”, 5%, 6/01/2044		1,000,000	1,229,860
			$9,972,889
General Obligations - Schools – 6.6%
Hancock County, WV, Board of Education, Public School General Obligation, 4.5%, 5/01/2032	$	1,405,000	$1,467,775
Monongalia County, WV, Board of Education, 5%, 5/01/2031		2,000,000	2,178,740
Putnam County, WV, Board of Education, 4%, 5/01/2020		2,500,000	2,523,950
Putnam County, WV, Board of Education, 4%, 5/01/2025		1,000,000	1,009,170
			$7,179,635
Healthcare Revenue - Hospitals – 18.4%
Allegheny County, PA, Hospital Development Authority Rev. (Allegheny Health Network Obligated Group), “A”, 4%, 4/01/2044	$	190,000	$203,353
Doylestown, PA, Hospital Rev., “A”, 4%, 7/01/2045		15,000	15,656
Escambia County, FL, Health Facilities Authority (Baptist Hospital, Inc.), “A”, 6%, 8/15/2036		725,000	743,799
Illinois Finance Authority Rev. (Provena Health), “A”, 6%, 5/01/2028 (Prerefunded 5/01/2020)		450,000	457,142
Kentucky Economic Development Finance Authority Hospital Rev. (Owensboro Medical Health System, Inc.), “A”, 5.75%, 6/01/2025 (Prerefunded 6/01/2020)		340,000	346,362
Kentucky Economic Development Finance Authority Hospital Rev. (Owensboro Medical Health System, Inc.), “A”, 6.375%, 6/01/2040 (Prerefunded 6/01/2020)		410,000	418,704
Kentucky Economic Development Finance Authority Hospital Rev. (Owensboro Medical Health System, Inc.), “A”, 6.5%, 3/01/2045 (Prerefunded 6/01/2020)		290,000	296,293
Monongalia County, WV, Building Commission Hospital Rev. (Monongalia General Hospital), 6.5%, 7/01/2041		1,100,000	1,176,560
Monongalia County, WV, Building Commission Improvement Rev. (Monongalia Health System Obligated Group), 5%, 7/01/2029		1,000,000	1,117,450
Spartanburg County, SC, Regional Health Services District Hospital Rev., “A”, 4%, 4/15/2043		780,000	832,393
West Virginia Hospital Finance Authority Hospital Improvement Rev. (Charleston Area Medical Center, Inc.), “A”, 5%, 9/01/2039		1,500,000	1,810,335
West Virginia Hospital Finance Authority Hospital Rev. (Cabell Huntington Hospital Obligated Group), “A”, 4.125%, 1/01/2047		1,000,000	1,063,670
West Virginia Hospital Finance Authority Hospital Rev. (Charleston Area Medical Center), “A”, 5%, 9/01/2028		1,000,000	1,133,950
West Virginia Hospital Finance Authority Hospital Rev. (Charleston Area Medical Center), “A”, ETM, 6.5%, 9/01/2023		1,250,000	1,384,300
West Virginia Hospital Finance Authority Hospital Rev. (Thomas Health System), 6.5%, 10/01/2038 (a)(d)		500,000	292,500
West Virginia Hospital Finance Authority Hospital Rev. (Valley Health System Obligation Group), 5%, 1/01/2044		1,000,000	1,082,410
West Virginia Hospital Finance Authority Hospital Rev. (Valley Health System Obligation Group), 5%, 1/01/2044		1,000,000	1,115,090
West Virginia Hospital Finance Authority Hospital Rev. (West Virginia United Health System Obligated Group), “A”, 4%, 6/01/2035		1,500,000	1,644,330
West Virginia Hospital Finance Authority Hospital Rev. (West Virginia United Health System Obligated Group), “A”, 5.5%, 6/01/2044		1,460,000	1,621,359
West Virginia Hospital Finance Authority Hospital Rev. (West Virginia United Health System Obligated Group), “A”, AGM, 4%, 6/01/2051		2,000,000	2,188,720

1

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Healthcare Revenue - Hospitals – continued
West Virginia Hospital Finance Authority Hospital Rev. (West Virginia University Health System Obligated Group), “A”, 5%, 6/01/2042	$	1,000,000	$1,167,340
			$20,111,716
Industrial Revenue - Other – 0.9%
New York Liberty Development Corp. Rev. (Goldman Sachs Headquarters), 5.25%, 10/01/2035	$	420,000	$571,754
Tuscaloosa County, AL, Industrial Development Authority, Gulf Opportunity Zone (Hunt Refining Project), “A”, 5.25%, 5/01/2044		325,000	373,542
			$945,296
Miscellaneous Revenue - Other – 8.3%
Florida Citizens Property Insurance Corp., “A-1”, 5%, 6/01/2020	$	605,000	$614,444
Indiana Finance Authority Rev. (Ohio River Bridges East End Crossing Project), “A”, 5%, 7/01/2040		140,000	153,329
Indiana Finance Authority Rev. (Ohio River Bridges East End Crossing Project), “A”, 5%, 7/01/2044		215,000	235,107
New York Liberty Development Corp., Liberty Rev. (3 World Trade Center Project), “1”, 5%, 11/15/2044		580,000	640,993
New York Liberty Development Corp., Liberty Rev. (7 World Trade Center Project), 5%, 9/15/2040		545,000	586,311
West Virginia Economic Development Authority, Excess Lottery Rev., “A”, 5%, 7/01/2038		1,000,000	1,214,360
West Virginia Economic Development Authority, Lottery Rev., “A”, 5%, 6/15/2040 (Prerefunded 6/15/2020)		2,475,000	2,518,535
West Virginia School Building Authority, “A”, 3%, 7/01/2033		2,000,000	2,087,600
West Virginia School Building Authority, Excess Lottery Rev., “B”, 5%, 7/01/2030		1,000,000	1,018,280
			$9,068,959
Sales & Excise Tax Revenue – 5.0%
Chicago, IL, Transit Authority Sales Tax Receipts Rev., AGM, 5%, 12/01/2046	$	825,000	$948,420
Guam Government Business Privilege Tax Rev., “A”, 5.25%, 1/01/2036		335,000	352,370
Guam Government Business Privilege Tax Rev., “A”, 5.125%, 1/01/2042		790,000	823,828
Massachusetts Bay Transportation Authority, Sales Tax Rev., “A”, 5%, 7/01/2031		500,000	666,935
Ohio County, WV, Commission Special District Excise Tax Improvement Refunding Rev. (Fort Henry Economic Opportunity Development District - The Highlands Project), “B”, 2.75%, 3/01/2041		750,000	746,385
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-1”, 4.55%, 7/01/2040		25,000	25,883
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-1”, 4.75%, 7/01/2053		408,000	425,960
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-1”, 5%, 7/01/2058		415,000	440,328
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.329%, 7/01/2040		238,000	241,265
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.329%, 7/01/2040		83,000	84,139
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.536%, 7/01/2053		1,000	1,022
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., “2019A-2”, 4.784%, 7/01/2058		39,000	40,507
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2024		3,000	2,633
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2027		45,000	35,932
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2029		7,000	5,194
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2031		412,000	282,867
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2033		396,000	251,927
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2046		186,000	49,831
Puerto Rico Sales Tax Financing Corp., Restructured Sales Tax Rev., Capital Appreciation, “2019A-1”, 0%, 7/01/2051		233,000	45,475
			$5,470,901
Single Family Housing - State – 2.3%
West Virginia Housing Development Fund, “A”, 3.8%, 11/01/2024	$	30,000	$30,139
West Virginia Housing Development Fund, “A”, 3.875%, 11/01/2044		1,500,000	1,605,915
West Virginia Housing Development Fund, “A”, FHA, 3.9%, 11/01/2048		800,000	847,168
			$2,483,222
State & Local Agencies – 7.4%
Maryland Stadium Authority Rev., Baltimore City Public Schools Construction and Revitalization Program, “A”, 5%, 5/01/2047	$	400,000	$478,980
North Carolina Turnpike Authority, Triangle Expressway System Appropriation Rev., Capital Appreciation, 0%, 1/01/2044		1,640,000	793,826
West Virginia Economic Development Authority, Auto Lease Rev., 5.2%, 5/01/2033		1,000,000	1,001,500
West Virginia Economic Development Authority, Lease Rev. (Correctional Juvenile Public Safety Facilities), 5%, 6/01/2022		1,000,000	1,052,270
West Virginia Economic Development Authority, Lease Rev. (Correctional Juvenile Public Safety Facilities), “A”, 5%, 6/01/2029		2,000,000	2,163,620
West Virginia Economic Development Authority, Lease Rev. (State Office Building), “B”, NATL, 5.25%, 1/01/2025		490,000	491,607
West Virginia Economic Development Authority, Lease Rev. (State Office Building), “B”, NATL, 5.25%, 1/01/2030		1,355,000	1,359,445

2

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
State & Local Agencies – continued
West Virginia Hospital Finance Authority Hospital Rev. (Veterans Nursing Home), 5.5%, 3/01/2034	$	795,000	$796,876
			$8,138,124
Tax - Other – 3.0%
Birmingham-Jefferson, AL, Civic Center Authority, “B”, 5%, 7/01/2043	$	535,000	$634,960
Puerto Rico Convention Center District Authority, Hotel Occupancy Tax Rev., “A”, AAC, 5%, 7/01/2031		945,000	965,809
Puerto Rico Infrastructure Financing Authority Special Tax Rev., “C”, AAC, 5.5%, 7/01/2026		95,000	105,195
Puerto Rico Infrastructure Financing Authority Special Tax Rev., “C”, AAC, 5.5%, 7/01/2027		430,000	477,863
Virgin Islands Public Finance Authority Rev. (Gross Receipts), AGM, 5%, 10/01/2032		1,000,000	1,086,690
			$3,270,517
Tax Assessment – 1.3%
Morgantown, WV, Tax Increment Rev., Parking Garage Project, “A”, 5%, 6/01/2033	$	455,000	$455,132
Ohio County, WV, Commission Tax Increment Rev. (Fort Henry Centre), 4%, 6/01/2034		1,000,000	1,021,430
			$1,476,562
Tobacco – 0.6%
Illinois Railsplitter Tobacco Settlement Authority Rev., 6%, 6/01/2028 (Prerefunded 6/01/2021)	$	620,000	$662,327
Toll Roads – 1.3%
Texas Private Activity Surface Transportation Corp., Senior Lien Rev. (NTE Mobility Partners Segments 3 LLC Segments 3A & 3B Facility), 7%, 12/31/2038	$	155,000	$181,265
Texas Private Activity Surface Transportation Corp., Senior Lien Rev. (NTE Mobility Partners Segments 3 LLC Segments 3A & 3B Facility), 6.75%, 6/30/2043		120,000	138,825
West Virginia Parkways Authority, Turnpike Toll Rev., 4%, 6/01/2047		1,000,000	1,099,350
			$1,419,440
Transportation - Special Tax – 3.0%
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “AA-1”, AGM, 4.95%, 7/01/2026	$	575,000	$580,687
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “L”, AAC, 5.25%, 7/01/2038		755,000	822,180
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “L”, ASSD GTY, 5.25%, 7/01/2041		225,000	253,505
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “L”, NATL, 5.25%, 7/01/2035		340,000	368,818
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, AAC, 5.5%, 7/01/2029		760,000	845,470
Commonwealth of Puerto Rico Highway & Transportation Authority Rev., “N”, NATL, 5.25%, 7/01/2032		115,000	125,594
New Jersey Transportation Trust Fund Authority, Federal Highway Reimbursement Rev., “A-1”, 5%, 6/15/2027		220,000	259,690
			$3,255,944
Universities - Colleges – 13.9%
Fairmont State University, WV, Board of Governors Rev., “A”, 5%, 6/01/2032	$	4,035,000	$4,229,971
Marshall University, WV, University Rev., 5%, 5/01/2030		2,000,000	2,023,620
Marshall University, WV, University Rev., 5%, 5/01/2041		1,000,000	1,045,060
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority, Educational Facilities Rev. (University Plaza), “A”, NATL, 5%, 7/01/2021		1,270,000	1,285,634
Puerto Rico Industrial, Tourist, Educational, Medical & Environmental Control Facilities Financing Authority, Higher Education Rev. (Ana G. Mendez University System Project), 5.375%, 12/01/2021		5,000	4,995
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		110,000	114,875
West Virginia University, Board of Governors Improvement Rev. (West Virginia University Project), “A”, 5%, 10/01/2049		1,000,000	1,223,810
West Virginia University, University Systems Rev., “A”, NATL, 5.5%, 4/01/2020		1,700,000	1,718,003
West Virginia University, University Systems Rev., “A”, NATL, 5.25%, 4/01/2028		3,035,000	3,575,048
			$15,221,016
Utilities - Investor Owned – 0.4%
Michigan Strategic Fund Ltd. Obligation Rev. (Detroit Edison Co.), 5.625%, 7/01/2020	$	470,000	$479,607
Utilities - Municipal Owned – 1.6%
Guam Power Authority Rev., “A”, 5.5%, 10/01/2030 (Prerefunded 10/01/2020)	$	325,000	$335,517
Guam Power Authority Rev., “A”, AGM, 5%, 10/01/2033		435,000	494,116
Puerto Rico Electric Power Authority Rev., “A”, 5%, 7/01/2029 (a)(d)		275,000	208,312

3

Portfolio of Investments (unaudited) – continued

Issuer		Shares/Par	Value ($)
Municipal Bonds – continued
Utilities - Municipal Owned – continued
Puerto Rico Electric Power Authority Rev., “A”, 5%, 7/01/2042 (a)(d)	$	45,000	$34,088
Puerto Rico Electric Power Authority Rev., “CCC”, 5.25%, 7/01/2027 (a)(d)		75,000	57,000
Puerto Rico Electric Power Authority Rev., “DDD”, 5%, 7/01/2021 (a)(d)		95,000	71,963
Puerto Rico Electric Power Authority Rev., “DDD”, 5%, 7/01/2022 (a)(d)		180,000	136,350
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2023 (a)(d)		50,000	37,875
Puerto Rico Electric Power Authority Rev., “TT”, 5%, 7/01/2037 (a)(d)		145,000	109,838
Puerto Rico Electric Power Authority Rev., “VV”, NATL, 5.25%, 7/01/2030		135,000	147,174
Puerto Rico Electric Power Authority Rev., “VV”, NATL, 5.25%, 7/01/2034		10,000	10,916
Puerto Rico Electric Power Authority Rev., “ZZ”, 5%, 7/01/2022 (a)(d)		70,000	51,800
Puerto Rico Electric Power Authority Rev., “ZZ”, 5.25%, 7/01/2023 (a)(d)		75,000	57,000
			$1,751,949
Utilities - Other – 1.6%
California M-S-R Energy Authority Gas Rev., “A”, 6.5%, 11/01/2039	$	615,000	$961,435
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 9/01/2021		245,000	259,798
Tennessee Energy Acquisition Corp., Gas Rev., “A”, 5.25%, 9/01/2022		125,000	136,660
Tennessee Energy Acquisition Corp., Gas Rev., “C”, 5%, 2/01/2021		290,000	300,617
Texas Gas Acquisition & Supply Corp. III., Gas Supply Rev., 5%, 12/15/2031		70,000	76,273
			$1,734,783
Water & Sewer Utility Revenue – 12.5%
Berkeley County, WV, Public Service Sewer District, “A”, BAM, 5%, 6/01/2036	$	1,700,000	$1,993,998
Fairmont, WV, Waterworks Rev., AAC, 5.25%, 7/01/2022		200,000	210,598
Guam Waterworks Authority Rev. (Water and Wastewater System), 5%, 7/01/2036		40,000	45,740
Guam Waterworks Authority Rev. (Water and Wastewater System), 5.625%, 7/01/2040 (Prerefunded 7/01/2020)		515,000	526,716
Guam Waterworks Authority Rev. (Water and Wastewater System), 5%, 1/01/2046		180,000	202,270
Guam Waterworks Authority Rev. (Water and Wastewater System), “A”, 5%, 7/01/2029		20,000	22,360
Guam Waterworks Authority Rev. (Water and Wastewater System), “A”, 5%, 7/01/2035		20,000	22,072
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		35,000	39,753
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		40,000	45,179
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		20,000	22,708
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		50,000	56,458
Mississippi Development Bank Special Obligation (City of Jackson Water and Sewer System Rev. Bond Project), AGM, 6.875%, 12/01/2040		75,000	88,665
Morgantown, WV, Combined Utility System Rev., “A”, AGM, 5%, 12/01/2041		1,000,000	1,170,420
Morgantown, WV, Combined Utility System Rev., “B”, 5%, 12/01/2043		2,000,000	2,400,220
West Virginia Water Development Authority Rev. (Loan Program II), “A-II”, 5%, 11/01/2033		1,475,000	1,762,669
West Virginia Water Development Authority Rev. (Loan Program IV), “A-IV”, ETM, 5%, 11/01/2038		500,000	608,620
Wheeling, WV, Combined Waterworks and Sewerage System Rev., 5%, 6/01/2038		3,000,000	3,306,300
Wheeling, WV, Combined Waterworks and Sewerage System Rev., 5%, 6/01/2043		1,000,000	1,099,530
			$13,624,276
Total Municipal Bonds			$107,654,237
Bonds – 0.1%
Consumer Services – 0.1%
Toll Road Investors Partnership II LP, Capital Appreciation, NATL, 0%, 2/15/2043 (n)	$	400,000	$116,865
Investment Companies (h) – 0.7%
Money Market Funds – 0.7%
MFS Institutional Money Market Portfolio, 1.7% (v)		743,755	$743,755
Other Assets, Less Liabilities – 0.7%			786,411
Net Assets – 100.0%			$109,301,268

4

Portfolio of Investments (unaudited) – continued

(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 $743,755 and $107,771,102, respectively.
(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 $116,865, representing 0.1% of net assets.
(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
ASSD GTY	Assured Guaranty Insurance Co.
BAM	Build America Mutual
ETM	Escrowed to Maturity
FHA	Federal Housing Administration
NATL	National Public Finance Guarantee Corp.

Derivative Contracts at 12/31/19
Futures Contracts
Description	Long/ Short	Currency	Contracts	Notional Amount	Expiration Date	Value/Unrealized Appreciation (Depreciation)
Liability Derivatives
Interest Rate Futures
U.S. Treasury Bond	Long	USD	14	$2,182,688	March – 2020	$(55,282)

At December 31, 2019, the fund had cash collateral of $37,800 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.

5

Supplemental Information

12/31/19 (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 December 31, 2019 in valuing the fund's assets or liabilities:

Financial Instruments	Level 1	Level 2	Level 3	Total
Municipal Bonds	$—	$107,654,237	$—	$107,654,237
U.S. Corporate Bonds	—	116,865	—	116,865
Mutual Funds	743,755	—	—	743,755
Total	$743,755	$107,771,102	$—	$108,514,857
Other Financial Instruments
Futures Contracts – Liabilities	$(55,282)	$—	$—	$(55,282)

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	$518,129	$15,025,756	$14,799,950	$(128)	$(52)	$743,755

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Supplemental Information (unaudited) – continued

Affiliated Issuers	Dividend Income	Capital Gain Distributions
MFS Institutional Money Market Portfolio	$14,136	$—

(3) Jurisdiction Weightings

Jurisdiction weighting percentages based on net assets, as of December 31, 2019, are as follows:

West Virginia	73.0%
Puerto Rico	8.3%
Guam	2.6%
Illinois	2.5%
New York	2.4%
Florida	1.3%
Kentucky	1.0%
U.S. Virgin Islands	1.0%
Alabama	0.9%
California	0.9%
Michigan	0.9%
South Carolina	0.8%
North Carolina	0.7%
Massachusetts	0.6%
Tennessee	0.6%
Texas	0.6%
Indiana	0.4%
Maryland	0.4%
New Jersey	0.2%
Pennsylvania	0.2%
Mississippi	0.1%
Virginia	0.1%

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

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