{
  "page": "compare",
  "query": {
    "a": "MMDIX",
    "b": "MFIAX"
  },
  "retrieved_at": "2026-07-07T18:25:20+00:00",
  "disclaimer": "Informational only — not investment advice. FundWatcher presents publicly available data and makes no recommendation to buy or sell any security. Verify all figures against the source filing before relying on them.",
  "attribution": "Data sourced from U.S. SEC EDGAR filings (Forms N-PORT, N-CEN, and prospectus Risk/Return summaries). FundWatcher is not affiliated with the SEC.",
  "terms": {
    "notice": "Use of this data is subject to the FundWatcher Terms of Service. Information may be used only for personal, non-commercial research and may not be redistributed.",
    "url": "https://fundwatcher.app/terms/"
  },
  "fund_a": {
    "name": "MFS Maryland Municipal Bond Fund",
    "ticker": "MMDIX",
    "slug": "MMDIX",
    "series_id": "S000002533",
    "html_url": "https://fundwatcher.app/funds/MMDIX/"
  },
  "fund_b": {
    "name": "MFS Municipal Income Fund",
    "ticker": "MFIAX",
    "slug": "MFIAX",
    "series_id": "S000002536",
    "html_url": "https://fundwatcher.app/funds/MFIAX/"
  },
  "overlap": {
    "coverage_a_by_b": "0.08626528760095164889494085740",
    "coverage_b_by_a": "0.08626528760095164889494085742",
    "shared_count": 71,
    "as_of": {
      "a": "2026-03-31",
      "b": "2026-03-31"
    },
    "a_top": [
      {
        "name": "MFS Institutional Money Market Portfolio, Class A",
        "value": "5117103.28",
        "weight": "0.03287827",
        "shared": true
      },
      {
        "name": "MARYLAND ST ECON DEV CORP LEASE REVENUE",
        "value": "2066416.60",
        "weight": "0.01327708",
        "shared": false
      },
      {
        "name": "Maryland Economic Development Corp., Series 2024",
        "value": "1956308.20",
        "weight": "0.01256962",
        "shared": false
      },
      {
        "name": "Montgomery (County of), MD, Series 2017, GO Bonds",
        "value": "1900000.00",
        "weight": "0.01220783",
        "shared": false
      },
      {
        "name": "MARYLAND ST STD 5% 5/1/2035",
        "value": "1785164.72",
        "weight": "0.01146999",
        "shared": false
      },
      {
        "name": "PUERTO RICO SALES TAX FING COR REGD OID B/E 5.00000000",
        "value": "1727325.78",
        "weight": "0.01109837",
        "shared": true
      },
      {
        "name": "County of Prince George's, Series 2025 A",
        "value": "1607726.55",
        "weight": "0.01032992",
        "shared": false
      },
      {
        "name": "Washington Metropolitan Area Transit Authority Dedicated",
        "value": "1607187.60",
        "weight": "0.01032646",
        "shared": false
      },
      {
        "name": "Maryland Stadium Authority, Series 2024",
        "value": "1571792.40",
        "weight": "0.01009904",
        "shared": false
      },
      {
        "name": "County of Anne Arundel, Series 2025",
        "value": "1562597.40",
        "weight": "0.01003996",
        "shared": false
      },
      {
        "name": "MD HLTH & HGR EDL-A",
        "value": "1561890.15",
        "weight": "0.01003541",
        "shared": false
      },
      {
        "name": "Maryland Health & Higher Educational Facilities Authority",
        "value": "1554150.45",
        "weight": "0.00998568",
        "shared": false
      },
      {
        "name": "PRINCE GEO COP 5% 10/1/48",
        "value": "1524666.75",
        "weight": "0.00979625",
        "shared": false
      },
      {
        "name": "Maryland Community Development Administration, Series 2025 F-1",
        "value": "1506350.25",
        "weight": "0.00967856",
        "shared": false
      },
      {
        "name": "MARYLAND STADIUM AUTHORITY",
        "value": "1492435.35",
        "weight": "0.00958915",
        "shared": false
      },
      {
        "name": "WASHINGTON SUBURBAN SANITARY COMMISSION",
        "value": "1461898.35",
        "weight": "0.00939295",
        "shared": false
      },
      {
        "name": "COUNTY OF BALTIMORE MD",
        "value": "1457850.60",
        "weight": "0.00936694",
        "shared": false
      },
      {
        "name": "County of Howard",
        "value": "1424096.70",
        "weight": "0.00915007",
        "shared": false
      },
      {
        "name": "MARYLAND ST HLTH & HGR EDUCTNL FACS AUTH REVENUE",
        "value": "1406792.17",
        "weight": "0.00903888",
        "shared": false
      },
      {
        "name": "Maryland Health & Higher Educational Facilities Authority, Series 2004",
        "value": "1396223.21",
        "weight": "0.00897098",
        "shared": false
      },
      {
        "name": "County of Anne Arundel, Series 2023",
        "value": "1393211.60",
        "weight": "0.00895163",
        "shared": false
      },
      {
        "name": "City of Baltimore, Series 2019 A",
        "value": "1392087.02",
        "weight": "0.00894440",
        "shared": false
      },
      {
        "name": "Maryland Community Development Administration Department of Housing and Community Development, Residential Revenue Bonds, Taxable Series 2019D",
        "value": "1391971.66",
        "weight": "0.00894366",
        "shared": false
      },
      {
        "name": "MARYLAND ST STA 4% 6/1/2046",
        "value": "1314577.29",
        "weight": "0.00844639",
        "shared": false
      },
      {
        "name": "MARYLAND HEALTH & HIGHER EDUCATIONAL FACILITIES AUTHORITY",
        "value": "1288038.33",
        "weight": "0.00827587",
        "shared": false
      },
      {
        "name": "Maryland Health & Higher Educational Facilities Authority",
        "value": "1260651.72",
        "weight": "0.00809990",
        "shared": false
      },
      {
        "name": "MONTGOMERY CNTY MD REVENUE REGD B/E 5.00000000",
        "value": "1240317.19",
        "weight": "0.00796925",
        "shared": false
      },
      {
        "name": "Maryland Community Development Administration Local Government Infrastructure",
        "value": "1230218.13",
        "weight": "0.00790436",
        "shared": false
      },
      {
        "name": "MD CMNTY DEV-D-1",
        "value": "1190841.13",
        "weight": "0.00765136",
        "shared": false
      },
      {
        "name": "Washington Metropolitan Area Transit Authority, Series 2018, RB",
        "value": "1155596.68",
        "weight": "0.00742491",
        "shared": false
      },
      {
        "name": "MD HEFA 4% 7/1/2048",
        "value": "1108365.50",
        "weight": "0.00712144",
        "shared": false
      },
      {
        "name": "County of Montgomery",
        "value": "1107250.70",
        "weight": "0.00711428",
        "shared": false
      },
      {
        "name": "MD CMNTY DEPT ADMIN-B",
        "value": "1097910.15",
        "weight": "0.00705426",
        "shared": false
      },
      {
        "name": "Maryland Health & Higher Educational Facilities Authority",
        "value": "1094371.76",
        "weight": "0.00703153",
        "shared": false
      },
      {
        "name": "CALIFORNIA COMMUNITY VAR",
        "value": "1081998.20",
        "weight": "0.00695203",
        "shared": false
      },
      {
        "name": "MD TRANSPRTN-A-REF",
        "value": "1080306.40",
        "weight": "0.00694116",
        "shared": false
      },
      {
        "name": "Montgomery County Housing Opportunities Commission, Series 2023 C",
        "value": "1076666.80",
        "weight": "0.00691777",
        "shared": false
      },
      {
        "name": "Maryland Department of Housing & Community Development, Series 2024 E",
        "value": "1076506.43",
        "weight": "0.00691674",
        "shared": true
      },
      {
        "name": "MD ECON DEV CORP-A",
        "value": "1072393.30",
        "weight": "0.00689031",
        "shared": false
      },
      {
        "name": "County of Prince George's",
        "value": "1040425.00",
        "weight": "0.00668491",
        "shared": false
      },
      {
        "name": "MARYLAND ST ECON DEV CORP AIR CARGO REVENUE",
        "value": "1040054.84",
        "weight": "0.00668253",
        "shared": false
      },
      {
        "name": "Washington Metropolitan Area Transit Authority, Series 2025, RB",
        "value": "1038645.70",
        "weight": "0.00667348",
        "shared": false
      },
      {
        "name": "Maryland Stadium Authority Sports Entertainment Facilities Revenue, Series 2023 A",
        "value": "1034419.30",
        "weight": "0.00664632",
        "shared": false
      },
      {
        "name": "State of Maryland Department of Transportation, Series 2024 A",
        "value": "1032954.50",
        "weight": "0.00663691",
        "shared": false
      },
      {
        "name": "MARYLAND ST HLTH & HGR EDUCTNL MARYLAND HEALTH & HIGHER EDUCATIONAL FACILITIES AU",
        "value": "1031303.10",
        "weight": "0.00662630",
        "shared": false
      },
      {
        "name": "MARYLAND ST HLTH & HGR EDUCTNL FACS AUTH REVENUE",
        "value": "1025953.80",
        "weight": "0.00659193",
        "shared": false
      },
      {
        "name": "Maryland Department of Housing & Community Development, Series 2025 D",
        "value": "1024100.00",
        "weight": "0.00658002",
        "shared": false
      },
      {
        "name": "State of Maryland Department of Transportation, Series 2024 A",
        "value": "1023701.30",
        "weight": "0.00657746",
        "shared": true
      },
      {
        "name": "MARYLAND ST STA 4% 6/1/2036",
        "value": "1022381.10",
        "weight": "0.00656898",
        "shared": false
      },
      {
        "name": "Montgomery County Housing Opportunities Commission, Series 2025A",
        "value": "1021211.30",
        "weight": "0.00656146",
        "shared": false
      }
    ],
    "b_top": [
      {
        "name": "MFS Institutional Money Market Portfolio, Class A",
        "value": "168421496.15",
        "weight": "0.02436056",
        "shared": true
      },
      {
        "name": "Black Belt Energy Gas District",
        "value": "36524672.64",
        "weight": "0.00528294",
        "shared": false
      },
      {
        "name": "TEXAS ST MUNI GAS ACQUISITION& TEXAS MUNICIPAL GAS ACQUISITION & SUPPLY CORP IV",
        "value": "32484690.97",
        "weight": "0.00469860",
        "shared": false
      },
      {
        "name": "PRINCETON TX INDEP SCH DIST",
        "value": "29636666.36",
        "weight": "0.00428666",
        "shared": false
      },
      {
        "name": "NY TRANS CORP(JFK INT NEW ONE)/AGM 5.25% 6/30/60@",
        "value": "29151826.25",
        "weight": "0.00421653",
        "shared": false
      },
      {
        "name": "NY TRANS CORP(JFK INT NEW ONE)/AGM 5.13% 6/30/60@",
        "value": "29039960.93",
        "weight": "0.00420035",
        "shared": true
      },
      {
        "name": "New Hampshire Business Finance Authority, Series 2023A",
        "value": "28620989.28",
        "weight": "0.00413975",
        "shared": false
      },
      {
        "name": "California (State of) Community Choice Financing Authority (Green Bonds), Series 2023 C, RB",
        "value": "27756824.19",
        "weight": "0.00401476",
        "shared": true
      },
      {
        "name": "BLACK BELT ENGY GAS-C",
        "value": "25083362.48",
        "weight": "0.00362807",
        "shared": false
      },
      {
        "name": "NOVANT HEALTH OBLIGATED GROUP 5.5% 06-01-50",
        "value": "24283162.58",
        "weight": "0.00351233",
        "shared": false
      },
      {
        "name": "PUERTO RICO SALES TAX FING COR REGD OID B/E 5.00000000",
        "value": "23202443.77",
        "weight": "0.00335601",
        "shared": true
      },
      {
        "name": "VIRGINIA ST HSG DEV AUTH",
        "value": "21825945.31",
        "weight": "0.00315691",
        "shared": false
      },
      {
        "name": "PENNSYLVANIA ST ECON DEV FING REGD OID B/E AMT AG 5.00000000",
        "value": "21811357.13",
        "weight": "0.00315480",
        "shared": true
      },
      {
        "name": "QUEEN CREEK AZ COPS",
        "value": "21660973.28",
        "weight": "0.00313305",
        "shared": false
      },
      {
        "name": "Connecticut State Health & Educational Facilities Authority, Series A",
        "value": "21380008.00",
        "weight": "0.00309241",
        "shared": false
      },
      {
        "name": "METROCARE SVC REV",
        "value": "21222926.80",
        "weight": "0.00306969",
        "shared": false
      },
      {
        "name": "NY TRANSPRTN DEV CORP",
        "value": "20732607.80",
        "weight": "0.00299877",
        "shared": false
      },
      {
        "name": "MD HLTH HGR AUTH-A",
        "value": "20554628.00",
        "weight": "0.00297303",
        "shared": false
      },
      {
        "name": "WV HOSP 5.375% 9/1/2053",
        "value": "20473933.37",
        "weight": "0.00296136",
        "shared": false
      },
      {
        "name": "TENNERGY CORP TN GAS REVENUE TGYPWR 10/53 ADJUSTABLE VAR",
        "value": "20436540.28",
        "weight": "0.00295595",
        "shared": true
      },
      {
        "name": "JEA WTR & SWR REV-A",
        "value": "20427563.65",
        "weight": "0.00295465",
        "shared": false
      },
      {
        "name": "Black Belt Energy Gas District, Series 2025 A",
        "value": "20107281.45",
        "weight": "0.00290833",
        "shared": false
      },
      {
        "name": "Delaware State Housing Authority, Series BDS 2023",
        "value": "19927531.01",
        "weight": "0.00288233",
        "shared": false
      },
      {
        "name": "TX PRIVATE ACTIVITY",
        "value": "19277807.52",
        "weight": "0.00278835",
        "shared": false
      },
      {
        "name": "Energy Southeast Cooperative District, Alabama, Energy Supply Revenue Bonds, Series 2025B",
        "value": "19241087.03",
        "weight": "0.00278304",
        "shared": false
      },
      {
        "name": "Alachua County Health Facilities Authority, Series 2025 A",
        "value": "19131332.09",
        "weight": "0.00276716",
        "shared": false
      },
      {
        "name": "Southeast Energy Authority, Alabama, Commodity Supply Revenue Bonds, Project 5, Series 2023A",
        "value": "19051853.45",
        "weight": "0.00275567",
        "shared": true
      },
      {
        "name": "TOWER HEALTH OBLIGATED GROUP 5.0% 06-30-39",
        "value": "18315498.74",
        "weight": "0.00264916",
        "shared": false
      },
      {
        "name": "MAIN STR NAT GA 5% MT",
        "value": "18310997.25",
        "weight": "0.00264851",
        "shared": false
      },
      {
        "name": "SPOKANE CNTY WA ARPT REVENUE",
        "value": "18295917.76",
        "weight": "0.00264633",
        "shared": false
      },
      {
        "name": "BLACK BELT ENERGY GAS VAR",
        "value": "18134798.50",
        "weight": "0.00262303",
        "shared": false
      },
      {
        "name": "CHICAGO ILLIN 6% 4/1/2046",
        "value": "17999717.26",
        "weight": "0.00260349",
        "shared": false
      },
      {
        "name": "California (State of) Housing Finance Agency (Social Certificates), Series 2023-1, RB",
        "value": "17903581.23",
        "weight": "0.00258958",
        "shared": false
      },
      {
        "name": "Fishers Town Hall Building Corp., Series 2023 A, RB",
        "value": "17353109.79",
        "weight": "0.00250996",
        "shared": false
      },
      {
        "name": "MASSACHUSETTS ST DEV FIN AGY R REGD B/E 5.00000000",
        "value": "17214293.50",
        "weight": "0.00248988",
        "shared": false
      },
      {
        "name": "Maryland Department of Housing & Community Development, Series 2024 E",
        "value": "17179480.78",
        "weight": "0.00248485",
        "shared": true
      },
      {
        "name": "WISCONSIN ST HT 4% 4/1/2040",
        "value": "16827152.94",
        "weight": "0.00243389",
        "shared": false
      },
      {
        "name": "New Hampshire Business Finance Authority, Series 2024A",
        "value": "16753590.49",
        "weight": "0.00242325",
        "shared": false
      },
      {
        "name": "PENNSYLVANIA ST ECON DEV FING REGD B/E AMT 5.00000000",
        "value": "16680576.77",
        "weight": "0.00241269",
        "shared": false
      },
      {
        "name": "Public Energy Authority of Kentucky, Gas Supply Revenue Bonds, Series 2025B",
        "value": "16505537.96",
        "weight": "0.00238737",
        "shared": true
      },
      {
        "name": "COLORADO ST HLTH FACS AUTH REV REGD B/E 4.00000000",
        "value": "16297175.41",
        "weight": "0.00235723",
        "shared": false
      },
      {
        "name": "ORANGE HLTH FACS-A",
        "value": "15910063.75",
        "weight": "0.00230124",
        "shared": false
      },
      {
        "name": "Jefferson (County of), AL, Series 2024, Ref. Revenue Wts.",
        "value": "15783655.47",
        "weight": "0.00228295",
        "shared": false
      },
      {
        "name": "SAN ANTONIO WTR 5.25% 5/15/2052",
        "value": "15584064.00",
        "weight": "0.00225409",
        "shared": false
      },
      {
        "name": "Travis County Healthcare District",
        "value": "15503484.00",
        "weight": "0.00224243",
        "shared": false
      },
      {
        "name": "Energy Southeast A Cooperative District, Series B-1",
        "value": "15438008.00",
        "weight": "0.00223296",
        "shared": false
      },
      {
        "name": "MICHIGAN ST HSG DEV AUTH RENTAL HSG REVENUE",
        "value": "15431357.06",
        "weight": "0.00223200",
        "shared": false
      },
      {
        "name": "FRETE ML-15 TRUST",
        "value": "15402544.35",
        "weight": "0.00222783",
        "shared": false
      },
      {
        "name": "California Community Choice Financing Authority, Series C",
        "value": "15398843.24",
        "weight": "0.00222730",
        "shared": false
      },
      {
        "name": "NY NYCDEV 5 11/15/2044",
        "value": "15300419.22",
        "weight": "0.00221306",
        "shared": true
      }
    ]
  },
  "error": null,
  "sources": [
    {
      "label": "N-PORT (fund A)",
      "accession_no": "0002071691-26-011429",
      "as_of": "2026-03-31",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/751656/000207169126011429/0002071691-26-011429-index.htm"
    },
    {
      "label": "N-PORT (fund B)",
      "accession_no": "0002071691-26-011438",
      "as_of": "2026-03-31",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/751656/000207169126011438/0002071691-26-011438-index.htm"
    }
  ]
}