{
  "page": "compare",
  "query": {
    "a": "MFGSX",
    "b": "BFIX"
  },
  "retrieved_at": "2026-07-07T19:07:41+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 Government Securities Fund",
    "ticker": "MFGSX",
    "slug": "MFGSX",
    "series_id": "S000000693",
    "html_url": "https://fundwatcher.app/funds/MFGSX/"
  },
  "fund_b": {
    "name": "Build Bond Innovation ETF",
    "ticker": "BFIX",
    "slug": "BFIX",
    "series_id": "S000074231",
    "html_url": "https://fundwatcher.app/funds/BFIX/"
  },
  "overlap": {
    "coverage_a_by_b": "0.08970742495448227720521402831",
    "coverage_b_by_a": "0.08970742495448227720521402831",
    "shared_count": 3,
    "as_of": {
      "a": "2026-02-28",
      "b": "2026-03-31"
    },
    "a_top": [
      {
        "name": "US TREASURY N/B",
        "value": "89897417.88",
        "weight": "0.04303978",
        "shared": true
      },
      {
        "name": "US TREASURY N/B",
        "value": "86751392.79",
        "weight": "0.04153357",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "78445763.59",
        "weight": "0.03755712",
        "shared": true
      },
      {
        "name": "US TREASURY N/B",
        "value": "71917991.51",
        "weight": "0.03443185",
        "shared": false
      },
      {
        "name": "MFS Institutional Money Market Portfolio, Class A",
        "value": "66107888.58",
        "weight": "0.03165018",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "53509654.88",
        "weight": "0.02561858",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "38610233.88",
        "weight": "0.01848525",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "38019006.74",
        "weight": "0.01820219",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "37444275.00",
        "weight": "0.01792703",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "35011737.03",
        "weight": "0.01676241",
        "shared": false
      },
      {
        "name": "FNCL 2 4/26",
        "value": "32907795.53",
        "weight": "0.01575512",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "30483177.89",
        "weight": "0.01459429",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "28074375.00",
        "weight": "0.01344104",
        "shared": false
      },
      {
        "name": "FHMS K057 A2",
        "value": "25399154.30",
        "weight": "0.01216024",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "22075250.63",
        "weight": "0.01056887",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "21055831.88",
        "weight": "0.01008081",
        "shared": true
      },
      {
        "name": "FN MA4562",
        "value": "20833726.03",
        "weight": "0.00997447",
        "shared": false
      },
      {
        "name": "FHMS K066 A2",
        "value": "20454857.15",
        "weight": "0.00979308",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "18907927.65",
        "weight": "0.00905246",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "18691048.92",
        "weight": "0.00894863",
        "shared": false
      },
      {
        "name": "G2 MA8268",
        "value": "16977102.67",
        "weight": "0.00812805",
        "shared": false
      },
      {
        "name": "Uniform Mortgage-Backed Security, TBA",
        "value": "16937381.62",
        "weight": "0.00810903",
        "shared": false
      },
      {
        "name": "FHMS K062 A2",
        "value": "16470120.08",
        "weight": "0.00788533",
        "shared": false
      },
      {
        "name": "Federal Home Loan Mortgage Corporation",
        "value": "13288654.99",
        "weight": "0.00636215",
        "shared": false
      },
      {
        "name": "FR SD8507",
        "value": "12536793.09",
        "weight": "0.00600218",
        "shared": false
      },
      {
        "name": "UMBS",
        "value": "11894046.07",
        "weight": "0.00569446",
        "shared": false
      },
      {
        "name": "FHMS K059 A2",
        "value": "11875704.58",
        "weight": "0.00568568",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "11690405.58",
        "weight": "0.00559696",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "11495187.56",
        "weight": "0.00550350",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "11140201.93",
        "weight": "0.00533354",
        "shared": false
      },
      {
        "name": "GNMA, Series 2023-135, Class FG",
        "value": "10750626.78",
        "weight": "0.00514703",
        "shared": false
      },
      {
        "name": "FHMS K737 A2",
        "value": "10734453.62",
        "weight": "0.00513929",
        "shared": false
      },
      {
        "name": "GNMA, Series 2023-189, Class FG",
        "value": "10539187.92",
        "weight": "0.00504580",
        "shared": false
      },
      {
        "name": "GNMA, Series 2023-149, Class YF",
        "value": "10461239.15",
        "weight": "0.00500848",
        "shared": false
      },
      {
        "name": "Government National Mortgage Association",
        "value": "10434106.16",
        "weight": "0.00499549",
        "shared": false
      },
      {
        "name": "GNMA, Series 2023-146, Class FD",
        "value": "10361255.46",
        "weight": "0.00496061",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "10114960.91",
        "weight": "0.00484269",
        "shared": false
      },
      {
        "name": "New Residential Mortgage Loan Trust, Series 2026-NQM3, Class A1",
        "value": "10084506.84",
        "weight": "0.00482811",
        "shared": false
      },
      {
        "name": "PMT Loan Trust, Series 2026-INV2, Class A35",
        "value": "10048507.04",
        "weight": "0.00481088",
        "shared": false
      },
      {
        "name": "FHMS K065 A2",
        "value": "10027344.72",
        "weight": "0.00480075",
        "shared": false
      },
      {
        "name": "LoanCore Issuer Ltd., Series 2021-CRE6, Class AS",
        "value": "10005940.00",
        "weight": "0.00479050",
        "shared": false
      },
      {
        "name": "UMBS",
        "value": "9991148.23",
        "weight": "0.00478342",
        "shared": false
      },
      {
        "name": "G2 MA7935",
        "value": "9671285.77",
        "weight": "0.00463028",
        "shared": false
      },
      {
        "name": "GNMA, Series 2025-177, Class FA",
        "value": "9666301.78",
        "weight": "0.00462789",
        "shared": false
      },
      {
        "name": "Government National Mortgage Association",
        "value": "9642944.89",
        "weight": "0.00461671",
        "shared": false
      },
      {
        "name": "G2 MA7880",
        "value": "9564613.12",
        "weight": "0.00457921",
        "shared": false
      },
      {
        "name": "FN MA5353",
        "value": "9509870.03",
        "weight": "0.00455300",
        "shared": false
      },
      {
        "name": "Government National Mortgage Association",
        "value": "9489523.06",
        "weight": "0.00454326",
        "shared": false
      },
      {
        "name": "Government National Mortgage Association",
        "value": "9418293.22",
        "weight": "0.00450915",
        "shared": false
      },
      {
        "name": "American Credit Acceptance Receivables Trust, Series 2026-1, Class A",
        "value": "9100074.62",
        "weight": "0.00435680",
        "shared": false
      }
    ],
    "b_top": [
      {
        "name": "US TREASURY N/B",
        "value": "912740.63",
        "weight": "0.07280128",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "664137.50",
        "weight": "0.05297240",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "656519.53",
        "weight": "0.05236478",
        "shared": true
      },
      {
        "name": "US TREASURY N/B",
        "value": "650495.12",
        "weight": "0.05188427",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "649542.97",
        "weight": "0.05180832",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "527443.16",
        "weight": "0.04206950",
        "shared": true
      },
      {
        "name": "US TREASURY N/B",
        "value": "521762.82",
        "weight": "0.04161642",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "499335.94",
        "weight": "0.03982763",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "486382.42",
        "weight": "0.03879444",
        "shared": true
      },
      {
        "name": "US TREASURY N/B",
        "value": "450210.94",
        "weight": "0.03590936",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "351115.51",
        "weight": "0.02800539",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "320386.06",
        "weight": "0.02555437",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "270898.31",
        "weight": "0.02160717",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "219962.64",
        "weight": "0.01754448",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "168558.98",
        "weight": "0.01344447",
        "shared": false
      },
      {
        "name": "ESSEX PORTFOLIO",
        "value": "155942.72",
        "weight": "0.01243818",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "150538.37",
        "weight": "0.01200712",
        "shared": false
      },
      {
        "name": "AUTOZONE INC",
        "value": "131924.41",
        "weight": "0.01052245",
        "shared": false
      },
      {
        "name": "US TREASURY N/B",
        "value": "130492.58",
        "weight": "0.01040824",
        "shared": false
      },
      {
        "name": "HUNT INGALLS IND",
        "value": "127647.68",
        "weight": "0.01018133",
        "shared": false
      },
      {
        "name": "ORACLE CORP",
        "value": "123326.70",
        "weight": "0.00983668",
        "shared": false
      },
      {
        "name": "AVALONBAY COMMUN",
        "value": "120835.86",
        "weight": "0.00963801",
        "shared": false
      },
      {
        "name": "INTERCONTINENT",
        "value": "120496.52",
        "weight": "0.00961095",
        "shared": false
      },
      {
        "name": "IBM CORP",
        "value": "119891.80",
        "weight": "0.00956271",
        "shared": false
      },
      {
        "name": "ESSEX PORTFOLIO",
        "value": "117970.13",
        "weight": "0.00940944",
        "shared": false
      },
      {
        "name": "LOWE'S COS INC",
        "value": "113650.05",
        "weight": "0.00906486",
        "shared": false
      },
      {
        "name": "GEORGIA POWER",
        "value": "108000.00",
        "weight": "0.00861421",
        "shared": false
      },
      {
        "name": "ANALOG DEVICES",
        "value": "101151.62",
        "weight": "0.00806797",
        "shared": false
      },
      {
        "name": "Clorox Co/The",
        "value": "97880.89",
        "weight": "0.00780710",
        "shared": false
      },
      {
        "name": "AT&T INC",
        "value": "94848.43",
        "weight": "0.00756522",
        "shared": false
      },
      {
        "name": "AUTODESK INC",
        "value": "88982.33",
        "weight": "0.00709734",
        "shared": false
      },
      {
        "name": "RADIAN GROUP INC",
        "value": "88929.97",
        "weight": "0.00709316",
        "shared": false
      },
      {
        "name": "TELEDYNE TECH",
        "value": "88000.00",
        "weight": "0.00701898",
        "shared": false
      },
      {
        "name": "TOYOTA MTR CRED",
        "value": "86057.79",
        "weight": "0.00686407",
        "shared": false
      },
      {
        "name": "ENERGY TRANSFER",
        "value": "84457.66",
        "weight": "0.00673644",
        "shared": false
      },
      {
        "name": "AMPHENOL CORP",
        "value": "82616.51",
        "weight": "0.00658959",
        "shared": false
      },
      {
        "name": "PHILLIPS 66 CO",
        "value": "79790.50",
        "weight": "0.00636419",
        "shared": false
      },
      {
        "name": "BERKSHIRE HATHAW",
        "value": "79496.89",
        "weight": "0.00634077",
        "shared": false
      },
      {
        "name": "MARRIOTT INTL",
        "value": "76808.96",
        "weight": "0.00612637",
        "shared": false
      },
      {
        "name": "TOYOTA MTR CRED",
        "value": "76244.94",
        "weight": "0.00608139",
        "shared": false
      },
      {
        "name": "KMI 7 1/2 11/15/26",
        "value": "72157.39",
        "weight": "0.00575536",
        "shared": false
      },
      {
        "name": "FRST AM-GV OB-X",
        "value": "71677.54",
        "weight": "0.00571709",
        "shared": false
      },
      {
        "name": "WASTE MANAGEMENT",
        "value": "70468.71",
        "weight": "0.00562067",
        "shared": false
      },
      {
        "name": "HERSHEY COMPANY",
        "value": "68481.14",
        "weight": "0.00546214",
        "shared": false
      },
      {
        "name": "NUCOR CORP",
        "value": "67087.32",
        "weight": "0.00535096",
        "shared": false
      },
      {
        "name": "WALMART INC",
        "value": "66972.40",
        "weight": "0.00534180",
        "shared": false
      },
      {
        "name": "US BANCORP",
        "value": "65949.67",
        "weight": "0.00526022",
        "shared": false
      },
      {
        "name": "ENTERPRISE PRODUCTS OPER REGD 4.15000000",
        "value": "63882.36",
        "weight": "0.00509533",
        "shared": false
      },
      {
        "name": "SCHLUMBERGER INV",
        "value": "62250.75",
        "weight": "0.00496519",
        "shared": false
      },
      {
        "name": "T-MOBILE USA INC",
        "value": "61955.02",
        "weight": "0.00494161",
        "shared": false
      }
    ]
  },
  "error": null,
  "sources": [
    {
      "label": "N-PORT (fund A)",
      "accession_no": "0002071691-26-008227",
      "as_of": "2026-02-28",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/356349/000207169126008227/0002071691-26-008227-index.htm"
    },
    {
      "label": "N-PORT (fund B)",
      "accession_no": "0000894189-26-016538",
      "as_of": "2026-03-31",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/1875710/000089418926016538/0000894189-26-016538-index.htm"
    }
  ]
}