{
  "page": "compare",
  "query": {
    "a": "FZIPX",
    "b": "FSMAX"
  },
  "retrieved_at": "2026-07-07T17:05:48+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": "Fidelity ZERO Extended Market Index Fund",
    "ticker": "FZIPX",
    "slug": "FZIPX",
    "series_id": "S000063103",
    "html_url": "https://fundwatcher.app/funds/FZIPX/"
  },
  "fund_b": {
    "name": "Fidelity Extended Market Index Fund",
    "ticker": "FSMAX",
    "slug": "FSMAX",
    "series_id": "S000006021",
    "html_url": "https://fundwatcher.app/funds/FSMAX/"
  },
  "overlap": {
    "coverage_a_by_b": "0.7852642009398973651492037908",
    "coverage_b_by_a": "0.7852642009398973651492037907",
    "shared_count": 1940,
    "as_of": {
      "a": "2026-01-31",
      "b": "2026-02-28"
    },
    "a_top": [
      {
        "name": "Fidelity Securities Lending Cash Central Fund",
        "value": "93364198.34",
        "weight": "0.04104207",
        "shared": true
      },
      {
        "name": "SANDISK CORPORATION",
        "value": "24875560.00",
        "weight": "0.01093508",
        "shared": false
      },
      {
        "name": "COMFORT SYSTEMS USA INC",
        "value": "12466021.50",
        "weight": "0.00547995",
        "shared": false
      },
      {
        "name": "ANGLOGOLD ASHANTI PLC",
        "value": "12211940.65",
        "weight": "0.00536826",
        "shared": false
      },
      {
        "name": "ROCKET LAB CORP",
        "value": "11670923.13",
        "weight": "0.00513043",
        "shared": true
      },
      {
        "name": "CIENA CORP",
        "value": "11014673.02",
        "weight": "0.00484195",
        "shared": false
      },
      {
        "name": "COHERENT CORP",
        "value": "10340167.94",
        "weight": "0.00454545",
        "shared": true
      },
      {
        "name": "BLOOM ENERGY CORP CL A",
        "value": "10213539.38",
        "weight": "0.00448978",
        "shared": true
      },
      {
        "name": "EMCOR GROUP INC",
        "value": "10003011.67",
        "weight": "0.00439724",
        "shared": false
      },
      {
        "name": "SOFI TECHNOLOGIES INC A",
        "value": "8915744.70",
        "weight": "0.00391928",
        "shared": true
      },
      {
        "name": "FTAI AVIATION LTD",
        "value": "8659503.68",
        "weight": "0.00380664",
        "shared": true
      },
      {
        "name": "LUMENTUM HOLDINGS INC",
        "value": "8614994.24",
        "weight": "0.00378707",
        "shared": true
      },
      {
        "name": "AST SPACEMOBILE INC",
        "value": "8329962.63",
        "weight": "0.00366178",
        "shared": true
      },
      {
        "name": "TAPESTRY INC",
        "value": "8048378.38",
        "weight": "0.00353800",
        "shared": false
      },
      {
        "name": "CURTISS WRIGHT CORPORATION",
        "value": "7510563.53",
        "weight": "0.00330158",
        "shared": true
      },
      {
        "name": "FLEX LTD",
        "value": "7227536.00",
        "weight": "0.00317716",
        "shared": true
      },
      {
        "name": "CH ROBINSON WORLDWIDE INC",
        "value": "7141993.25",
        "weight": "0.00313956",
        "shared": false
      },
      {
        "name": "REDDIT INC-A",
        "value": "7088036.13",
        "weight": "0.00311584",
        "shared": true
      },
      {
        "name": "CASEY'S GENERAL",
        "value": "6991125.50",
        "weight": "0.00307324",
        "shared": true
      },
      {
        "name": "TECHNIPFMC PLC",
        "value": "6983443.32",
        "weight": "0.00306986",
        "shared": true
      },
      {
        "name": "PURE STORAGE INC CL A",
        "value": "6733558.20",
        "weight": "0.00296001",
        "shared": true
      },
      {
        "name": "ROYAL GOLD INC",
        "value": "6618560.16",
        "weight": "0.00290946",
        "shared": true
      },
      {
        "name": "UNITED THERAPEUTICS CORP DEL",
        "value": "6266283.03",
        "weight": "0.00275460",
        "shared": true
      },
      {
        "name": "ALBEMARLE CORP",
        "value": "6228506.89",
        "weight": "0.00273800",
        "shared": false
      },
      {
        "name": "EXACT SCIENCES CORP",
        "value": "6011144.58",
        "weight": "0.00264245",
        "shared": true
      },
      {
        "name": "CREDO TECHNOLOGY GROUP HOLDING LTD",
        "value": "5914969.92",
        "weight": "0.00260017",
        "shared": true
      },
      {
        "name": "WOODWARD INC",
        "value": "5908963.44",
        "weight": "0.00259753",
        "shared": true
      },
      {
        "name": "BWX TECHNOLOGIES INC",
        "value": "5825789.37",
        "weight": "0.00256097",
        "shared": true
      },
      {
        "name": "US FOODS HOLDING CORP",
        "value": "5774880.82",
        "weight": "0.00253859",
        "shared": true
      },
      {
        "name": "ROLLINS INC",
        "value": "5756339.20",
        "weight": "0.00253044",
        "shared": false
      },
      {
        "name": "TEMPUR SEALY INTERNATIONAL INC",
        "value": "5713939.70",
        "weight": "0.00251180",
        "shared": true
      },
      {
        "name": "NVENT ELECTRIC PLC",
        "value": "5616704.58",
        "weight": "0.00246905",
        "shared": true
      },
      {
        "name": "Fidelity Cash Central Fund",
        "value": "5613344.97",
        "weight": "0.00246758",
        "shared": true
      },
      {
        "name": "LOEWS CORP",
        "value": "5520149.73",
        "weight": "0.00242661",
        "shared": false
      },
      {
        "name": "REVOLUTION MEDICINES INC",
        "value": "5462066.05",
        "weight": "0.00240108",
        "shared": true
      },
      {
        "name": "FABRINET",
        "value": "5441104.48",
        "weight": "0.00239186",
        "shared": true
      },
      {
        "name": "AFFIRM HOLDINGS INC",
        "value": "5411804.40",
        "weight": "0.00237898",
        "shared": true
      },
      {
        "name": "KRATOS DEFENSE and SEC SOLTN INC",
        "value": "5394736.71",
        "weight": "0.00237148",
        "shared": true
      },
      {
        "name": "NEXTRACKER INC CL A",
        "value": "5389769.79",
        "weight": "0.00236929",
        "shared": true
      },
      {
        "name": "XPO LOGISTICS INC",
        "value": "5389278.57",
        "weight": "0.00236908",
        "shared": true
      },
      {
        "name": "ROCKET COS INC-A",
        "value": "5377601.46",
        "weight": "0.00236395",
        "shared": true
      },
      {
        "name": "PENTAIR PLC",
        "value": "5338781.79",
        "weight": "0.00234688",
        "shared": false
      },
      {
        "name": "JONES LANG LASALLE INC",
        "value": "5237297.03",
        "weight": "0.00230227",
        "shared": true
      },
      {
        "name": "TENET HEALTHCARE CORP",
        "value": "5157501.44",
        "weight": "0.00226719",
        "shared": true
      },
      {
        "name": "HUNTINGTON INGALLS INDUSTRIES INC",
        "value": "5118868.23",
        "weight": "0.00225021",
        "shared": false
      },
      {
        "name": "INCYTE CORP",
        "value": "5115178.12",
        "weight": "0.00224859",
        "shared": false
      },
      {
        "name": "ATI INC",
        "value": "5068359.30",
        "weight": "0.00222801",
        "shared": true
      },
      {
        "name": "TALEN ENERGY CORP",
        "value": "4936609.56",
        "weight": "0.00217009",
        "shared": true
      },
      {
        "name": "CARPENTER TECHNOLOGY CORP",
        "value": "4910155.67",
        "weight": "0.00215846",
        "shared": true
      },
      {
        "name": "MKS INSTRUMENTS INC",
        "value": "4897234.23",
        "weight": "0.00215278",
        "shared": true
      }
    ],
    "b_top": [
      {
        "name": "Fidelity Securities Lending Cash Central Fund",
        "value": "2265848955.41",
        "weight": "0.05245502",
        "shared": true
      },
      {
        "name": "VERTIV HOLDINGS CO",
        "value": "510291564.23",
        "weight": "0.01181339",
        "shared": false
      },
      {
        "name": "MARVELL TECHNOLOGY INC",
        "value": "368750783.94",
        "weight": "0.00853668",
        "shared": false
      },
      {
        "name": "SNOWFLAKE INC CL A",
        "value": "299488386.89",
        "weight": "0.00693324",
        "shared": false
      },
      {
        "name": "CLOUDFLARE INC-A",
        "value": "284650904.99",
        "weight": "0.00658975",
        "shared": false
      },
      {
        "name": "FERGUSON ENTERPRISES INC",
        "value": "267516030.84",
        "weight": "0.00619307",
        "shared": false
      },
      {
        "name": "CHENIERE ENERGY INC",
        "value": "265342166.87",
        "weight": "0.00614274",
        "shared": false
      },
      {
        "name": "LUMENTUM HOLDINGS INC",
        "value": "260235967.53",
        "weight": "0.00602453",
        "shared": true
      },
      {
        "name": "ROBLOX CORP - A",
        "value": "235197782.38",
        "weight": "0.00544489",
        "shared": false
      },
      {
        "name": "ALNYLAM PHARMACEUTICALS INC",
        "value": "230301737.96",
        "weight": "0.00533155",
        "shared": false
      },
      {
        "name": "COHERENT CORP",
        "value": "213083595.27",
        "weight": "0.00493294",
        "shared": true
      },
      {
        "name": "STRATEGY INC CL A",
        "value": "182114555.00",
        "weight": "0.00421600",
        "shared": false
      },
      {
        "name": "BLOOM ENERGY CORP CL A",
        "value": "177548640.15",
        "weight": "0.00411030",
        "shared": true
      },
      {
        "name": "AMRIZE LTD",
        "value": "175030938.02",
        "weight": "0.00405201",
        "shared": false
      },
      {
        "name": "ROCKET LAB CORP",
        "value": "170374480.20",
        "weight": "0.00394422",
        "shared": true
      },
      {
        "name": "INSMED INC",
        "value": "166853576.84",
        "weight": "0.00386271",
        "shared": false
      },
      {
        "name": "FTAI AVIATION LTD",
        "value": "164161085.00",
        "weight": "0.00380037",
        "shared": true
      },
      {
        "name": "NATERA INC",
        "value": "150346347.20",
        "weight": "0.00348056",
        "shared": false
      },
      {
        "name": "VEEVA SYSTEMS-A",
        "value": "145491331.59",
        "weight": "0.00336816",
        "shared": false
      },
      {
        "name": "MONGODB INC CL A",
        "value": "139901613.93",
        "weight": "0.00323876",
        "shared": false
      },
      {
        "name": "TECHNIPFMC PLC",
        "value": "139684004.30",
        "weight": "0.00323372",
        "shared": true
      },
      {
        "name": "MARKEL GROUP INC",
        "value": "136264902.50",
        "weight": "0.00315457",
        "shared": false
      },
      {
        "name": "COUPANG INC A",
        "value": "134922464.64",
        "weight": "0.00312349",
        "shared": false
      },
      {
        "name": "CURTISS WRIGHT CORPORATION",
        "value": "134889860.97",
        "weight": "0.00312274",
        "shared": true
      },
      {
        "name": "CASEY'S GENERAL",
        "value": "133295835.75",
        "weight": "0.00308583",
        "shared": true
      },
      {
        "name": "XPO LOGISTICS INC",
        "value": "129169858.87",
        "weight": "0.00299032",
        "shared": true
      },
      {
        "name": "ROYAL GOLD INC",
        "value": "127130746.14",
        "weight": "0.00294311",
        "shared": true
      },
      {
        "name": "LPL FINL HLDGS INC",
        "value": "125715337.98",
        "weight": "0.00291034",
        "shared": false
      },
      {
        "name": "FLEX LTD",
        "value": "121993422.78",
        "weight": "0.00282418",
        "shared": true
      },
      {
        "name": "WOODWARD INC",
        "value": "121212131.04",
        "weight": "0.00280609",
        "shared": true
      },
      {
        "name": "SOFI TECHNOLOGIES INC A",
        "value": "117609028.80",
        "weight": "0.00272268",
        "shared": true
      },
      {
        "name": "ATI INC",
        "value": "116221043.19",
        "weight": "0.00269055",
        "shared": true
      },
      {
        "name": "UNITED THERAPEUTICS CORP DEL",
        "value": "113473241.00",
        "weight": "0.00262694",
        "shared": true
      },
      {
        "name": "US FOODS HOLDING CORP",
        "value": "112653829.48",
        "weight": "0.00260797",
        "shared": true
      },
      {
        "name": "TENET HEALTHCARE CORP",
        "value": "110170390.07",
        "weight": "0.00255047",
        "shared": true
      },
      {
        "name": "ILLUMINA INC",
        "value": "107474550.30",
        "weight": "0.00248806",
        "shared": false
      },
      {
        "name": "LIBERTY MEDIA CORP LIBERTY FORMULA ONE CL C",
        "value": "106898169.42",
        "weight": "0.00247472",
        "shared": false
      },
      {
        "name": "ENTEGRIS INC",
        "value": "105151260.30",
        "weight": "0.00243428",
        "shared": false
      },
      {
        "name": "PURE STORAGE INC CL A",
        "value": "105017745.82",
        "weight": "0.00243119",
        "shared": true
      },
      {
        "name": "CARPENTER TECHNOLOGY CORP",
        "value": "103811879.16",
        "weight": "0.00240327",
        "shared": true
      },
      {
        "name": "EXACT SCIENCES CORP",
        "value": "102492275.94",
        "weight": "0.00237272",
        "shared": true
      },
      {
        "name": "FABRINET",
        "value": "102414751.00",
        "weight": "0.00237093",
        "shared": true
      },
      {
        "name": "AST SPACEMOBILE INC",
        "value": "100036371.55",
        "weight": "0.00231587",
        "shared": true
      },
      {
        "name": "FIRST CITIZENS BANCSHARES INC CL A",
        "value": "99992643.85",
        "weight": "0.00231486",
        "shared": false
      },
      {
        "name": "BURLINGTON STORES INC",
        "value": "99913803.30",
        "weight": "0.00231303",
        "shared": false
      },
      {
        "name": "NVENT ELECTRIC PLC",
        "value": "99850981.56",
        "weight": "0.00231158",
        "shared": true
      },
      {
        "name": "BWX TECHNOLOGIES INC",
        "value": "98482951.62",
        "weight": "0.00227991",
        "shared": true
      },
      {
        "name": "TEMPUR SEALY INTERNATIONAL INC",
        "value": "98223619.48",
        "weight": "0.00227390",
        "shared": true
      },
      {
        "name": "RB GLOBAL INC",
        "value": "97919589.60",
        "weight": "0.00226687",
        "shared": false
      },
      {
        "name": "HEICO CORP CL A",
        "value": "97854189.29",
        "weight": "0.00226535",
        "shared": false
      }
    ]
  },
  "error": null,
  "sources": [
    {
      "label": "N-PORT (fund A)",
      "accession_no": "0000035402-26-002124",
      "as_of": "2026-01-31",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/819118/000003540226002124/0000035402-26-002124-index.htm"
    },
    {
      "label": "N-PORT (fund B)",
      "accession_no": "0000035402-26-002587",
      "as_of": "2026-02-28",
      "edgar_url": "https://www.sec.gov/Archives/edgar/data/819118/000003540226002587/0000035402-26-002587-index.htm"
    }
  ]
}