{"license":"https://creativecommons.org/licenses/by/4.0/","dataset":"industry-history","count":4,"years":[2017,2022],"metric":"hhi","sources":[{"id":"census-ecnsize-concentration-2017","title":"2017 Economic Census Concentration of Largest Firms","publisher":"U.S. Census Bureau","citationAuthor":"U.S. Census Bureau","citationAuthorType":"organization","citationYear":2020,"url":"https://www2.census.gov/programs-surveys/economic-census/data/2017/sector00/EC1700SIZECONCEN.zip","description":"Economy-wide national firm concentration statistics by 2017 NAICS industry including revenue-based HHI and largest-firm concentration ratios.","sourceType":"public_dataset","accessDate":"2026-07-18","citationText":"U.S. Census Bureau, 2017 Economic Census, EC1700SIZECONCEN: Selected Sectors - Concentration of Largest Firms for the United States, released November 2020.","licenseNote":"Public federal government dataset","archivedUrl":null,"profileHref":"/sources/census-ecnsize-concentration-2017"},{"id":"census-ecnsize-concentration-2022","title":"2022 Economic Census Concentration of Largest Firms","publisher":"U.S. Census Bureau","citationAuthor":"U.S. Census Bureau","citationAuthorType":"organization","citationYear":2025,"url":"https://www2.census.gov/programs-surveys/economic-census/data/2022/sector00/EC2200SIZECONCEN.zip","description":"Economy-wide national firm concentration statistics by 2022 NAICS industry including revenue-based HHI and largest-firm concentration ratios.","sourceType":"public_dataset","accessDate":"2026-07-17","citationText":"U.S. Census Bureau, 2022 Economic Census, EC2200SIZECONCEN: Selected Sectors - Concentration of Largest Firms for the United States, released April 2025.","licenseNote":"Public federal government dataset","archivedUrl":null,"profileHref":"/sources/census-ecnsize-concentration-2022"}],"guardrail":"Five-year deltas are published only for rows whose NAICS code and industry label are identical in the 2017 and 2022 Census tables. This strict match is a conservative screening rule, not an official NAICS concordance or evidence of causation. Revenue changes are nominal and are not adjusted for inflation.","compositionGuardrail":null,"compositionSummary":null,"hhiDistributionGuardrail":"The benchmark contains strict six-digit NAICS matches with HHI published in both 2017 and 2022. Revenue and employment views hold each row's 2022 scale fixed, so band-share changes isolate HHI-band migration within this published pair universe. These distributions are not whole-economy concentration indexes, legal antitrust markets, liability findings, or causal estimates.","hhiDistributionSummary":{"benchmarkCount":789,"pairedCount":543,"coveragePercent":68.8,"medianHhi2017":265.5,"medianHhi2022":271.3,"medianHhiChange":3.6,"upwardBandCount":35,"downwardBandCount":27,"sameBandCount":481,"bands":[{"id":"under-500","label":"0-499","count2017":383,"count2022":383,"share2017Pct":70.534,"share2022Pct":70.534,"sharePointChange":0},{"id":"500-999","label":"500-999","count2017":106,"count2022":100,"share2017Pct":19.521,"share2022Pct":18.416,"sharePointChange":-1.105},{"id":"1000-1499","label":"1,000-1,499","count2017":37,"count2022":41,"share2017Pct":6.814,"share2022Pct":7.551,"sharePointChange":0.737},{"id":"1500-2499","label":"1,500-2,499","count2017":13,"count2022":14,"share2017Pct":2.394,"share2022Pct":2.578,"sharePointChange":0.184},{"id":"2500-plus","label":"2,500+","count2017":4,"count2022":5,"share2017Pct":0.737,"share2022Pct":0.921,"sharePointChange":0.184}]},"summary":{"currentCount":1866,"historicalCount":1935,"matchedCodeCount":1680,"strictMatchCount":1640,"classificationChangedCount":40,"new2022Count":186,"historicalOnlyCount":255,"currentDetailedCount":899,"historicalDetailedCount":943,"strictDetailedCount":789,"benchmarkCount":789,"pairedCount":543,"unavailableCount":246,"increasedCount":306,"decreasedCount":237,"unchangedCount":0,"medianChange":3.6},"filters":{"naics":null,"naicsMatched":null,"codes":["335931","311813","212312","326291"],"codesMatched":true,"matchedCodes":["335931","311813","212312","326291"],"unmatchedCodes":[],"branch":null,"branchMatched":null,"query":null,"level":6,"levelMatched":true,"sector":null,"sectorMatched":null,"metric":"hhi","metricMatched":true,"status":"strict_match","statusMatched":true,"availability":"all","availabilityMatched":true,"direction":"all","directionMatched":true,"hhiFromBand":null,"hhiFromBandMatched":true,"hhiToBand":null,"hhiToBandMatched":true,"sort":"change","sortMatched":true,"order":"desc","orderMatched":true},"rows":[{"naicsCode":"212312","industryLevel":6,"sectorCode":"21","sectorName":"Mining, quarrying, and oil and gas extraction","industryName2022":"Crushed and broken limestone mining and quarrying","industryName2017":"Crushed and broken limestone mining and quarrying","comparisonStatus":"strict_match","fromYear":2017,"toYear":2022,"metric":"hhi","fromValue":277.1,"toValue":287.1,"absoluteChange":10,"percentChange":3.6,"direction":"increased","hhi2017":277.1,"hhi2022":287.1,"hhiChange":10,"hhiBand2017":"under-500","hhiBand2022":"under-500","hhiBandMovement":"same","cr4Pct2017":28.7,"cr4Pct2022":28.6,"cr4PointChange":-0.1,"cr8Pct2017":40.1,"cr8Pct2022":38.5,"cr8PointChange":-1.6,"revenueThousands2017":8988284,"revenueThousands2022":10585207,"nominalRevenueChangeThousands":1596923,"employees2017":28665,"employees2022":25005,"employeeChange":-3660,"firms2017":566,"firms2022":483,"firmChange":-83,"sourceId2017":"census-ecnsize-concentration-2017","sourceId2022":"census-ecnsize-concentration-2022","profileHref":"/industries/212312"},{"naicsCode":"335931","industryLevel":6,"sectorCode":"31","sectorName":"Manufacturing","industryName2022":"Current-carrying wiring device manufacturing","industryName2017":"Current-carrying wiring device manufacturing","comparisonStatus":"strict_match","fromYear":2017,"toYear":2022,"metric":"hhi","fromValue":308.5,"toValue":313,"absoluteChange":4.5,"percentChange":1.5,"direction":"increased","hhi2017":308.5,"hhi2022":313,"hhiChange":4.5,"hhiBand2017":"under-500","hhiBand2022":"under-500","hhiBandMovement":"same","cr4Pct2017":26.4,"cr4Pct2022":27.5,"cr4PointChange":1.1,"cr8Pct2017":40.2,"cr8Pct2022":38.8,"cr8PointChange":-1.4,"revenueThousands2017":8281803,"revenueThousands2022":8376690,"nominalRevenueChangeThousands":94887,"employees2017":25404,"employees2022":24954,"employeeChange":-450,"firms2017":354,"firms2022":359,"firmChange":5,"sourceId2017":"census-ecnsize-concentration-2017","sourceId2022":"census-ecnsize-concentration-2022","profileHref":"/industries/335931"},{"naicsCode":"311813","industryLevel":6,"sectorCode":"31","sectorName":"Manufacturing","industryName2022":"Frozen cakes, pies, and other pastries manufacturing","industryName2017":"Frozen cakes, pies, and other pastries manufacturing","comparisonStatus":"strict_match","fromYear":2017,"toYear":2022,"metric":"hhi","fromValue":358.4,"toValue":301.5,"absoluteChange":-56.9,"percentChange":-15.9,"direction":"decreased","hhi2017":358.4,"hhi2022":301.5,"hhiChange":-56.9,"hhiBand2017":"under-500","hhiBand2022":"under-500","hhiBandMovement":"same","cr4Pct2017":32.1,"cr4Pct2022":25.6,"cr4PointChange":-6.5,"cr8Pct2017":43.2,"cr8Pct2022":39.1,"cr8PointChange":-4.1,"revenueThousands2017":6196603,"revenueThousands2022":8165134,"nominalRevenueChangeThousands":1968531,"employees2017":23557,"employees2022":25223,"employeeChange":1666,"firms2017":195,"firms2022":214,"firmChange":19,"sourceId2017":"census-ecnsize-concentration-2017","sourceId2022":"census-ecnsize-concentration-2022","profileHref":"/industries/311813"},{"naicsCode":"326291","industryLevel":6,"sectorCode":"31","sectorName":"Manufacturing","industryName2022":"Rubber product manufacturing for mechanical use","industryName2017":"Rubber product manufacturing for mechanical use","comparisonStatus":"strict_match","fromYear":2017,"toYear":2022,"metric":"hhi","fromValue":462.5,"toValue":333.6,"absoluteChange":-128.9,"percentChange":-27.9,"direction":"decreased","hhi2017":462.5,"hhi2022":333.6,"hhiChange":-128.9,"hhiBand2017":"under-500","hhiBand2022":"under-500","hhiBandMovement":"same","cr4Pct2017":32.9,"cr4Pct2022":29.5,"cr4PointChange":-3.4,"cr8Pct2017":48.4,"cr8Pct2022":45.5,"cr8PointChange":-2.9,"revenueThousands2017":7870081,"revenueThousands2022":7708825,"nominalRevenueChangeThousands":-161256,"employees2017":30606,"employees2022":29451,"employeeChange":-1155,"firms2017":344,"firms2022":328,"firmChange":-16,"sourceId2017":"census-ecnsize-concentration-2017","sourceId2022":"census-ecnsize-concentration-2022","profileHref":"/industries/326291"}]}