Antitrust Radar
Competition Research BriefsAR-RB-2026-07

State Individual Insurance Concentration, 2024

Highly concentrated readings appear in 36 of 51 jurisdictions

By Antitrust Radar Research TeamResearch briefJul 24, 2026Version 1.0 · Current edition

Central finding

KFF's 2024 individual-insurance dataset reports a median HHI of 3,414 across the 50 states and District of Columbia.

This cross-section describes the source-defined 2024 ACA-regulated individual health insurance market using KFF state and District of Columbia measures. It does not measure employer-sponsored insurance, Medicare, Medicaid, every insurance product, a state's overall economy, competitive effects, or legal liability. HHI, leading-insurer share, and the count of insurers above 5 percent are structural screens; the public packet does not identify insurers or common control in each jurisdiction.

1
source
51
jurisdictions
36
high-HHI jurisdictions

Publication accountability

Recorded source access / review
. This is not an independent review date.
Authorship and responsibility
Antitrust Radar Research Team. Inspect individual roles and disclosure gaps.
Evidence overview

Jurisdiction evidence route

Follow the finding from state structure to source-defined market.

The route preserves all 51 KFF jurisdiction rows, three related structure measures, the 2024 product boundary, and a reproducible handoff.

Open JSON Run notebook

Declared analytical scope

ACA individual product to jurisdiction screen to KFF source custody

No insurer identity, common-control reconstruction, causal mechanism, outcome, or legal conclusion is asserted.

Read boundary
Sources, citations, and policy proposals

Public action docket

What government can require next

4 asks

ForHHS, CMS, FTC, DOJ, Congress, state insurance regulators, state attorneys general, and competition researchers

  1. 01
    Publish complete state insurer-share tables

    Release insurer identities, enrollment shares, common-control links, denominator rules, suppression flags, and reproducible HHI calculations for every jurisdiction under stable identifiers.

  2. 02
    Build a comparable annual market panel

    Publish annual state vintages with plan entry, exit, mergers, service areas, exchange participation, ownership changes, revisions, and product-definition changes kept explicit.

  3. 03
    Connect structure to public outcomes

    Link stable state, insurer, and plan identifiers to premiums, actuarial value, claims, denials, network breadth, quality, enrollment, switching, complaints, and geographic access.

Evidence still needed

State insurer identities, enrollment shares, and common controlStable plan, issuer, service-area, and jurisdiction identifiersAnnual entry, exit, merger, exchange, ownership, and revision histories
Open advocacy brief

Reader packet

Reusable

Canonical citation

Antitrust Radar Research Team. (2026, July 24). State Individual Insurance Concentration, 2024: Highly concentrated readings appear in 36 of 51 jurisdictions. Competition Research Briefs, AR-RB-2026-07 (Version 1.0). Antitrust Radar. https://antitrustradar.org/reports/state-individual-insurance-concentration-2024

JSONCSV
BibTeXRIS

Briefing packetcite, audit, actKFF state JSON51 exact jurisdiction rowsKFF state CSVHHI, leader share, rival depthExecutable notebook51 rows / 6 reconciliation checksKFF source dossiercustody, method, releaseState concentration atlasinteractive metric and state viewsIndividual insurance profilenational anchor and definitionAction briefpublic research asksMethodologylimits and caveats

Source basis

KFF 2024 Individual Insurance Market Competition data for the 50 states and District of Columbia, including source-reported HHI, leading-insurer share, and the count of insurers with more than 5 percent of each jurisdiction's ACA-regulated individual market.

1

Source record

51

Jurisdictions

1

public dataset

Source types

5

Evidence asks

Read the briefing

Evidence index

Claim to public action

Published Jul 24, 2026 · sources through Jun 23, 2026 · version 1.0 · Current edition

Read / Briefing claim

Start with the authored claim and its analytical boundary.

Start with the jurisdiction distribution, state map, related structure measures, and permanent product boundary.

Interpretation boundaryRead the finding with the report's declared market, geography, vintage, and limitations.
Read the analysis

National distribution

36 of 51 jurisdictions report HHI at or above 2,500.

The median jurisdiction HHI is 3,414; the separate national KFF anchor is 3,650.
High HHI
70.6%
36 jurisdictions
Majority leader
41.2%
21 jurisdictions
Thin rival depth
52.9%
27 jurisdictions

National distribution

One source-defined market, 51 separately reported jurisdiction screens

KFF / 2024

Jurisdiction HHI field

Five descriptive concentration bands

51 total rows
Below 1,5001

2% of jurisdictions

WI
1,500-2,49914

27.5% of jurisdictions

AZ · CA · CO · GA · ID · MI · MO · NY · OH · OR · PA · TX · VA · WA
2,500-3,99919

37.3% of jurisdictions

AL · FL · IL · IN · KS · KY · LA · MA · ME · MN · MS · MT · NC · NJ · NM · NV · OK · SD · TN
4,000-5,49910

19.6% of jurisdictions

AR · CT · HI · MD · ND · NE · RI · SC · UT · WV
5,500+7

13.7% of jurisdictions

AK · DC · DE · IA · NH · VT · WY

State concentration map

Inspect every jurisdiction and switch among all three KFF measures

Open state atlas

Geographic concentration

U.S. individual health insurance: market power by state

State-level ACA individual-market signals for 2024. Switch layers to compare concentration, leading-insurer share, and meaningful insurer depth.

U.S. average · HHI

3,650

Market HHI

View

Market HHI

Average 3,650 · Measures overall insurer concentration in each state.

Low · WI 1,474High · DC 6,945

Route dossier

District of Columbia route

District of Columbia is above the U.S. benchmark on HHI.

HighestDC · 6,945District of Columbia · Highly concentrated
LowestWI · 1,474Wisconsin · Unconcentrated
U.S. HHI 3,650above the U.S. benchmark

Selected state

District of Columbia

6,945

HHI

6,945

HHI

2

Insurers >5%

Highly concentrated

+3,295 vs. U.S. average.

State comparators

Selected packet

District of Columbia evidence packet

DC is above the U.S. benchmark on HHI; public JSON and CSV packets keep the state row reproducible.

DC
HHI6,945above the U.S. benchmark.
HHI class6,945Highly concentrated HHI classification.
Rival depth2Meaningful rivals above 5% share.

Priority review: high concentration, dominant-share, or thin-rival signals justify source-backed scrutiny.

/api/public/geography?state=DC
State profileJSONCSVConsoleSource

KFF · 2024

HHI scale

  • < 1,500
  • 1,500–2,499
  • 2,500–3,999
  • 4,000–5,499
  • 5,500+
  • No data

Regional pressure

Census regions ranked by HHI; insurer depth is inverted to surface fewer-rival regions first.

Cluster lens
Northeast4,037 avg

Peak NH 5,804 · 5/9 states above U.S. avg · 7 high HHI

South3,822 avg

Peak DC 6,945 · 8/17 states above U.S. avg · 14 high HHI

West3,523 avg

Peak AK 6,102 · 5/13 states above U.S. avg · 7 high HHI

Midwest3,252 avg

Peak IA 5,965 · 4/12 states above U.S. avg · 8 high HHI

KFF · Individual Insurance Market Competition (HHI by state) · 2024How HHI is read Browse state profiles

Regional comparison

Regional medians differ, but each region contains substantial internal variation

No regional score
Northeast3,864median HHI
Jurisdictions
9
Average HHI
4,037
At or above 2,500
7 77.8%
Majority leader
6
Thin rival depth
6
Midwest3,177median HHI
Jurisdictions
12
Average HHI
3,252
At or above 2,500
8 66.7%
Majority leader
4
Thin rival depth
6
South3,644median HHI
Jurisdictions
17
Average HHI
3,822
At or above 2,500
14 82.4%
Majority leader
7
Thin rival depth
10
West2,811median HHI
Jurisdictions
13
Average HHI
3,523
At or above 2,500
7 53.8%
Majority leader
4
Thin rival depth
5

Census regions organize the cross-section for description only. They are not insurance markets, causal controls, or substitutes for state-specific product and regulatory evidence.

Structure relationships

Higher HHI closely tracks leading-insurer share in this same-source cross-section

Pearson r = +0.959

HHI / leading-insurer share

Each point is one jurisdiction

Color = Census region
State individual-insurance HHI and leading-insurer share in 2024Fifty-one jurisdiction points show a positive descriptive relationship between HHI and leading-insurer share. Colors identify Census regions.1,5002,5004,0005,5007,00020%30%40%50%60%70%80%District of Columbia: HHI 6,945; leading share 81%; 2 insurers above 5%.DCAlaska: HHI 6,102; leading share 74%; 2 insurers above 5%.AKIowa: HHI 5,965; leading share 75%; 3 insurers above 5%.IADelaware: HHI 5,925; leading share 75%; 3 insurers above 5%.New Hampshire: HHI 5,804; leading share 73%; 3 insurers above 5%.Wyoming: HHI 5,695; leading share 69%; 2 insurers above 5%.Vermont: HHI 5,648; leading share 68%; 2 insurers above 5%.Rhode Island: HHI 5,433; leading share 65%; 2 insurers above 5%.Hawaii: HHI 5,385; leading share 64%; 2 insurers above 5%.Utah: HHI 5,304; leading share 70%; 3 insurers above 5%.West Virginia: HHI 5,025; leading share 57%; 2 insurers above 5%.Arkansas: HHI 4,983; leading share 53%; 2 insurers above 5%.Connecticut: HHI 4,975; leading share 54%; 2 insurers above 5%.North Dakota: HHI 4,878; leading share 59%; 2 insurers above 5%.Maryland: HHI 4,225; leading share 58%; 3 insurers above 5%.South Carolina: HHI 4,167; leading share 51%; 3 insurers above 5%.Nebraska: HHI 4,116; leading share 56%; 3 insurers above 5%.Alabama: HHI 3,963; leading share 47%; 3 insurers above 5%.Montana: HHI 3,955; leading share 49%; 3 insurers above 5%.Oklahoma: HHI 3,916; leading share 57%; 4 insurers above 5%.Massachusetts: HHI 3,864; leading share 56%; 4 insurers above 5%.Illinois: HHI 3,666; leading share 57%; 5 insurers above 5%.Kentucky: HHI 3,644; leading share 49%; 3 insurers above 5%.Minnesota: HHI 3,547; leading share 42%; 3 insurers above 5%.Louisiana: HHI 3,450; leading share 49%; 4 insurers above 5%.Maine: HHI 3,414; leading share 43%; 3 insurers above 5%.South Dakota: HHI 3,396; leading share 40%; 3 insurers above 5%.New Jersey: HHI 3,387; leading share 50%; 3 insurers above 5%.North Carolina: HHI 3,255; leading share 43%; 3 insurers above 5%.New Mexico: HHI 3,222; leading share 48%; 5 insurers above 5%.Indiana: HHI 2,957; leading share 36%; 3 insurers above 5%.Florida: HHI 2,868; leading share 42%; 3 insurers above 5%.Tennessee: HHI 2,831; leading share 46%; 4 insurers above 5%.Nevada: HHI 2,811; leading share 46%; 6 insurers above 5%.Mississippi: HHI 2,793; leading share 42%; 4 insurers above 5%.Kansas: HHI 2,561; leading share 42%; 5 insurers above 5%.Georgia: HHI 2,464; leading share 40%; 5 insurers above 5%.Missouri: HHI 2,437; leading share 37%; 5 insurers above 5%.Michigan: HHI 2,413; leading share 31%; 5 insurers above 5%.Arizona: HHI 2,410; leading share 30%; 4 insurers above 5%.California: HHI 2,389; leading share 33%; 5 insurers above 5%.Idaho: HHI 2,353; leading share 32%; 4 insurers above 5%.Colorado: HHI 2,334; leading share 32%; 4 insurers above 5%.Texas: HHI 2,311; leading share 40%; 5 insurers above 5%.Pennsylvania: HHI 2,222; leading share 30%; 5 insurers above 5%.Virginia: HHI 2,213; leading share 38%; 6 insurers above 5%.Oregon: HHI 2,071; leading share 26%; 5 insurers above 5%.Washington: HHI 1,772; leading share 29%; 6 insurers above 5%.Ohio: HHI 1,619; leading share 23%; 6 insurers above 5%.OHNew York: HHI 1,582; leading share 30%; 6 insurers above 5%.NYWisconsin: HHI 1,474; leading share 25%; 6 insurers above 5%.WILargest insurer share (%)HHI
NortheastMidwestSouthWestDashed references mark 2,500 HHI and a 50% leading share.

Exact jurisdiction ledger

All 51 rows retain rank, region, HHI, leading share, and rival depth

KFF 2024 ACA individual-insurance concentration by jurisdiction
RankJurisdictionRegionHHILeading shareInsurers above 5%Class
01District of ColumbiaDCSouth6,94581%2Highly concentrated
02AlaskaAKWest6,10274%2Highly concentrated
03IowaIAMidwest5,96575%3Highly concentrated
04DelawareDESouth5,92575%3Highly concentrated
05New HampshireNHNortheast5,80473%3Highly concentrated
06WyomingWYWest5,69569%2Highly concentrated
07VermontVTNortheast5,64868%2Highly concentrated
08Rhode IslandRINortheast5,43365%2Highly concentrated
09HawaiiHIWest5,38564%2Highly concentrated
10UtahUTWest5,30470%3Highly concentrated
11West VirginiaWVSouth5,02557%2Highly concentrated
12ArkansasARSouth4,98353%2Highly concentrated
13ConnecticutCTNortheast4,97554%2Highly concentrated
14North DakotaNDMidwest4,87859%2Highly concentrated
15MarylandMDSouth4,22558%3Highly concentrated
16South CarolinaSCSouth4,16751%3Highly concentrated
17NebraskaNEMidwest4,11656%3Highly concentrated
18AlabamaALSouth3,96347%3Highly concentrated
19MontanaMTWest3,95549%3Highly concentrated
20OklahomaOKSouth3,91657%4Highly concentrated
21MassachusettsMANortheast3,86456%4Highly concentrated
22IllinoisILMidwest3,66657%5Highly concentrated
23KentuckyKYSouth3,64449%3Highly concentrated
24MinnesotaMNMidwest3,54742%3Highly concentrated
25LouisianaLASouth3,45049%4Highly concentrated
26MaineMENortheast3,41443%3Highly concentrated
27South DakotaSDMidwest3,39640%3Highly concentrated
28New JerseyNJNortheast3,38750%3Highly concentrated
29North CarolinaNCSouth3,25543%3Highly concentrated
30New MexicoNMWest3,22248%5Highly concentrated
31IndianaINMidwest2,95736%3Highly concentrated
32FloridaFLSouth2,86842%3Highly concentrated
33TennesseeTNSouth2,83146%4Highly concentrated
34NevadaNVWest2,81146%6Highly concentrated
35MississippiMSSouth2,79342%4Highly concentrated
36KansasKSMidwest2,56142%5Highly concentrated
37GeorgiaGASouth2,46440%5Moderately concentrated
38MissouriMOMidwest2,43737%5Moderately concentrated
39MichiganMIMidwest2,41331%5Moderately concentrated
40ArizonaAZWest2,41030%4Moderately concentrated
41CaliforniaCAWest2,38933%5Moderately concentrated
42IdahoIDWest2,35332%4Moderately concentrated
43ColoradoCOWest2,33432%4Moderately concentrated
44TexasTXSouth2,31140%5Moderately concentrated
45PennsylvaniaPANortheast2,22230%5Moderately concentrated
46VirginiaVASouth2,21338%6Moderately concentrated
47OregonORWest2,07126%5Moderately concentrated
48WashingtonWAWest1,77229%6Moderately concentrated
49OhioOHMidwest1,61923%6Moderately concentrated
50New YorkNYNortheast1,58230%6Moderately concentrated
51WisconsinWIMidwest1,47425%6Below 1,500

Public evidence agenda

Move from a one-year structure screen to mechanisms and outcomes

Open action brief
01Foundation

Firm-level state structure

Publish insurer identities, common-control links, enrollment denominators, and complete state share tables under stable identifiers so HHI and leading-share records can be independently reproduced.

02Immediate

Market event history

Release plan entry, exit, merger, service-area, exchange participation, network, and ownership histories that can explain why jurisdiction structures differ without assigning cause from one cross-section.

03Near-term

Competition outcomes

Connect stable state and insurer identifiers to premiums, actuarial value, claims, denial rates, network breadth, quality, switching, enrollment, and consumer complaints.

04Near-term

Comparable annual panel

Publish consistent annual vintages and revision files so researchers can distinguish structural change from source, reporting, and product-definition changes.

Reproduction packet

Rebuild the distribution and relationships from the public endpoint

The notebook checks exact row count, jurisdiction keys, HHI bounds, source custody, the four headline counts, and the interpretation boundary.
  1. 01

    The public packet returns exactly 51 unique jurisdiction rows for the 2024 individual-insurance system.

  2. 02

    Every HHI stays on the zero-to-10,000 scale and retains the single KFF source ID.

  3. 03

    The median state HHI reproduces 3,414 and 36 jurisdictions meet or exceed 2,500.

  4. 04

    Twenty-one jurisdictions report a leading-insurer share at or above 50 percent.

  5. 05

    Twenty-seven jurisdictions report no more than three insurers above 5 percent.

  6. 06

    The notebook reports the state cross-section and descriptive relationships without extending them to other insurance products, causality, or legal conclusions.

Permanent interpretation boundary

One ACA individual-market cross-section is not a state health-care score.

This cross-section describes the source-defined 2024 ACA-regulated individual health insurance market using KFF state and District of Columbia measures. It does not measure employer-sponsored insurance, Medicare, Medicaid, every insurance product, a state's overall economy, competitive effects, or legal liability. HHI, leading-insurer share, and the count of insurers above 5 percent are structural screens; the public packet does not identify insurers or common control in each jurisdiction.

Executive summary

KFF's 2024 individual-insurance dataset reports a median HHI of 3,414 across the 50 states and District of Columbia. Thirty-six of 51 jurisdictions, or 70.6 percent, report HHI at or above 2,500. Twenty-one jurisdictions report a leading-insurer share at or above 50 percent, and 27 report no more than three insurers with shares above 5 percent. The cross-section ranges from Wisconsin at HHI 1,474 to the District of Columbia at 6,945. Regional medians also differ: 3,864 in the Northeast, 3,644 in the South, 3,177 in the Midwest, and 2,811 in the West. Across the 51 jurisdiction rows, HHI has a descriptive Pearson correlation of 0.959 with leading-insurer share and -0.831 with the count of insurers above 5 percent. Those relationships reconcile internally related structure measures; they are not causal estimates or independent outcome evidence. This packet covers the source-defined 2024 ACA-regulated individual market only. It does not cover employer-sponsored insurance, Medicare, Medicaid, every insurance product, a state's overall economy, competitive effects, or legal liability. The public rows do not identify insurers or common control in each jurisdiction. Stronger research therefore requires firm-level state shares, stable ownership and plan identifiers, annual vintages, entry and exit events, and outcomes including premiums, network breadth, quality, switching, enrollment, claims, and consumer complaints.

36 / 51

jurisdictions at or above 2,500 HHI

70.6% of the complete 2024 KFF jurisdiction field; median HHI is 3,414.

KFF state concentration field

21

jurisdictions with a majority leader

41.2% report a leading-insurer share at or above 50 percent.

KFF leading-share measure

27

jurisdictions with thin rival depth

52.9% report no more than three insurers with shares above 5 percent.

KFF insurer-count measure

5,471

HHI-point cross-section range

Wisconsin reports 1,474; District of Columbia reports 6,945.

Exact jurisdiction ledger

Research map

What this briefing connects

  • National distribution
  • State concentration map
  • Regional comparison
  • Structure relationships
  • Exact jurisdiction ledger
  • Public evidence agenda
  • Reproduction packet
  • Methodology and limits

Source basis

KFF 2024 Individual Insurance Market Competition data for the 50 states and District of Columbia, including source-reported HHI, leading-insurer share, and the count of insurers with more than 5 percent of each jurisdiction's ACA-regulated individual market.

Bounded insurance evidence

Jurisdiction screens reveal structure; they do not score health systems or establish effects.

State concentration atlas

Inspect all 51 rows and three measures

Open route

Reproduction notebook

Validate the distribution and relationships

Open route

KFF source dossier

Audit custody, method, and release

Open route

Methodology and limits matter

This cross-section describes the source-defined 2024 ACA-regulated individual health insurance market using KFF state and District of Columbia measures. It does not measure employer-sponsored insurance, Medicare, Medicaid, every insurance product, a state's overall economy, competitive effects, or legal liability. HHI, leading-insurer share, and the count of insurers above 5 percent are structural screens; the public packet does not identify insurers or common control in each jurisdiction.

Source basis

KFF 2024 Individual Insurance Market Competition data for the 50 states and District of Columbia, including source-reported HHI, leading-insurer share, and the count of insurers with more than 5 percent of each jurisdiction's ACA-regulated individual market.

Source register

1 cited public record

01 / 1
public dataset2024

Source 01

Individual Insurance Market Competition (HHI by state)

KFF

KFF, Individual Insurance Market Competition (HHI by state), 2024 ACA individual market.

State-level HHI leading-insurer share and meaningful-rival measures for the 2024 ACA-regulated individual health insurance market.

Accessed
Jun 23, 2026
Custody
Public research dataset

Research actions

Audit KFF sourceView methodologyBrowse state screens
Public action memoNear-term

What public institutions should do next

Individual-insurance oversight should use the 2024 state concentration cross-section to prioritize disclosure and research, then connect structure to insurer identity, ownership, entry, plan design, networks, prices, quality, switching, and consumer outcomes before assigning cause or legal liability.

Audience

HHS, CMS, FTC, DOJ, Congress, state insurance regulators, state attorneys general, and competition researchers

1Publish complete state insurer-share tablesRelease insurer identities, enrollment shares, common-control links, denominator rules, suppression flags, and reproducible HHI calculations for every jurisdiction under stable identifiers.
2Build a comparable annual market panelPublish annual state vintages with plan entry, exit, mergers, service areas, exchange participation, ownership changes, revisions, and product-definition changes kept explicit.
3Connect structure to public outcomesLink stable state, insurer, and plan identifiers to premiums, actuarial value, claims, denials, network breadth, quality, enrollment, switching, complaints, and geographic access.
4Separate ACA evidence from other insurance systemsKeep employer-sponsored insurance, Medicare, Medicaid, and other product systems in separately documented analytical universes rather than treating one individual-market screen as a state health-care score.
Evidence needed
State insurer identities, enrollment shares, and common controlStable plan, issuer, service-area, and jurisdiction identifiersAnnual entry, exit, merger, exchange, ownership, and revision historiesPremium, actuarial value, claims, denial, network, quality, and switching outcomesSeparate product definitions and denominators across insurance systems
Connect to advocacy playbooks

Policy claims are framed as public-interest asks, not legal conclusions. Each ask should be read with the report’s source basis and limitations.