Market concentration rankings

Compare published concentration measures, changes, and data gaps within their stated market definitions. Rankings help identify research questions; they do not rank legal violations.

Open workbench View table

Ranked rows

Top firm

Tracked markets

all sectors

Source-backed

public rows

Disclosure gaps

active lens

Active lens route

Leading signal: Search engines. 6 source-backed rows route to public action: investigate.

Top firm

LensTop firm6 ranked rows Top signalSearch engines85.2%Evidence6 backedestimated public ActionInvestigateSearch engines

PlotTop 5 Table6 rows ScatterCompare Network6 backed TreemapFirms APIJSON

Leading signals

Exact values under the active ranking lens.

Top firm

Evidence · 6 rows Investigate

Rank by

Highest HHI8 Top-firm share6 CR46 Increasing concentration4 Data gaps4

Public-interest screen

Top firm

The active ranking connects concentration metrics to source status, market definition, and government action questions.

PlotTop 5exact ranking Table6 rowsranked leaders ScatterComparemarket lens Network6 backedsource route TreemapFirmsshare structure APIJSONpublic rows

Ranked distribution

Leading markets under top-firm share

6 rows · exact values

Lens distribution

6 rows

Source-backed6rows with public evidence High concern6HHI, CR4, or top-firm flags Disclosure gaps1missing or low-confidence facts Public queue6Investigate

Top-firm share

Markets ranked by the largest firm’s share in the latest participant data.

6 markets match this lens; leading signal: Search engines with 85.2%.

Evidence packet

U.S. search engine usage

Digital platforms · United States

HHI

7,359

CR4

99.4%

Top firm

85.2%

Source basis: StatCounter Global Stats.

Public-use route

Copy the citation line or filtered market API endpoint for notes, notebooks, and reproducible research.

JSON CSV

Open market profile

Government action path

1Publish market-share tables

2Explain entry and switching barriers

3Tie remedies to prices, choice, quality, and access

Research desk

Move from screen to evidence.

Ranking6 ranked rows

HHI8 marketsOpen Top firm6 marketsActive CR46 marketsOpen Rising4 marketsOpen Data gaps4 marketsOpen

Source-backed onlyAbout rankings

Ranking workbench

Find the market behind the signal.

6 of 6 markets match this lens after search and evidence filters.

Top-firm share ranking

Markets ranked by the largest firm’s share in the latest participant data.

Each row is a public evidence packet: exact metrics, source status, data freshness, action cue, and a machine-readable route. No composite score is used; signal basis lists the published metric flags behind each cue.

ranked rows

high concern

data gaps

source-backed

Rank #1

Search engines

Digital platforms

Investigate

HHI

7,359

CR4

99.4%

Top firm

85.2%

StatCounter Global Stats

1 source · reviewed Jul 17, 2026

Profile Open data

Rank #2

Social referrals

Digital platforms

Investigate

HHI

4,995

CR4

94.4%

Top firm

68.9%

StatCounter Global Stats

1 source · reviewed Jul 20, 2026

Profile Open data

Rank #3

AI assistants

Digital platforms

Investigate

HHI

4,804

CR4

94.8%

Top firm

67.1%

StatCounter Global Stats

1 source · reviewed Jun 23, 2026

Profile Open data

Rank	Market	HHI	CR4	Top firm	Class	Signal basis	Evidence	Action
1	U.S. search engine usage Digital platforms · United States 1 source	7,359	99.4%	85.2%	Highly concentrated	HHI >= 2,500 CR4 >= 60% Top firm >= 35%	Public estimate StatCounter Global Stats Reviewed Jul 17, 2026 Reuse evidence JSON CSV	Investigate Probe entry barriers, switching costs, pricing, and remedies.
2	U.S. social-media referral traffic Digital platforms · United States 1 source	4,995	94.4%	68.9%	Highly concentrated	HHI >= 2,500 CR4 >= 60% Top firm >= 35% HHI +1,602 since 2023	Public estimate StatCounter Global Stats Reviewed Jul 20, 2026 Reuse evidence JSON CSV	Investigate Probe entry barriers, switching costs, pricing, and remedies.
3	U.S. generative AI assistant usage Digital platforms · United States 1 source	4,804	94.8%	67.1%	Highly concentrated	HHI >= 2,500 CR4 >= 60% Top firm >= 35%	Public estimate StatCounter Global Stats Reviewed Jun 23, 2026 Reuse evidence JSON CSV	Investigate Probe entry barriers, switching costs, pricing, and remedies.
4	U.S. mobile operating-system web usage Digital platforms · United States 1 source	5,337	100.0%	63.1%	Highly concentrated	HHI >= 2,500 CR4 >= 60% Top firm >= 35% HHI +180 since 2023	Public estimate StatCounter Global Stats Reviewed Jul 20, 2026 Reuse evidence JSON CSV	Investigate Probe entry barriers, switching costs, pricing, and remedies.
5	U.S. browser usage Software · United States 1 source	3,612	93.8%	50.0%	Highly concentrated	HHI >= 2,500 CR4 >= 60% Top firm >= 35%	Public estimate StatCounter Global Stats Reviewed Jul 17, 2026 Reuse evidence JSON CSV	Investigate Probe entry barriers, switching costs, pricing, and remedies.
6	U.S. domestic airline passengers Transportation · United States 1 source	Withheld	69.0%	17.8%	Not calculated	HHI withheld CR4 >= 60% Data incomplete	Incomplete Bureau of Transportation Statistics Reviewed May 16, 2026 Reuse evidence JSON CSV	Disclose data Request firm-level shares and reusable public tables.

#1 · Digital platforms

U.S. search engine usage

United States

HHI

7,359

CR4

99.4%

Top firm

85.2%

Signal basis

HHI >= 2,500
CR4 >= 60%
Top firm >= 35%

Highly concentratedEstimated from public dataInvestigate

StatCounter Global Stats

1 source · reviewed Jul 17, 2026

Probe entry barriers, switching costs, pricing, and remedies.

Profile

Reuse evidenceCite · API · files

JSON CSV

#2 · Digital platforms

U.S. social-media referral traffic

United States

HHI

4,995

CR4

94.4%

Top firm

68.9%

Signal basis

HHI >= 2,500
CR4 >= 60%
Top firm >= 35%
HHI +1,602 since 2023

Highly concentratedEstimated from public dataInvestigate

StatCounter Global Stats

1 source · reviewed Jul 20, 2026

Probe entry barriers, switching costs, pricing, and remedies.

Profile

Reuse evidenceCite · API · files

JSON CSV

#3 · Digital platforms

U.S. generative AI assistant usage

United States

HHI

4,804

CR4

94.8%

Top firm

67.1%

Signal basis

HHI >= 2,500
CR4 >= 60%
Top firm >= 35%

Highly concentratedEstimated from public dataInvestigate

StatCounter Global Stats

1 source · reviewed Jun 23, 2026

Probe entry barriers, switching costs, pricing, and remedies.

Profile

Reuse evidenceCite · API · files

JSON CSV

Show 3 more ranked markets

#4 · Digital platforms

U.S. mobile operating-system web usage

United States

HHI

5,337

CR4

100.0%

Top firm

63.1%

Signal basis

HHI >= 2,500
CR4 >= 60%
Top firm >= 35%
HHI +180 since 2023

Highly concentratedEstimated from public dataInvestigate

StatCounter Global Stats

1 source · reviewed Jul 20, 2026

Probe entry barriers, switching costs, pricing, and remedies.

Profile

Reuse evidenceCite · API · files

JSON CSV

#5 · Software

U.S. browser usage

United States

HHI

3,612

CR4

93.8%

Top firm

50.0%

Signal basis

HHI >= 2,500
CR4 >= 60%
Top firm >= 35%

Highly concentratedEstimated from public dataInvestigate

StatCounter Global Stats

1 source · reviewed Jul 17, 2026

Probe entry barriers, switching costs, pricing, and remedies.

Profile

Reuse evidenceCite · API · files

JSON CSV

#6 · Transportation

U.S. domestic airline passengers

United States

HHI

Withheld

CR4

69.0%

Top firm

17.8%

Signal basis

HHI withheld
CR4 >= 60%
Data incomplete

Not calculatedIncomplete dataDisclose data

Bureau of Transportation Statistics

1 source · reviewed May 16, 2026

Request firm-level shares and reusable public tables.

Profile

Reuse evidenceCite · API · files

JSON CSV

Reusable ranking packet

Top-firm share

Export the current public filters as JSON, CSV, or a data-console route so ranking claims can move into notes, notebooks, and public action.

Top firm

lens rows

source backed

api filters

The packet uses the same structured filters available in the public API grammar.

View lensranking page Markets JSONfiltered rows CSV exportspreadsheet-ready Data consolesame filters Action queueSearch engines

Compare markets

Outlier lens: Top-firm share

Markets ranked by the largest firm’s share in the latest participant data.

Selected

Highest HHI

7,359

Data gaps

Cross-market definition guardrail

The same 0-10,000 HHI scale does not make different product, geographic, or denominator definitions economically interchangeable. Cross-market HHI is a descriptive screen only.

Inspect definitions

Selected markets

Search engines + Social referrals + AI assistants

Evidence packets

3 public sources

Disclosure pressure

No gaps selected

Action queue

Investigate

Research handoff

Comparison packet ready.

Selected evidence packets

Search engines
Digital platforms
Investigate
HHI
7,359
CR4
99.4%
Top
85.16%
Profile Data
Reusable route
7,359 HHI with medium confidence. Measurement basis: StatCounter search engine referral usage share.
Public proxy · Screen only · Comparable anchors
JSON Definition
Action route
Social referrals
Digital platforms
Investigate
HHI
4,995
CR4
94.4%
Top
68.94%
Profile Data
Reusable route
4,995 HHI with medium confidence. Measurement basis: StatCounter all-platform social-media referral share.
Public proxy · Screen only · Comparable anchors
JSON Definition
Action route
AI assistants
Digital platforms
Investigate
HHI
4,804
CR4
94.8%
Top
67.13%
Profile Data
Reusable route
4,804 HHI with medium confidence. Measurement basis: StatCounter all-platform AI chatbot usage share.
Public proxy · Screen only · Snapshot only
JSON Definition
Action route

The plot uses sourced HHI when available and keeps withheld-HHI markets on a visible data-gap rail instead of inventing shares.

Historical release lab

Market ranking time machine

Compare exact sourced release frames. Missing markets stay absent, and rank movement is measured against the prior published frame without interpolation or carry-forward.

Open figure

Release frame

2026

HHI

Observed markets

5/12

tracked universe

Prior release

2025

4 shared markets

Universe change

+1 / -0

5 sources

Exact 2026 frame

Herfindahl-Hirschman Index

Source-reported or reproducibly calculated HHI anchors.

5 released

Rank roseRank fellEntered frameRanks use only observed rows in each release.

Selected release row

Search engines

Digital platforms / 2026

Estimated Public

Rank: #1
HHI: 7,359
Movement: Held
Confidence: Medium

Source custody

StatCounter Global Stats

Search engine market share in United States of America April 2026

-230 HHI since prior release

HHI is computed from listed StatCounter percentages and a small residual Other category equal to 100 minus listed shares.

Market profile Exact figure Source profile Source release

Cross-release cohort

Market rank trajectories

Follow a chosen cohort through the full observed ranking universe in each exact release. Rank denominators can change as markets enter or leave a published frame.

Cohort markets

4 selected / 5 maximum

Minimum 2; ranks retain every observed market in the release.

AI assistants1 release / through 2026Browsers4 releases / through 2026Fixed broadband5 releases / through 2024Individual insurance1 release / through 2024Mobile operating systems4 releases / through 2026Search engines4 releases / through 2026Social referrals4 releases / through 2026Wireless service3 releases / through 2023

Release frames

42023-2026

Cohort anchors

164 selected markets

Explicit gaps

0no fill or carry-forward

Source releases

44 complete series

Global rank / exact releases

Herfindahl-Hirschman Index

Cursor 2026

2026 release row

Search engines

Digital platforms

Global rank: #1 / 5
HHI: 7,359
Movement: Held
Evidence: Medium

Source custody

StatCounter Global StatsSearch engine market share in United States of America April 2026

HHI is computed from listed StatCounter percentages and a small residual Other category equal to 100 minus listed shares.

Market profile Source release

Release rule

Each rank is recalculated from every observed market in that exact metric release. Missing observations remain absent.

Definition rule

Product boundaries, geographies, and source scopes remain distinct. Rank movement is a research screen, not a legal market conclusion.

Public interest triage

Public action queue: Top-firm share

Rankings shouldn’t stop at naming concentrated markets. This queue turns the active lens into a public-interest docket for data disclosure, investigation, and remedy design.

Queue order uses the review category, latest sourced HHI, and visible trigger count. It does not estimate consumer harm or establish legal liability.

Immediate

Near-term

Data gaps

Agency-ready

Open advocacy agenda Audit sources

#1Immediate reviewHHI 7,359
Search engines
Digital platforms · United States · medium confidence · estimated public
3
exact flags
Review basis
HHI 7,359 (>= 2,500)85.2% top firm (>= 35%)99.4% CR4 (>= 60%)
Public action
Test whether the dominant firm controls access, switching, pricing, defaults, distribution, or other chokepoints that weaken consumer choice.
Evidence needed
Agency-ready source trail and market-definition caveats
#2Immediate reviewHHI 5,337
Mobile operating systems
Digital platforms · United States · medium confidence · estimated public
4
exact flags
Review basis
HHI 5,337 (>= 2,500)63.1% top firm (>= 35%)100.0% CR4 (>= 60%)HHI trend increasing
Public action
Test whether the dominant firm controls access, switching, pricing, defaults, distribution, or other chokepoints that weaken consumer choice.
Evidence needed
Agency-ready source trail and market-definition caveats
#3Immediate reviewHHI 4,995
Social referrals
Digital platforms · United States · medium confidence · estimated public
4
exact flags
Review basis
HHI 4,995 (>= 2,500)68.9% top firm (>= 35%)94.4% CR4 (>= 60%)HHI trend increasing
Public action
Test whether the dominant firm controls access, switching, pricing, defaults, distribution, or other chokepoints that weaken consumer choice.
Evidence needed
Agency-ready source trail and market-definition caveats
#4Immediate reviewHHI 4,804
AI assistants
Digital platforms · United States · medium confidence · estimated public
3
exact flags
Review basis
HHI 4,804 (>= 2,500)67.1% top firm (>= 35%)94.8% CR4 (>= 60%)
Public action
Test whether the dominant firm controls access, switching, pricing, defaults, distribution, or other chokepoints that weaken consumer choice.
Evidence needed
Comparable multi-year observations