Where is market power concentrated, how is structure changing, and which competitive mechanism still needs to be tested?
AR-T01 / institutional research topic
Market structure
Market Structure
Where is market power concentrated, how is structure changing, and which competitive mechanism still needs to be tested?Connect definition-bound concentration measures, participant shares, historical movement, and public research questions without collapsing unlike markets into one score.
- Publications9editions
- Agenda questions15questions
- Issue programs6programs
- Public datasets7datasets
- Analysis routes5routes
- Publications
- 9
- 4 permanent series
- Agenda questions
- 15
- 6 issue programs
- Public datasets
- 7
- 14,815 declared rows
- Source links
- 39
- reviewed through Jul 21, 2026
Topic boundary. A concentration measure is a screen inside its stated product, geography, denominator, and period. It is not by itself proof of market power, harm, causation, liability, or the correct legal market.
Evidence standardInstitutional research topicMarket Structure9 publications / 5 active releases / 5 evidence lanes
Research contract
Question, mandate, boundary, and evidence need
Connect definition-bound concentration measures, participant shares, historical movement, and public research questions without collapsing unlike markets into one score.
A concentration measure is a screen inside its stated product, geography, denominator, and period. It is not by itself proof of market power, harm, causation, liability, or the correct legal market.
Comparable participant shares, entry and exit, switching, price, quality, capacity, transactions, and stable market-definition records.
Publication chronology
How this subject entered the public record.
Every institutional release date remains on the axis, including dates with no publication assigned to this topic.- Active releases
- 5 / 6
- Topic publications
- 9
- Largest release
- 2
Publication register
9 citable publications
Exact theme memberships across 4 permanent series.State of CompetitionAR-SC1Methods and MeasuresAR-MM1Public Data NotesAR-DN0Research BriefsAR-RB5Competition InsightsAR-CI2International BriefsAR-ICP0
- AR-CI-2026-01Competition Insights
Domain readout / United States
Latest market-structure signals moved in both directions.
Fifteen HHI, CR4, and leading-share comparisons preserve their own product boundary, denominator, source, and observed interval.- Published
- Aug 12, 2026
- Sources reviewed
- Jul 21, 2026
- Evidence
- 15
- Source links
- 7
- AR-CI-2026-02Competition Insights
Focused note / United States
Four digital usage systems traced four different structural paths.
Browser, mobile operating-system, search-engine, and social-referral shares are read side by side without turning them into one platform-power score.- Published
- Aug 12, 2026
- Sources reviewed
- Jul 20, 2026
- Evidence
- 12
- Source links
- 4
- AR-RB-2026-06Competition Research Briefs
Research brief / United States
Fixed Broadband Concentration Across Geographic Scales, 2020-2024
A four-scale FCC concentration history showing why a rising national HHI and falling subnational medians must be read together without converting them into one market.- Published
- Jul 24, 2026
- Sources reviewed
- Jul 21, 2026
- Evidence
- 1
- Source links
- 1
- AR-RB-2026-07Competition Research Briefs
Research brief / United States
State Individual Insurance Concentration, 2024
A 51-jurisdiction KFF concentration cross-section showing where high HHI, leading-insurer share, and thin rival depth coincide, with every result bounded to the 2024 ACA individual market.- Published
- Jul 24, 2026
- Sources reviewed
- Jun 23, 2026
- Evidence
- 1
- Source links
- 1
- AR-RB-2026-02Competition Research Briefs
Research brief / United States
Five Digital Gateways
Five system histories, exact share rows, official product-attribution paths, and a public research agenda with every denominator kept separate.- Published
- Jul 20, 2026
- Sources reviewed
- Jul 20, 2026
- Evidence
- 5
- Source links
- 5
- AR-RB-2026-03Competition Research Briefs
Research brief / United States
State Banking Structure, 2015-2025
Shows how a nearly unchanged national HHI can coexist with large state-level movements, classification turnover, and declining branch and organization counts.- Published
- Jul 20, 2026
- Sources reviewed
- Jul 19, 2026
- Evidence
- 1
- Source links
- 1
- AR-RB-2026-01Competition Research Briefs
Research brief / United States
Beef Meatpacking Buyer Power
Explains what the national beef-packer CR4 reveals, why HHI remains withheld, and how the related Census industry screen should be used without redefining a cattle procurement market.- Published
- Jul 19, 2026
- Sources reviewed
- Jul 19, 2026
- Evidence
- 3
- Source links
- 3
- AR-SC-2026-01State of Competition
State of competition report / United States
The U.S. Competition Landscape
A source-backed state-of-competition briefing across markets, industries, state systems, local banking screens, mergers, and enforcement, with every system kept in its own analytical universe.- Published
- Jul 19, 2026
- Sources reviewed
- Jul 19, 2026
- Evidence
- 14
- Source links
- 14
- AR-MM-2026-01Methods and Measures
Methodology primer / United States
How HHI Helps Explain Market Concentration
A short public-interest guide to reading descriptive concentration metrics.- Published
- May 16, 2026
- Sources reviewed
- Jul 17, 2026
- Evidence
- 3
- Source links
- 3
Evidence systems
Questions, programs, datasets, and analysis routes
Research agenda
15 bounded questions- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Beef meatpacking / Four-participant concentration ratio
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Browsers / Four-participant concentration ratio
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Browsers / Herfindahl-Hirschman Index
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Browsers / Leading-participant share
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Fixed broadband / Herfindahl-Hirschman Index
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Mobile operating systems / Four-participant concentration ratio
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Mobile operating systems / Herfindahl-Hirschman Index
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Mobile operating systems / Leading-participant share
Show 7 more questions
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Search engines / Four-participant concentration ratio
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Search engines / Herfindahl-Hirschman Index
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Search engines / Leading-participant share
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Social referrals / Four-participant concentration ratio
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Social referrals / Herfindahl-Hirschman Index
- SharesWhich participant-share changes account for the structural movement, and are the denominator and coverage stable across both anchors?Social referrals / Leading-participant share
- MechanismWhich entry, exit, share, switching, price, quality, or capacity evidence can explain the movement inside this exact market boundary?Wireless service / Herfindahl-Hirschman Index
Issue programs
6 editorial programs- 105 evidence linksDigital platform gatewaysHow do defaults, distribution agreements, data access, and adjacent-platform positions shape entry across separately measured digital systems?
- 19 evidence linksCommunications infrastructureWhere do local communications concentration, network access, switching, and investment constrain rivalry across separately measured wireless and fixed systems?
- 26 evidence linksHealth care intermediariesHow do insurer structure, PBM contracting, rebate, formulary, network, and organizational relationships affect competition and patient access across separately measured health-care systems?
- 16 evidence linksHousing access and local powerWhich local ownership, pricing, supply, and platform records can identify where renters face weakened competitive choice?
- 23 evidence linksTransportation networksHow do route-level entry, capacity, airport constraints, and consolidation shape passenger choice beyond national shares?
- 10 evidence linksFood systems and buyer powerHow does buyer concentration in regional cattle procurement affect producer options, contract terms, and supply-chain resilience?
Public datasets
7 reusable contracts- 12 rows / 38 fieldsMarket profilesProfile-level market definitions, exact concentration measures, source custody, and deterministic public-interest briefs that keep structure, change, evidence gaps, and action questions separate.
- 12 rows / 9 fieldsMarket definitionsStructured product boundaries, geographies, denominators, inclusions, exclusions, metric families, and permitted comparison uses.
- 32 rows / 4 fieldsMarket observationsYearly concentration observations with HHI, calculation method, confidence labels, and methodology notes.
- 162 rows / 8 fieldsParticipant sharesFirm, product, service, or aggregate share observations used for top-participant, CR4, and source-coverage calculations.
- 65 rows / 16 fieldsMarket trend seriesDefinition-aware HHI, CR4, and leading-participant anchors with normalization baselines, source custody, and comparison guardrails.
- 105 rows / 29 fieldsHHI change decompositionParticipant-level share-squared contributions for adjacent, definition-stable market releases, with residual-firm assumptions, possible HHI-change bounds, endpoint classifications, source custody, and non-causal guardrails.
- 14,427 rows / 25 fieldsAntitrust indicatorsNormalized, source-custodied observations for bounded national-context, market, industry, state, and federal merger-activity indicators, plus 15 exact entity-period relationship contracts and a guarded multidimensional cube mode that retain each series' unit and boundary.
Analysis routes
5 declared handoffs- 01 / profileMarket profilesDefinition-bound concentration dossiers
- 02 / dataIndicator observatoryNormalized measures and evidence coverage
- 03 / researchTrend explorerHistorical HHI, CR4, and leader-share paths
- 04 / compareCompare marketsSame-measure histories and evidence gaps
- 05 / researchPublished rankingsOrdered screens with visible universes
Topic collection citation
Open publication citations Antitrust Radar. (2026). Market Structure [Research topic]. Antitrust Radar.