AR-DN-2026-02Source-backed housing profile note
Central finding
Housing competition cannot be reduced to one national HHI.
Descriptive concentration measures do not by themselves establish competitive harm, unlawful conduct, or a causal effect.
Report evidence navigator
Executive findings
An open brief explaining why housing affordability and supply stress require local competition data before HHI can be responsibly reported.
Public action docket
ForHUD, FTC, DOJ, local housing agencies, and state legislators
Create public registries that identify beneficial ownership, property management, investor class, and common control at local-market geographies.
Condition subsidies, tax incentives, public land deals, and major zoning approvals on auditable ownership and control reporting.
Monitor serial acquisitions, property-management consolidation, and institutional holdings at the metro and neighborhood level.
Evidence still needed
Reader packet
ReusableCanonical citation
Antitrust Radar Research Team. (2026, June 21). Housing Competition Needs Local Ownership Data: Source-backed housing profile note. Public Data Notes, AR-DN-2026-02 (Version 1.0). Antitrust Radar. https://antitrustradar.org/reports/housing-competition-data-gap
Source basis
Harvard JCHS renter cost-burden data, Freddie Mac supply-shortage estimate, GAO selected single-family rental investor ownership data, and FTC/DOJ roll-up inquiry materials.
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Source records
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Related market
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academic paper, industry report, agency report
Source types
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Evidence asks
Evidence index
Published Jun 21, 2026 · sources through Jun 21, 2026 · version 1.0 · Current edition
Read / Briefing claim
Start with the harm theory, market frame, and limits.
Housing choice observatory
Preparing the bounded national context and local ownership evidence.
Table of contents
Executive summary
Housing competition cannot be reduced to one national HHI. Harvard JCHS reports 22.7 million cost-burdened renter households in 2024, Freddie Mac estimates a 3.7 million-home supply shortage as of Q3 2024, and GAO reports that institutional investors owned 22 percent of single-family rental homes in Jacksonville but 4 percent in Seattle in 2024. Those facts show why local market power matters, but they do not provide comparable firm-level local rental market shares. Antitrust Radar therefore publishes the public evidence, labels the local data gap, and withholds HHI until citable firm-level local shares are available.
22.7M
cost-burdened renter households
Harvard JCHS reports the 2024 renter burden that makes local competition evidence urgent.
Harvard JCHS3.7M
home supply shortage
Freddie Mac estimates the U.S. shortage as of Q3 2024, before local ownership shares are visible.
Freddie Mac22% / 4%
selected investor ownership range
GAO reports 22% in Jacksonville and 4% in Seattle, showing why national averages miss local power.
GAONo HHI
without local firm shares
The report withholds HHI until public ownership, control, and rental-share data can support it.
Antitrust Radar ruleResearch map
Source basis
Harvard JCHS renter cost-burden data, Freddie Mac supply-shortage estimate, GAO selected single-family rental investor ownership data, and FTC/DOJ roll-up inquiry materials.
Related markets
This report uses public records and descriptive concentration indicators. It does not claim a legal market definition by itself, and readers should evaluate source vintage, geography, missing firms, and whether the public data measures usage, revenue, prescriptions, passengers, or another proxy.
Harvard JCHS renter cost-burden data, Freddie Mac supply-shortage estimate, GAO selected single-family rental investor ownership data, and FTC/DOJ roll-up inquiry materials.
Source register
Source 01
Harvard Joint Center for Housing Studies
Harvard Joint Center for Housing Studies, America's Rental Housing 2026, released March 2026.
Public research report on U.S. rental housing conditions and renter cost burdens.
Source 02
Freddie Mac
Freddie Mac, Housing Supply: Still Undersupplied by Millions of Units, November 2024.
Freddie Mac estimate of the U.S. housing supply shortage relative to long-run housing demand.
Source 03
Government Accountability Office
Government Accountability Office, Rental Housing: Institutional Investor Ownership of Single-Family Rental Homes, GAO-26-108675, March 2026.
GAO report on institutional investor ownership shares in selected single-family rental housing markets.
Source 04
Federal Trade Commission and Department of Justice
Federal Trade Commission and Department of Justice, Request for Information on Corporate Consolidation Through Serial Acquisitions and Roll-Up Strategies, May 2024.
FTC and DOJ request for information on serial acquisitions and roll-up strategies including housing markets.
Housing competition must be measured locally: affordability stress and supply shortages are public harms, but HHI needs local ownership and control data.
HUD, FTC, DOJ, local housing agencies, and state legislators
Policy claims are framed as public-interest asks, not legal conclusions. Each ask should be read with the report’s source basis and limitations.
Housing choice observatory
Move from public harm to local evidence without turning unlike statistics into a national concentration score.
United States · renter households · 2024
Public next stepTreat affordability pressure as the public stake, then test local supply, ownership, management, and conduct before making a market-power claim.