Stablecoin Market Concentration Index (HHI)
· Updated daily at 15:20 UTC
As of Jul 2026, the stablecoin market Herfindahl-Hirschman Index (HHI) stands at 4322, well above the 1,800 threshold the Department of Justice and FTC use under the 2023 Merger Guidelines[1] to classify a market as highly concentrated. An HHI of 4322 means stablecoin market share is held by a small number of large issuers, so a disruption at one of the largest issuers could affect a large fraction of the market. For policymakers, this concentration warrants monitoring; the HHI scale was designed for product-market competition rather than for stablecoin systemic risk, but it remains a useful concentration benchmark. For enterprise treasury teams, it raises counterparty diversification considerations. The index has remained persistently above 3,500 since mid-2025. We publish HHI as a live daily time series, covering 449 daily snapshots from Apr 2025 to present.
Stablecoin Market Concentration Index (HHI)
Daily HHI calculated across all tracked stablecoins. The red dashed line marks the DOJ/FTC highly concentrated threshold (1,800 under the 2023 Merger Guidelines). The green dashed line marks the moderately concentrated threshold (1,000). Updated daily from CoinGecko snapshots.
Multiple issuers hold comparable market shares. Most diversified industries fall in this range. The US commercial banking sector by branch count, for example, is in the unconcentrated band.
For policymakers: Low antitrust concern under the current 2023 Merger Guidelines[1]. For enterprise: A diversified counterparty landscape, with limited single-issuer exposure.
A small number of issuers hold dominant positions but the market is not monopolized. Regulators monitor but do not typically intervene. Common in concentrated but functional industries.
For policymakers: Warrants monitoring under the 2023 Merger Guidelines[1]. For enterprise: Some concentration risk; consider exposure across at least two major stablecoins.
Under the 2023 DOJ/FTC Merger Guidelines[1], mergers that push the HHI above 1,800 (with a change of more than 100) are presumed to harm competition. A disruption at one of the largest issuers could affect a large fraction of stablecoin supply.
For policymakers: The antitrust scale was designed for product markets, not systemic risk, but high HHI is a concentration signal worth monitoring. For enterprise: Single-issuer risk is significant; a contingency stablecoin strategy is worth considering.
End-of-quarter HHI readings. A declining HHI signals growing market diversity; a rising HHI signals increasing concentration.
| Quarter | HHI | Change | Level |
|---|---|---|---|
| Q2 2025 | 4688 | — | Highly Concentrated |
| Q3 2025 | 4224 | -464 | Highly Concentrated |
| Q4 2025 | 4448 | +224 | Highly Concentrated |
| Q1 2026 | 4284 | -163 | Highly Concentrated |
| Q2 2026 | 4323 | +39 | Highly Concentrated |
Data coverage: Apr 2025 – Jul 2026. Source: CoinGecko daily snapshots processed by Stablecoin Beat.
Coin HHI measures concentration across individual stablecoins. Issuer HHI groups those coins by the company or protocol behind them, revealing true economic concentration. Sky/MakerDAO issues both DAI and USDS; Ethena issues both USDE and sUSDe. Issuer-level HHI is the more relevant metric for systemic risk and regulatory analysis: a single issuer disruption affects all their coins simultaneously.
Issuer HHI, Market Concentration by Company
Daily HHI computed on issuer-aggregated market caps. Sky/MakerDAO (DAI + USDS + sUSDS), Ethena (USDE + sUSDe + USDtb), Circle (USDC + EURC), and Tether (USDT + EURT) are each counted as single issuers. The result is a truer picture of systemic concentration than coin-level HHI.
Current Issuer Market Share, Top 12
Market cap share by issuer from the latest snapshot. Each bar represents one issuing entity's combined stablecoin footprint. The two-issuer oligopoly (Tether + Circle) is immediately visible.
Theil T Index, Inequality Decomposition
The Theil T index measures inequality in market share distribution across issuers. Unlike HHI, Theil is additively decomposable: it can be split into within-group and between-group inequality. Formula: T = Σ si × ln(si × N). Range: 0 (perfect equality) to ln(N) (monopoly). Current value of 3.825 represents 74% of the theoretical maximum for the tracked issuer set.
Formula: HHI = Σ (si)² × 10,000, where si = market cap of coin i ÷ total stablecoin market cap, computed across all stablecoins in each daily snapshot.
Data source: CoinGecko API (daily snapshots). Update frequency: Daily at ~15:30 UTC. Coverage: Apr 2025 – present (449 snapshots).
Thresholds: Based on DOJ/FTC Horizontal Merger Guidelines, below 1,500: competitive; 1,500–2,500: moderately concentrated; above 2,500: highly concentrated.
Limitation: HHI is computed on market cap, not transaction volume or economic influence. A stablecoin with high market cap but low velocity may overstate its systemic importance relative to actual usage. Future versions will incorporate volume-weighted variants.
- U.S. Department of Justice and Federal Trade Commission. 2023. Merger Guidelines. December 18, 2023. The 2023 Guidelines lower the highly-concentrated HHI threshold from 2,500 (2010 Guidelines) to 1,800. ftc.gov/system/files/ftc_gov/pdf/2023_merger_guidelines_final_12.18.2023.pdf
- Financial Action Task Force. 2026. "Targeted Report on Stablecoins and Unhosted Wallets: Peer-to-Peer Transactions." March 2026. fatf-gafi.org/en/publications/Virtualassets/targeted-report-stablecoins-unhosted-wallets.html