Stablecoin Market Concentration Index (HHI)
· Updated daily at 15:20 UTC
As of May 2026, the stablecoin market Herfindahl-Hirschman Index (HHI) stands at 3907 — well above the 2,500 threshold the Department of Justice uses to classify a market as highly concentrated. An HHI of 3907 means the stablecoin market is dominated by a small number of large issuers, with a single operator disruption capable of cascading across the entire ecosystem. For policymakers, this concentration level warrants close monitoring: the stablecoin market is significantly more concentrated than most traditional financial sectors including US bank deposits. For enterprise treasury teams evaluating stablecoin adoption, it raises counterparty diversification risk. The index has remained persistently above 3,500 since mid-2025, suggesting structural rather than cyclical concentration. Stablecoin Beat is the first platform to publish HHI as a live daily time series, covering 415 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 (2,500). The green dashed line marks the competitive threshold (1,500). Updated daily from CoinGecko snapshots.
Multiple issuers hold comparable market shares with no single point of systemic failure. The US commercial banking sector typically falls in this range (~800–1,200).
For policymakers: Low systemic concentration risk. For enterprise: Diversified counterparty landscape — safe to hold multiple stablecoins without 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 and disclosure requirements. For enterprise: Some concentration risk — consider maintaining exposure to at least two major stablecoins.
In traditional markets, the DOJ/FTC consider mergers in this range presumptively harmful to competition. One or two issuers control systemic risk. A disruption at the largest issuer could destabilize the entire market.
For policymakers: Systemic risk concentration. Requires resilience and contingency planning. For enterprise: Single-issuer risk is significant — a contingency stablecoin strategy is essential.
End-of-quarter HHI readings. A declining HHI signals growing market diversity; a rising HHI signals increasing concentration.
| Quarter | HHI | Change | Level |
|---|---|---|---|
| Q2 2025 | 4377 | — | Highly Concentrated |
| Q3 2025 | 3823 | -554 | Highly Concentrated |
| Q4 2025 | 4066 | +243 | Highly Concentrated |
| Q1 2026 | 3814 | -252 | Highly Concentrated |
| Q2 2026 | 3907 | +93 | Highly Concentrated |
Data coverage: Apr 2025 – May 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 4.096 represents 73% 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 (415 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.