Daily Herfindahl-Hirschman Index tracking stablecoin market concentration, at coin and issuer level.
As of October 11, 2026, the stablecoin market had a Herfindahl-Hirschman Index of 4,436 at coin level and 4,452 at issuer level. The two largest issuers together accounted for 85.4% of supply.
As of Oct 2026, the stablecoin market Herfindahl-Hirschman Index (HHI) stands at 4,436, 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 4,436 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 within the same broad range over the past year, indicating that the market's high degree of concentration has changed relatively little despite shifts in supply between individual stablecoins and issuers.
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: Falls within the moderately concentrated range 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 vs prior | Level |
|---|---|---|---|
| Q4 2026 | 4436 | +22 | Highly Concentrated |
| Q3 2026 | 4413 | -77 | Highly Concentrated |
| Q2 2026 | 4490 | +69 | Highly Concentrated |
| Q1 2026 | 4422 | -218 | Highly Concentrated |
| Q4 2025 | 4640 | +179 | Highly Concentrated |
| Q3 2025 | 4461 | -443 | Highly Concentrated |
| Q2 2025 | 4904 | — | Highly Concentrated |
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.
Compliance & Settlement Risk: USDT's issuer concentration creates counterparty risk for institutions with settlement exposure. The Issuer HHI measures how much of the market a single company controls, at 4,452, a single-issuer event (regulatory action, reserve crisis, or technical failure at Tether) would affect the majority of global stablecoin settlement volume. FATF has also highlighted stablecoin misuse risks, including cases involving USDT on Tron in laundering and unhosted-wallet contexts[2].
The Theil T index ranges from zero, when every issuer has an equal share of the market, to ln(N), when a single issuer accounts for the entire market and N is the number of issuers observed.
Because that theoretical maximum rises with the number of issuers, the raw index is best read alongside its share of the maximum. That percentage provides the more useful comparison over time. A low reading indicates a market in which supply is spread across a broad set of meaningful participants; a reading close to the maximum points to a market dominated by a single issuer.
Theil rises when market share shifts from smaller issuers towards larger ones, and falls when supply becomes more evenly distributed.
Unlike measures that are driven primarily by the largest participants, Theil is sensitive to changes across the full distribution. It compares each issuer's share with the market's average share, allowing movements among smaller issuers to register even when they have little effect on the Herfindahl-Hirschman Index.
That distinction can be informative. If the HHI rises while Theil remains broadly unchanged, for example, it suggests that concentration is increasing mainly through shifts in market share among the largest issuers, rather than through a broader transfer of supply away from the market's smaller participants.
The two measures capture different aspects of market structure.
The HHI squares each issuer's market share, giving disproportionate weight to the largest participants and making it relatively insensitive to changes in the tail of the distribution. Theil, by contrast, reflects inequality across the market as a whole.
It also has the advantage of being additively decomposable: overall inequality can be separated into differences within groups and differences between them.
In practical terms, the HHI asks how concentrated the market is among its largest issuers. Theil asks how unevenly supply is distributed across the entire issuer base. Read together, they provide a fuller picture of concentration than either measure can offer on its own.
Formula: HHI = Σ (si)² × 10,000, where si = market cap of coin i ÷ total stablecoin market cap, computed across all stablecoins each day.
Theil T formula: T = Σ si × ln(si × N), computed on issuer-aggregated market shares. Range: 0 (perfect equality) to ln(N) (monopoly), where N is the number of tracked issuers. Reported both as a level and as a percentage of that theoretical maximum.
Updated daily. See the methodology for data sources and coverage.
Thresholds: Based on the 2023 DOJ/FTC Merger Guidelines: below 1,000: unconcentrated; 1,000–1,800: moderately concentrated; above 1,800: highly concentrated.[1]
Lens: Concentration is measured by issuer of record, meaning the regulated or operating entity responsible for issuing the coin, rather than the brand attached to the token. PYUSD is therefore attributed to Paxos Trust Company, despite carrying the PayPal brand. USDtb, USDGO and USA₮ are attributed to Anchorage Digital Bank, although they are branded by Ethena, OSL and Tether respectively. A brand-based view is available as an alternative cut of the market, but it is not the basis of the published concentration measure.
Coverage: Issuers are named for about 100.0% of tracked supply, while the issuer of record has been verified for 99.9%. The 0.05 percentage-point gap comprises two coins that remain grouped under their brands while verification of the issuing entity is outstanding. Where the issuer of record cannot be verified, the coin is treated as a standalone unit. No affiliation is inferred without supporting evidence.
Direction of bias: This treatment gives the measure a clear direction of bias. Unattributed coins are split into standalone units rather than combined with a possible parent issuer, so gaps in attribution can only reduce measured issuer concentration. The published figure is therefore a lower bound with respect to attribution gaps, which currently account for 0.02% of tracked supply.
Worked example: The distinction is clearest in the treatment of Ethena. USDE and sUSDe remain grouped under Ethena, while USDtb is attributed to Anchorage Digital Bank as its issuer of record. The same principle is applied throughout the measure: economic or consumer branding does not override the legal issuing entity.
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.
The Herfindahl-Hirschman Index, or HHI, measures how concentrated the stablecoin market is across issuers.
It is calculated by squaring the percentage market share of every participant and adding those figures together. The index runs as high as 10,000. A single issuer controlling 100% of the market would produce an HHI of 10,000, while a market divided evenly among 100 issuers would produce an HHI of 100.
The current stablecoin HHI is 4,436, which is classified here as Highly Concentrated. Over the past 90 days, the index changed by -104.
US merger guidelines provide useful reference points for interpreting market concentration, although those thresholds were designed for antitrust analysis rather than stablecoins or payment infrastructure. They should therefore be treated as context, not as a judgment about whether the stablecoin market is healthy or unsafe.
HHI can reveal concentration changes that a single dominance figure misses because larger market shares receive much more weight. A few percentage points moving between the two largest stablecoin issuers can move the index substantially more than the same shift among smaller issuers.
Coin-level HHI treats each stablecoin as a separate market participant. Issuer-level HHI instead groups stablecoins according to the company, institution or protocol responsible for issuing them. An issuer operating several coins is therefore counted once, using its combined share of supply.
For assessing systemic risk, the issuer-level measure is generally the more informative of the two. Many of the shocks that matter to stablecoin holders occur at issuer level: regulatory action, problems with reserves, banking disruption or a technical failure can affect several coins issued by the same entity simultaneously.
The distinction can therefore reveal concentration that is obscured when individual coins are considered separately. Coin-level HHI currently stands at 4,436, compared with an issuer-level reading of 4,452.
Issuer attribution follows the issuer of record, the entity legally or operationally responsible for issuing the instrument. That may differ from the brand under which a stablecoin is marketed.
The Theil T index measures how unevenly stablecoin supply is distributed across issuers. It is calculated as T = Σ sᵢ × ln(sᵢ × N), where sᵢ is an issuer's share of total supply and N is the number of issuers tracked.
The index ranges from zero, when every issuer has an equal share, to ln(N), when a single issuer accounts for the entire market. The current reading is 3.602, equivalent to 94% of its theoretical maximum. Expressing the index as a proportion of that maximum makes comparisons over time more meaningful when the number of issuers changes.
The Theil index and the Herfindahl-Hirschman Index, or HHI, capture different dimensions of market structure. Because the HHI squares each participant's market share, it is driven disproportionately by the largest issuers. Changes among smaller participants therefore have relatively little effect on the headline figure.
Theil, by contrast, takes account of the full distribution of supply. It can therefore register changes among smaller issuers that might leave the HHI almost unchanged. In broad terms, the HHI is a measure of concentration, particularly at the top of the market, while Theil measures how unevenly supply is distributed across the issuer base as a whole.
Theil also has an important analytical advantage: it is additively decomposable. Overall inequality can be separated into inequality within groups and inequality between them, for example, between regulated and unregulated issuers or across different peg currencies. That makes it especially useful when the question is not simply how unequal the market is, but where that inequality originates.
Unlike the HHI, however, Theil has no official interpretation bands. Competition authorities publish commonly used HHI thresholds for assessing market concentration; there is no equivalent standard for Theil. It is therefore best read relative to its theoretical maximum and, importantly, by the direction and scale of its movement over time.
Yes. The US commercial banking sector typically has an HHI between 800 and 1,200, well within the competitive range. The stablecoin market at 4,436 is approximately three to four times more concentrated than most regulated financial markets, driven primarily by Tether's dominant market position.
A concentrated stablecoin market is not automatically a systemic risk. Concentration tells you how much of the market depends on a relatively small number of issuers. It does not, by itself, tell you how resilient those issuers are.
The exposure becomes more important when a large share of stablecoin supply sits with one or two issuers. In that situation, a disruption involving a major issuer can affect a meaningful portion of the market before other stablecoins have time or capacity to absorb the demand.
There is also a straightforward reason stablecoin markets tend to become concentrated. Liquidity attracts liquidity. The stablecoin accepted by the most exchanges, traders, payment providers, and applications is generally easier to use, which makes it more attractive to the next user as well.
Greater fragmentation could reduce concentration while also fragmenting liquidity and making settlement less efficient.
That is why concentration should be read alongside other stablecoin risk metrics. Peg stability, redemption pressure, liquidity, and reserve income provide information about resilience. Dominance and HHI tell you how large the exposure is.
Tether (USDT) holds approximately 60–65% of total stablecoin market cap. Because HHI weights by squared market share, a coin with 65% share contributes approximately 4,225 points to the index alone (0.65² × 10,000). USDT is therefore the largest single contributor to the current elevated HHI, with Circle's USDC and several emerging issuers also factored into the calculation.
Per-coin market share breakdown, the raw shares that drive the HHI score above.
How concentrated is USDT's supply on Tron? Chain-level concentration compounds issuer-level risk.
Early stress signal: concentrated markets amplify redemption cascades. Leading indicator for concentration-driven risk events.
Concentration becomes systemic when the largest issuers depeg. Peg stability tracks per-coin deviation from $1.00 with OHLC intraday data.
The aggregate scale that concentration applies to. HHI of $250B is materially different from HHI of $25B even at the same value.
The policy frame for why central banks watch concentration metrics. BIS's institutional thinking on stablecoin market structure.