PRIM3 Brief #10: Stablecoin Issuer Concentration — The Hedge Nobody's Buying

The on-chain dollar market is dominated by two issuers. As of early May 2026, Tether (USDT) and Circle (USDC) together account for roughly 88% of the global stablecoin supply, about $260B of an aggregate $295B market, per CoinGecko and DefiLlama. Sky/USDS, Ethena's USDe, Frax, the second-tier yield-bearing issuers, and the wave of new RWA-backed entrants split the remaining 12%.

This concentration ratio is the largest in stablecoin history. It's also, by our reading, the single largest systemic-risk concentration sitting inside Web3 infrastructure today, and one that is meaningfully underpriced by institutional participants. PRIM3 has been having this conversation in private with portfolio companies and LPs for the past 90 days. We're making it public because we think the broader market would benefit from the framing.

The Concentration In Context

Two-issuer dominance of a financial primitive isn't, by itself, unusual. Visa and Mastercard together account for the majority of card payment volume globally. Two reinsurers handle a significant share of the global reinsurance market. The two largest CSDs handle most of the developed-world securities settlement. Concentration is a feature, not a bug, of mature financial infrastructure.

What's specifically concerning about the USDT-USDC concentration in 2026 is the combination of three factors that don't apply to the traditional comparators.

First, the reserve composition. Both issuers hold predominantly short-duration Treasury bills and tokenized MMF exposure. That's fundamentally sound but it concentrates the underlying reserve risk in a single asset class. A meaningful disruption to short-duration Treasury markets — which we don't expect, but which the historical record can't rule out over a 36-month horizon, would affect both issuers simultaneously.

Second, the lack of jurisdictional diversification. Tether is operationally based in the British Virgin Islands and El Salvador; Circle is U.S.-domiciled. That jurisdictional separation provides some diversification, but the underlying reserve assets are predominantly U.S. dollar-denominated and U.S. Treasury-backed. A U.S.-specific shock affects both.

Third, the absence of credible substitutes at the institutional scale. The third-largest stablecoin, Sky's USDS, sits at roughly $9B AUM, an order of magnitude smaller than the two leaders. And a flight-from-USDT-and-USDC event in size has no place to land at institutional scale. The institutional flow would have to either exit on-chain dollars entirely or accept the operational complexity of distributing into a fragmented set of smaller issuers.

The aggregate exposure is, in our view, comparable to the 2022–2023 regional-banking crisis in magnitude — except that the on-chain ecosystem has fewer Federal Reserve-style backstops if it materialises.

The Specific Mechanisms That Worry Us

A few scenarios PRIM3 has been modelling internally for portfolio companies:

Scenario one: a regulatory enforcement action against one of the two issuers. Not a hypothetical, the 2025 settlement between Tether and a U.S. agency over historical disclosure issues is one example of how this can materialise. A more aggressive future action that forced operational changes mid-cycle could produce significant volatility. The market handled the 2025 Tether settlement gracefully. There's no reason to believe a more aggressive future action would be handled with equivalent grace.

Scenario two: a reserve-attestation disclosure that surfaces a material issue. Both issuers have improved their reserve attestation substantially since 2022. The gap between current attestation and full GAAP-grade audit is, in some areas, still material. A finding that surfaced during a reserve audit could create a confidence shock disproportionate to the actual financial issue.

Scenario three: a CBDC or central-bank-led action that explicitly disadvantages private USD stablecoins. Less likely under the current U.S. administration, but the EU's stance on private stablecoin issuance under MiCAR is markedly less permissive than the U.S. approach. A coordinated international stance against private-USD-stablecoin issuance would force material restructuring.

Scenario four: an operational incident at one of the two — a banking partner failure, a smart contract issue at a related infrastructure layer, a settlement delay. Lower probability per event but the cumulative probability over 24 months is non-trivial.

None of these scenarios is base-case for PRIM3. The point isn't to predict any specific one. The point is that the institutional cohort is collectively running a position size against the joint distribution of these scenarios that is much larger than what would be considered prudent in any traditional portfolio context.

Why The Institutional Cohort Isn't Hedged

Here's the puzzle. The institutional cohort — multi-strategy hedge funds, family offices running serious crypto exposure, the sophisticated DeFi operators — is collectively running enormous net exposure to USDT and USDC. The aggregate hedging activity against that exposure is, by our tracking, less than 5% of what an equivalent position size in traditional finance would carry.

Why? A few reasons.

First, the on-chain hedging instruments are immature. There are some credible options on USDT/USDC, but the depth and tenor available don't match what an institutional treasurer would expect for traditional fiat exposure. Deribit and the second-tier options venues have made progress, but the surface for hedging a $500M USDT position cleanly is genuinely limited in 2026.

Second, the hedging cost is unattractive. When you can buy direct treasury exposure at 4%+ and the credible USD stablecoins are paying 0%, the carry cost of holding the stablecoin already includes a meaningful implicit risk premium. Adding explicit hedging on top is hard to justify on a return-adjusted basis.

Third, and this is the part PRIM3 thinks is genuinely mispriced, the institutional cohort has internalised the assumption that "USDT and USDC are too big to fail." That's the same assumption that produced the 2022–2023 banking sector exposure to a small set of mid-sized regional banks, with the well-known result. The "too big to fail" framing was wrong then and is, in our view, wrong now.

What We're Telling Portfolio Companies

For portfolio companies running significant stablecoin treasury balances:

Diversify across issuers actively. A treasury that holds 50% USDC + 30% USDT + 20% in the third-tier issuers (Sky, USDe, a yield-bearing MMF position) is substantially less concentrated than a treasury that holds 80% USDC + 20% USDT. The operational cost of the diversification is modest. The risk-adjusted improvement is meaningful.

Hold a portion in tokenized treasury or MMF positions directly. A position in BUIDL, OUSG, or an equivalent tokenized treasury product is closer to the underlying risk than a position in a stablecoin issuer is. The redemption mechanics are slightly slower but the issuer-specific risk is removed.

Maintain off-chain dollar exposure for operational reserves. A small share of treasury (10–20%) held in a traditional banking relationship denominated in fiat USD provides hedge against the scenario where on-chain stablecoin functionality is disrupted entirely. This sounds obvious but a non-trivial share of crypto-native organisations don't currently maintain this.

Use credible options hedging at scale. For organisations with $100M+ in stablecoin treasury, the marginal cost of layering options-based hedging on the USDT and USDC tranches is now low enough relative to the position size to be justified. Speak to the credible options desks (Deribit, the institutional OTC providers, the better DeFi-native options venues) about structuring.

Where We're Allocating

PRIM3 is actively looking for credible third-tier stablecoin entrants that can take meaningful share from USDT and USDC over the next 36 months. The market needs more credible alternatives, and we think the regulatory framework (per PRIM3 Brief #6 and Brief #9) is becoming more favourable to credible institutional entrants. We're also looking at infrastructure that makes stablecoin diversification operationally simpler — auto-rebalancing treasury tooling, multi-issuer redemption rails, hedging-as-a-service products for crypto-native treasurers.

If you're building credibly in any of these segments, we'd be interested. Pitch us via prim3.vc.