Ethena USDtb vs Frax USD: reserves and risk (2026)

Both are Ethereum stablecoins with on-chain minting and redemption, but their reserve descriptions differ. USDtb’s reserves are invested in short-duration treasury assets through BlackRock’s BUIDL tokenized fund, which holds cash, Treasury bills and notes. This gives USDtb a specific named fund and service providers, but also concentrates reserve exposure and adds dependence on third parties.

Frax USD is described as fully collateralized by cash-equivalent reserves held with off-chain custodians. Its backing model is presented more simply, but the custodians are not named. That leaves users with less detail here about who holds the reserves. Neither design removes issuer, counterparty, redemption or smart-contract risk.

USDtb has about $417.2 million in TVL, compared with about $99.1 million for Frax USD. USDtb is described as available for on-chain minting and redemption at any time of day, and as composable across DeFi, including Aave, Morpho, Euler and Fluid. It is also listed as collateral on centralized exchanges and prime-broking venues, including Bybit.

Frax USD also has on-chain minting and redemption, but the listed details do not name specific integrations beyond its place in the Frax ecosystem. That makes USDtb the clearer fit if you want named money-market or exchange-collateral use. TVL is a measure of reported usage, not a guarantee of liquidity, stability or redemption access. Check current terms and availability before relying on either token for a particular use.

Neither project publishes mint or redemption fees in these details. USDtb’s fee information is not stated, and Frax USD’s fees, spreads and redemption limits are not published. Check the relevant mint or redemption interface and current project documentation before transacting, since terms may apply at the time of use.

Both are listed on Ethereum, so ordinary Ethereum network gas costs may apply when transferring or interacting with the tokens. If you swap either token through a decentralized exchange, the venue may charge trading fees and the trade may incur slippage. Those costs are separate from any issuer mint or redemption charges. Do not assume that either stablecoin is free to mint, redeem or transfer simply because a fee schedule is not stated here.

Frax USD has two audits listed, but their scope, auditors and findings are not detailed. USDtb has no audits listed, despite homepage claims about audits; the firms and reports are not identified. For both projects, an audit count alone does not establish that every contract or risk has been reviewed.

USDtb’s reserve safety depends on BUIDL and providers including Securitize and BNY Mellon. BUIDL transfers are restricted to whitelisted investors, so reserve access is subject to KYC/AML rules. Frax USD also depends on off-chain custodians, whose names and reserve attestations are not published here. Both carry smart-contract, redemption and depeg risks. USDtb’s planned path toward a federally regulated payment stablecoin is a stated plan, not confirmation of that status today.

Choose USDtb if you value a named treasury-fund reserve structure, the described 24/7 mint-and-redeem mechanism, or its named DeFi and exchange-collateral integrations. Its higher reported TVL may also matter if you are comparing current scale, but it does not guarantee that you can redeem at a particular time or price. Consider its concentration in BUIDL, whitelisting constraints and reliance on several service providers.

Choose Frax USD if you prefer a straightforward description of full cash-equivalent collateralization and want a token with two listed audits. Be aware that the custodians are not named and the audit details are not provided. For either option, verify redemption terms, reserve disclosures, fees and the current status of integrations before using it. Neither stablecoin is risk-free.