USDtb is a fully-reserved stablecoin issued by Ethena Labs, built to sit alongside — and backstop — the same company's derivatives-hedged USDe, but backed almost entirely by BlackRock's tokenised US Treasury fund rather than staking yield and perpetual futures.
What it does
Launched in late 2024 in partnership with Securitize, USDtb's reserves are mostly held in BUIDL, BlackRock's USD Institutional Digital Liquidity Fund, which itself invests in cash, US Treasury bills and repurchase agreements. That makes USDtb structurally closer to a traditional fiat-backed stablecoin like USDC than to its sibling USDe, whose value depends on a delta-neutral hedge holding up.
Ethena uses USDtb as part of USDe's reserve fund — a buffer that can absorb losses if funding rates on USDe's hedges turn negative for an extended stretch — and DeFi protocols such as Morpho and Term Finance have integrated USDtb directly as a lending and collateral asset, drawn by its Treasury-grade backing and Ethena's distribution reach.
Risks
USDtb's safety is only as good as its dependencies: it relies on BlackRock and Securitize's BUIDL infrastructure, meaning redemption mechanics, eligibility rules and any operational hiccup at that layer flow straight through to USDtb holders. It is newer and far smaller than USDC or USDT, so liquidity and exchange support are still developing.
Its close coupling to Ethena — a protocol running a much riskier, higher-yield product in USDe — means reputational or operational trouble at Ethena Labs could spill over into USDtb even though the token's own backing is more conservative. As with any tokenised fund wrapper, holders are trusting two organisations' operational integrity — BlackRock/Securitize on the reserve side, Ethena Labs on the token and smart-contract side — rather than one issuer end to end.