For the first time, institutional and decentralized finance users can now swap between BlackRock’s tokenized U.S. Treasury fund, BUIDL, and Ethena’s USDtb stablecoin around the clock.
The new capability, announced by Securitize on June 18, marks a step forward in connecting traditional finance with DeFi. It sets a new standard for how tokenized assets are accessed and composed on-chain. Thanks to a new liquidity fund smart contract, qualified users onboarded through Securitize can now perform atomic swaps between BUIDL and USDtb around the clock.
As a result, holders of BUIDL, or BlackRock USD Institutional Digital Liquidity Fund, now have unlimited access to a variety of DeFi strategies that already incorporate USDtb. USDtb, which has a circulating supply of over $113 million, is primarily backed by BUIDL and offers a stable, composable, and yield-exposed dollar on-chain.
The integration was built by Securitize and Ethena (ENA) Labs, extending a partnership that began with the launch of the Converge blockchain in March this year. It enables asset holders to switch between programmable dollars and tokenized treasuries without the need for off-chain middlemen. This opens up new trading options and liquidity for both CeFi and DeFi participants.
BUIDL’s expanding role in crypto infrastructure is further demonstrated by its recent listing as collateral on Deribit and Crypto.com. The fund now dominates roughly 40% of the $7.3 billion tokenized U.S. Treasuries market, with strong inflows from institutions seeking regulated yield exposure.
At first, Ethena Labs held up to 90% of USDtb’s reserves in BUIDL but has since stopped making additional allocations. However, USDtb is still closely related to the liquidity and performance of the fund.
Systemic risks are introduced by the deep reserve concentration in BUIDL. If BUIDL were to face redemption bottlenecks or regulatory scrutiny, USDtb’s backing could be tested. However, with verified reserves and audited smart contracts, the system aims to balance transparency with capital efficiency.
