BUIDL is the BlackRock USD Institutional Digital Liquidity Fund, a tokenized money market fund launched in March 2024 with Securitize as transfer agent. As of May 2026, BUIDL holds approximately $2.5B in assets under management across six chains, making it one of the two largest tokenized US Treasury products alongside Circle's USYC tracked by rwa.xyz. Yield flows from US Treasury bills, repurchase agreements, and cash held by BNY Mellon.
​

BUIDL is a tokenized money market fund issued by BlackRock and administered by Securitize, representing fractional ownership of a portfolio of short-duration US government securities. Each BUIDL token targets a stable $1 net asset value and accrues yield daily via a rebase mechanism. The fund is restricted to qualified purchasers with a $5M minimum subscription.
​

The fund's legal wrapper is a British Virgin Islands professional fund, registered under Regulation D Rule 506(c) for accredited US distribution. Securitize serves as transfer agent and broker-dealer, handling subscriptions, redemptions, and the KYC pipeline. BNY Mellon custodies the underlying Treasury holdings. BlackRock manages the portfolio under its existing money market fund mandate.
​

The product is positioned as the first major incumbent asset manager bringing a flagship cash-management strategy onchain. Before BUIDL, the tokenized Treasury category was dominated by crypto-native issuers like Ondo, Franklin Templeton's BENJI, and Matrixport's STBT. BlackRock's entry in March 2024 reframed tokenized Treasuries as institutional infrastructure rather than a niche product. Within six months, BUIDL crossed $500M in AUM, and by Q1 2025 it had passed $1B. The May 2026 figure of approximately $2.5B reflects continued institutional demand for onchain yield with familiar issuer credit.
​

BUIDL generates yield by holding a portfolio of US Treasury bills, overnight repurchase agreements, and operating cash. Interest accrues daily and is distributed monthly as new BUIDL tokens to each holder's wallet, preserving the $1 NAV target. The underlying basket targets the secured overnight financing rate as a benchmark.
​

The portfolio is constructed for capital preservation and intraday liquidity. Treasury bills with maturities under 90 days form the bulk of holdings, repos cover short-term cash needs, and a cash buffer at BNY Mellon supports redemption windows. The fund's prospectus filed with the SEC details the eligible instrument list and the daily NAV calculation. Daily mark-to-market is published by Securitize and reflected onchain through the rebase event.
​

Distribution mechanics matter for downstream protocols. Because yield is paid as additional tokens rather than a price drift on a single share, BUIDL behaves like a rebasing stablecoin from an integrator's perspective. Wallets holding BUIDL see their balance increase monthly without any user action. Protocols that want to wrap BUIDL into a non-rebasing derivative must track the accrual and adjust the wrapper's exchange rate accordingly. Ondo's OUSG and Securitize's own sToken wrappers handle this conversion for downstream consumers who prefer a fixed-supply, appreciating-NAV token.
​

Effective yield tracks short-term Treasury rates closely. In Q1 2026, BUIDL's distributed yield ran in the low 4% range annualized, reflecting the prevailing federal funds rate and the term structure of the fund's underlying holdings. The yield is published by Securitize on the fund's institutional portal; protocols and treasuries that integrate BUIDL pull the rate from that disclosure rather than estimating it.
​

BUIDL deployed first on Ethereum in March 2024, then expanded to Aptos, Polygon, Optimism, Arbitrum, and Avalanche through 2024 and 2025. Each deployment maintains the same share class and NAV; cross-chain holdings net at the fund level rather than at the token level. Total supply across chains is published by rwa.xyz.
​

The ERC-20 contract enforces an allow-list at the token level. Transfers to non-whitelisted addresses revert, which is the mechanism that keeps the fund compliant with Reg D Rule 506(c) and KYC obligations across deployments.
​

BUIDL is restricted to qualified purchasers as defined by the US Investment Company Act, which generally means individuals with at least $5M in investments or institutions with at least $25M. The minimum subscription is $5M, set at the fund level. KYC, AML, and accreditation are processed through Securitize before any wallet is added to the allow-list.
​

Qualified purchaser status is higher than the accredited investor threshold that gates retail-facing tokenized products like USDY. The $5M minimum and qualified purchaser gate together make BUIDL an institutional product in practice. Corporate treasuries, crypto-native funds, and stablecoin issuers are the primary holder base. Ondo Finance disclosed in 2024 that OUSG holds a substantial BUIDL position as part of its underlying basket, and Circle has reported BUIDL exposure in its reserve mix at points during 2024 and 2025.
​

The onboarding process flows through Securitize's institutional portal. A prospective subscriber completes a Form W-9 or W-8BEN-E, supplies qualified purchaser verification documents, runs KYC and AML checks, and signs the subscription agreement. Securitize then whitelists a designated wallet address. The wallet can be a self-custody address controlled by the institution, a Fireblocks vault, an Anchorage Digital account, or a BitGo institutional custody account. Once whitelisted, the subscriber wires USD to the fund's bank, and Securitize mints BUIDL to the whitelisted wallet at the next NAV strike. End-to-end onboarding typically runs five to ten business days depending on the institution's existing KYC posture.
​

BUIDL is one of the two largest tokenized Treasury funds by AUM (alongside Circle's USYC) but not the most accessible. Compared with Ondo OUSG, Franklin Templeton BENJI, Superstate USTB, and Hashnote USYC, BUIDL has the highest minimum, the most chains, and the BlackRock brand. The other funds vary on minimum, retail access, and onchain composability.
​

The comparison shows BUIDL's positioning. The fund optimizes for institutional credibility and multi-chain reach rather than retail access. Funds like BENJI take the opposite approach, registered under the Investment Company Act of 1940 to allow retail purchases through Franklin Templeton's app. rwa.xyz publishes side-by-side AUM and chain coverage for all six funds.
​

BUIDL tokens are held in whitelisted wallets approved by Securitize, which can be self-custody wallets, Fireblocks vaults, Anchorage Digital accounts, or BitGo institutional custody. Transfers between BUIDL holders are permitted within the allow-list; transfers to non-whitelisted addresses revert at the contract level. Redemptions to USD are settled by Securitize within standard T+0 or T+1 windows.
​

The permissioned ERC-20 pattern is enforced through a registry contract that Securitize maintains. Every transfer checks the registry; addresses removed from the allow-list cannot receive or send BUIDL. This is a different model from public stablecoins like USDC, where transfers are permissionless and only freeze-list addresses are blocked. The permissioning is what allows BlackRock to satisfy the qualified purchaser and KYC obligations while still using a public chain for settlement.
​

Redemption flows are equally controlled. A holder submits a redemption request through Securitize's portal, the corresponding BUIDL tokens are burned at the next NAV strike, and Securitize wires USD to the holder's bank account. For institutions that need same-day liquidity outside of regular fund redemption windows, Circle and Ondo have at points offered secondary-market BUIDL-to-stablecoin swaps, which give holders an instant exit at a small discount to NAV. These third-party windows are not part of BlackRock's official redemption mechanism but have improved BUIDL's intraday liquidity profile for downstream protocols.
​

BUIDL functions as a yield-bearing reserve asset for crypto-native institutions that need US Treasury exposure with onchain settlement. Ondo Finance uses BUIDL as part of OUSG's underlying basket. Frax Finance and other stablecoin issuers have explored BUIDL as a reserve component. The fund acts as a bridge between BlackRock's traditional asset management franchise and onchain markets.
​

The integration pattern is straightforward. A protocol holds BUIDL in a whitelisted vault, mints a derivative token against that holding, and distributes the yield to derivative holders. OUSG works this way. Some perp DEXes accept BUIDL as collateral for the same reason: it generates yield while sitting in margin, which improves capital efficiency. As more institutional treasuries hold BUIDL alongside USDC and USDT, the fund becomes the institutional anchor for the broader tokenized cash market.
​

The market structure implications run deeper than collateral. Stablecoin issuers face an obvious question. If BUIDL pays roughly 4% to its holders while USDC and USDT pay nothing to theirs, why would an institution park idle treasury in a non-yielding stablecoin? In practice, most institutions hold a mix. USDC for working capital that needs to move daily across chains and counterparties. BUIDL for the strategic reserve that can sit for weeks. This split has been visible in stablecoin issuer reserve disclosures and in onchain wallet flows tracked by analytics firms. The tokenized Treasury category, with BUIDL at its center, is becoming the onchain equivalent of a money market fund sweep account for crypto-native balance sheets.
​

BUIDL holders take on the credit risk of the underlying Treasury portfolio, operational risk through Securitize as transfer agent, smart contract risk on the permissioned ERC-20 deployments, and legal risk from the BVI fund wrapper. None of these is unique to BUIDL, but each is worth pricing into the decision versus a comparable offchain money market fund.
​

Credit risk on the underlying portfolio is minimal given the short-duration Treasury composition, though the fund is not FDIC-insured and the cash buffer at BNY Mellon is subject to standard bank counterparty risk above insured limits. Smart contract risk is concentrated in the permissioned ERC-20 contracts and the registry contract that gates transfers; an exploit of the registry could in principle freeze or misroute holdings, though no such incident has been reported. Operational risk through Securitize covers the KYC pipeline, the daily NAV publication, and the redemption window administration.
​

The BVI fund wrapper sits outside the US Investment Company Act, which is a different legal posture from Franklin Templeton's BENJI, registered under the 1940 Act for retail distribution. Institutions weighing BUIDL against BENJI or against an offchain money market fund typically run a tradeoff matrix on yield, accessibility, redemption mechanics, and legal wrapper before committing capital. The matrix usually comes out favoring BUIDL for crypto-native institutions that already use multi-chain infrastructure and need a yield-bearing asset that can settle in the same block as their existing stablecoin positions. Traditional institutions that already hold offchain money market funds and have no near-term need for onchain settlement often stick with their existing vehicles.
​

Eco Routes does not custody or distribute BUIDL. Where Eco fits the tokenized Treasury market is settlement of the surrounding stablecoin flows. Institutional desks subscribing to or redeeming BUIDL move USDC across Ethereum, Optimism, Arbitrum, and Polygon to fund or receive proceeds; Eco Routes settles those USDC transfers across the six BUIDL-supported chains in one transaction.
​

Eco's role is the cross-chain stablecoin plumbing rather than the fund itself. A trading desk that holds BUIDL on Ethereum but needs to fund a USDC obligation on Arbitrum runs that transfer through Eco Routes. The BUIDL holding remains in its whitelisted vault; only the working-capital stablecoin moves. The same pattern applies in reverse for subscriptions: a desk that wants to convert USDC on Optimism into BUIDL must first consolidate stablecoin liquidity to Ethereum, where Securitize accepts USD wire transfers from converted USDC, then complete the subscription. Eco Routes compresses that consolidation step into a single transaction across the six BUIDL-supported chains.
​

Top tokenized treasury funds
​

Ondo USDY explained
​

YLDS on Stellar yield-bearing stablecoin
​

Paxos white-label stablecoin platform
​

Sources and methodology. AUM and chain-deployment data pulled from rwa.xyz in May 2026. Fund structure verified against the Securitize launch announcement and the BusinessWire press release. AUM figures refresh weekly and may move between publication and reading.
​