BUIDL is the BlackRock USD Institutional Digital Liquidity Fund, a tokenized money market fund issued by BlackRock and operated onchain through transfer agent Securitize. It launched on Ethereum on March 20, 2024, and now sits at roughly $3.0B in market cap as of June 5, 2026 (per the DeFiLlama stablecoin dashboard). Each BUIDL token targets a stable $1 value, accrues daily dividends from short-duration US Treasury bills, repo, and cash, and settles peer-to-peer between approved holders. It is the largest single tokenized Treasury product in a fast-growing category and has become a reference asset for institutional onchain cash management.
​

BUIDL is a Securities Act Rule 506(c) private fund managed by BlackRock Financial Management, with shares represented as ERC-20 tokens issued by Securitize Markets. Each token equals one share, priced at $1, with daily accrued yield paid monthly in additional BUIDL. BNY Mellon custodies the underlying Treasury bills, repo, and cash, while Securitize Financial Services acts as the transfer agent of record.
​

The fund is qualified-purchaser only and follows a standard 2a-7-style money market mandate, but the share register is maintained onchain rather than in a traditional book-entry system. BlackRock's product page describes the fund's investment objective and lists Securitize as the placement agent, custodian relationships, and subscription mechanics. Investors mint shares by wiring USD to the fund's bank account; Securitize then mints the corresponding token balance to a whitelisted wallet. Redemptions reverse the path, with USD wired out and tokens burned. For the canonical product overview, see the BlackRock BUIDL fund page. The fund's launch was announced on March 20, 2024, by BlackRock and Securitize.
​

BUIDL works as a permissioned ERC-20 token whose transfers are restricted to wallets that Securitize has KYC'd and added to the fund's whitelist. Dividends accrue daily based on the fund's net yield on Treasury bills, repo, and cash, and are distributed monthly as freshly minted BUIDL. Settlement is atomic and onchain, while subscriptions and redemptions clear offchain through wire transfer.
​

Mechanically, the fund operates as a two-sided system. The primary market is the mint and redeem channel between the investor's bank account and the fund's bank account at BNY Mellon, intermediated by Securitize as transfer agent. The secondary market is the onchain transfer of BUIDL tokens between whitelisted wallets, which avoids the standard T+1 settlement window for fund shares. Token logic enforces the whitelist at the contract level, so a transfer to a non-approved wallet reverts. Holders can therefore use BUIDL as a near-cash settlement leg in onchain transactions without exiting the fund. For technical context on the tokenized Treasury category and live issuance data, see the rwa.xyz tokenized Treasuries dashboard.
​

BUIDL is restricted to qualified purchasers under section 2(a)(51) of the Investment Company Act, with a $5 million minimum initial subscription. Buyers must complete Securitize's KYC, KYB, and accreditation review, sign the fund's subscription documents, and have the receiving wallet added to BlackRock and Securitize's onchain whitelist before any tokens can be minted to that address.
​

In practice, the qualified-purchaser bar means most BUIDL holders are asset managers, treasuries of crypto-native companies, market makers, and tokenization issuers that need a yield-bearing cash leg. The mint access process is run by Securitize as the SEC-registered transfer agent and broker-dealer, with BlackRock acting as investment manager. Holders can hold BUIDL self-custodied at Anchorage, Coinbase Custody, Fireblocks, BitGo, Komainu, Copper, or in their own multisig, provided the wallet is whitelisted. BlackRock's fund page lists current eligibility and minimum requirements, which can change at the manager's discretion.
​

BUIDL is a registered money market fund that pays yield to holders; USDC and USDT are non-yielding payment stablecoins issued under reserve-backing models rather than fund structures. BUIDL distributes income, restricts transfers to whitelisted wallets, and reports under securities law. USDC and USDT trade freely on any wallet and are designed for high-velocity payments rather than treasury management.
​

The practical contrast shows up in three dimensions: investor base, yield treatment, and transferability. USDT, issued by Tether, sits at roughly $187.2B in supply, and USDC, issued by Circle, sits at $75.6B, against a total stablecoin market of $315.3B as of June 5, 2026 (DeFiLlama). BUIDL, at $3.0B, is two orders of magnitude smaller but is the dominant tokenized money market fund. For users who want exposure to yield without the qualified-purchaser bar, secondary wrappers like Ondo Finance's OUSG and Ethena's USDtb hold BUIDL as collateral and pass on yield in different forms.

BUIDL launched on Ethereum mainnet on March 20, 2024, and expanded in November 2024 to Aptos, Arbitrum, Avalanche, Optimism, and Polygon. Each deployment is a separate Securitize-controlled ERC-20 (or Aptos-native equivalent) tied to the same fund, and inter-chain movement of shares is intermediated by Securitize rather than by an open bridge.
​

The multi-chain expansion was announced by Securitize on November 13, 2024 and broadened BUIDL's reach to networks where institutional counterparties, prime brokers, and DeFi protocols already hold meaningful balances. Ethereum remains the dominant venue by share, and chain selection is generally driven by where a holder's counterparty wants to settle. Holders can move BUIDL across supported chains through Securitize's transfer agent process, which keeps the share register consistent across deployments. For the breakdown of supply by chain and current issuance, see the DeFiLlama BUIDL page, and for the original chain expansion announcement, see the Securitize press archive.
​

BUIDL matters because it gave the tokenized real-world asset market its first credible reference product from a Tier 1 asset manager. By Q1 2025 the tokenized US Treasuries category had surpassed $7B (per rwa.xyz), with BUIDL anchoring institutional flows. Its existence pulled the rest of the RWA stack, from custodians to settlement venues to data providers, toward production-grade infrastructure.
​

The downstream effect is that other issuers can launch tokenized funds against an existing institutional reference. Franklin Templeton's BENJI, WisdomTree's WTGXX, Ondo's OUSG and USDY, Superstate's USTB, and Hashnote's USYC all operate in the same neighborhood and benefit from the standards, custody integrations, and KYC pipelines that BlackRock and Securitize hardened. BUIDL also created a credible answer to the question of where idle onchain cash should sit, which had previously bounced between USDC and DAI for institutional balance sheets. The result is a tokenized money market that is now structurally adjacent to the $315.3B stablecoin market rather than separate from it.
​

BUIDL's onchain role splits into three uses: collateral inside other tokenized products, settlement asset between institutional counterparties, and yield pass-through for retail-facing wrappers. Because the token is permissioned, it does not appear directly in open DeFi pools, but it underpins several open products through holding entities like Ondo Finance and Ethena.
​

Ondo's OUSG redirected its underlying holdings into BUIDL in 2024, using the fund as the yield-bearing leg behind an institutional Treasury token. Ethena's USDtb is backed primarily by BUIDL and circulates as a $1.1B stablecoin on open markets. On the settlement side, BUIDL gives counterparties a way to clear large positions in a yield-bearing instrument without leaving onchain rails, which compresses opportunity cost relative to parking idle USDC. As a neutral aggregator of stablecoin and tokenized cash liquidity, Eco Routes treats BUIDL-backed assets like USDtb and OUSG as first-class stablecoin endpoints alongside USDC and USDT, with Hyperlane as the live cross-chain rail and CCTP as internal transport for native USDC movement. For live composition and holder data, see rwa.xyz.
​

BUIDL is the first large-scale tokenized money market fund from a Tier 1 asset manager, and it has become the reference point for institutional onchain cash. At $3.0B in supply on six chains, it sits at the intersection of regulated fund structure, onchain settlement, and the broader $315.3B stablecoin market. For institutional buyers it is mint access to BlackRock-managed Treasury exposure with onchain transfer rights; for the rest of the market it is the collateral asset that quietly underpins a growing slice of yield-bearing stablecoins and tokenized Treasury wrappers.
​

The category is still early. Tokenized Treasuries remain a small slice of the stablecoin float and a rounding error against the multi-trillion-dollar money market fund industry. As more issuers list, more chains support permissioned share classes, and more orchestration layers route yield-bearing cash across markets, BUIDL's role as the anchor of the tokenized Treasury market is likely to compound rather than fade. For ongoing tracking, the DeFiLlama BUIDL dashboard and the rwa.xyz Treasuries page remain the two most useful primary sources.
​

Methodology: stablecoin supplies and BUIDL market cap pulled from DeFiLlama on June 5, 2026. Tokenized Treasury totals reference rwa.xyz Q1 2025 data. Launch and chain expansion dates reference primary announcements from BlackRock and Securitize.
​