How Tokenized US Treasuries Actually Work: BUIDL, Ondo, and What You're Really Holding

Most guides tell you tokenized Treasuries "put US government bonds on-chain." That framing is wrong in a way that matters. No T-bill lives on Ethereum. What lives on-chain is a token representing a share in a legal entity that holds Treasuries through a traditional custody chain. The difference between those two things is exactly where the risk lives — and where the yield actually comes from. This guide closes that gap.

When you hold a token like BUIDL (BlackRock USD Institutional Digital Liquidity Fund), you don't hold a fractionalized Treasury bond. You hold a share in a BVI-domiciled fund managed by BlackRock Financial Management. That fund buys short-duration US Treasuries, repos, and cash through Bank of New York Mellon as custodian. The ERC-20 token on Ethereum is a digital representation of your fund share — functionally closer to a money market fund share than to a bond.

This matters because your counterparty risk isn't the US government. It's the legal structure around the fund: the fund administrator (PwC), the custodian (BNY Mellon), and the transfer agent (Securitize). If Securitize's infrastructure goes down, your on-chain token still exists, but minting and redeeming new shares stops. The token is the receipt, not the asset.

Ondo Finance's OUSG works similarly but adds a layer: OUSG holds shares in BlackRock's SHV ETF (iShares Short Treasury Bond ETF), not Treasuries directly. So OUSG holders are tokenizing exposure to an ETF that holds Treasuries — two levels of indirection. Ondo's USDY is structured differently: it's a bankruptcy-remote senior secured note issued by Ondo Finance, backed by a portfolio of short-term Treasuries and bank deposits. Legally, USDY is a debt instrument, not a fund share.

⚠ Common mistake: Treating all tokenized Treasury products as equivalent. BUIDL is a fund share, USDY is a secured note, and stUSDT (on Tron, managed by RWA DAO with JustLend) wraps TrueUSD's reserves. These have completely different legal claims, redemption paths, and risk profiles.

The standard explanation says these tokens "pass through Treasury yield." What's actually happening varies by product. BUIDL accrues yield daily and distributes it by minting new tokens to holders on the last business day of each month — your token count increases, but each token targets a $1.00 NAV. At roughly 4.5–5.0% APY (fluctuating with the fed funds rate as of mid-2025), a $1M BUIDL position mints approximately 3,750–4,166 new tokens per month.

OUSG handles it differently: the token itself is rebasing, meaning the price per token rises to reflect accumulated yield rather than minting new tokens. USDY also appreciates in price — it launched around $1.00 in mid-2023 and trades above $1.05 as of mid-2025, reflecting accumulated yield baked into the token price.

Fund-level expenses eat into the gross Treasury rate. BUIDL charges a 0.20% management fee (previously 0.50%, reduced in early 2025). Ondo charges 0.15% on OUSG. The on-chain yield you receive is the net rate after these fees and after the fund's operating costs. When you see a tokenized Treasury product advertising a higher rate than the underlying T-bill, that's a red flag — the product may be taking duration or credit risk beyond short-term Treasuries.

⚠ Common mistake: Assuming yield appears automatically in your wallet with no tax event. Each rebase or token mint is likely a taxable event in most jurisdictions. The IRS hasn't issued specific guidance on rebasing RWA tokens, but the conservative interpretation treats each accrual as ordinary income.

BUIDL is restricted to qualified purchasers under US securities law — generally institutions or individuals with $5M+ in investments. Securitize acts as the transfer agent and enforces a whitelist: only addresses that have passed KYC/AML through Securitize's identity platform can receive BUIDL tokens. If you try to transfer BUIDL to a non-whitelisted address, the transaction reverts on-chain. The token contract enforces this at the smart contract level.

OUSG has similar restrictions (accredited investors, $50K minimum via Ondo's interface). USDY is more accessible — Ondo specifically structured it to avoid US securities registration requirements for non-US persons, meaning non-US holders can buy USDY without accredited investor status. US persons are excluded from USDY.

This creates a two-tier market. Institutional products like BUIDL are used primarily as collateral or treasury management by DAOs and protocols (Sky/Maker holds over $1B in BUIDL as backing for DAI). Retail-accessible products like USDY and Mountain Protocol's USDM serve DeFi users who want yield-bearing stablecoin alternatives.

⚠ Common mistake: Buying a tokenized Treasury wrapper on a DEX and assuming you have the same legal protections as a direct holder. Secondary market purchases of tokens that require whitelisting (like BUIDL or OUSG) won't settle — the transfer will revert. For products tradable on DEXs (like USDY), you hold the token but may not have direct redemption rights without completing KYC with the issuer.

As of mid-2025, tokenized US Treasuries collectively hold over $6 billion in total value locked. The market is concentrated:

• BUIDL (BlackRock/Securitize): Over $2.8B AUM, deployed across Ethereum, Arbitrum, Avalanche, Optimism, Polygon, and Aptos. The largest single tokenized Treasury product.
• USDY (Ondo Finance): Approximately $600M+ AUM. Available on Ethereum, Solana, Mantle, Sui, Aptos, and others. The most broadly available across L1s and L2s.
• OUSG (Ondo Finance): Around $500M+, primarily on Ethereum. Higher minimum, institutional focus.
• USDM (Mountain Protocol): Roughly $100M+, ERC-20 rebasing stablecoin backed by short-term Treasuries. Targets the "yield-bearing stablecoin" niche.
• USDS/sUSDS (Sky/Maker): Not a direct tokenized Treasury, but Sky's allocation to Treasuries (through BUIDL and direct holdings) means sUSDS yield partially derives from T-bill exposure.
• stUSDT: Over $1B on Tron, managed by JustLend/RWA DAO. Less transparent on reserve verification than Ethereum-based alternatives.
• Hashnote USYC: Over $1B, primarily used as institutional collateral and integrated into DeFi through partnerships.

Franklin Templeton's BENJI (FOBXX) was an early mover — a registered fund using Stellar and Polygon — but its AUM (~$500M+) has been eclipsed by BUIDL's rapid growth.

⚠ Common mistake: Comparing these products by APY alone. The relevant differences are legal structure, redemption speed, chain availability, composability in DeFi, and minimum investment. A product with 0.1% higher yield but a 5-day redemption window and no DeFi integrations serves a completely different use case than one with instant DEX liquidity.

Here's where tokenization reveals its limits. Minting and burning BUIDL shares happens through Securitize during business hours. You submit a redemption request, Securitize processes it, the fund sells the underlying Treasuries (or uses cash reserves), and USDC is sent to your whitelisted wallet. Standard settlement is T+0 to T+1 for BUIDL, thanks to a $100M+ USDC liquidity facility provided by Circle that enables same-day redemptions up to a threshold.

But this instant redemption has a ceiling. If redemptions exceed the USDC facility's capacity, you're back to traditional fund redemption timelines — potentially T+1 to T+3 depending on the underlying assets' settlement. During a market stress event where everyone wants out simultaneously, that buffer matters enormously.

OUSG redemptions process through Ondo's interface, typically T+1 to T+2. USDY has DEX liquidity on some chains, so you can sell on-chain without going through the issuer — but at whatever price the market offers, which may be below NAV during volatility.

⚠ Common mistake: Assuming on-chain tokens mean instant, 24/7 liquidity. The token transfers 24/7, but minting, redeeming, and NAV calculations follow traditional finance schedules. Weekends and US holidays mean no new mints or redemptions for BUIDL, even though the token itself is tradeable on-chain.

You don't have to trust marketing pages. Use these tools:

• BUIDL token contract on Ethereum: Search the token on Etherscan (0x7712c34205737192402172409a8F7ccef8aA2AEc) to see holder count, transfer restrictions, and total supply. Cross-reference with Securitize's fund reporting.
• DeFiLlama RWA dashboard: defillama.com tracks tokenized Treasury TVL across products and chains. The "RWA" category page breaks down AUM by protocol.
• Ondo Finance dashboard: ondo.finance publishes daily NAV, AUM, and reserve composition for OUSG and USDY.
• Dune Analytics: Multiple community dashboards track BUIDL AUM growth, holder distribution, and mint/redeem volume. Search "BUIDL" or "tokenized treasuries" on Dune.
• rwa.xyz: A third-party aggregator tracking most tokenized Treasury issuers with daily AUM updates and yield comparisons.

When checking, compare the on-chain token supply multiplied by the stated NAV against the issuer's reported AUM. If those numbers diverge meaningfully, something needs explaining.

• Read the legal documents. BUIDL's offering memorandum (via Securitize) and Ondo's USDY token documentation spell out exactly what you hold, what the redemption terms are, and where the risk sits. These are securities — treat them like it.
• Track the BUIDL USDC redemption facility. Circle's liquidity buffer for instant BUIDL redemptions is a critical piece of infrastructure. Monitor its size relative to BUIDL's growing AUM — if AUM grows 10x but the buffer doesn't, instant redemption breaks down.
• Explore DeFi composability. BUIDL and USDY are increasingly used as collateral in lending protocols and as backing for stablecoins. Understanding how Maker/Sky uses BUIDL to back DAI gives you insight into how traditional yield flows into DeFi — that's a separate guide-level topic.
• Compare with direct T-bill access. TreasuryDirect.gov lets US persons buy T-bills directly with no fees. If you're a US individual just wanting yield, understand what tokenization adds (composability, collateral use) versus what it costs (fees, counterparty risk, tax complexity).