USD0 Savings (sUSD0)
sUSD0 is the savings token for USD0, implemented as a non-rebasing ERC-4626 vault. It turns USD0 from a settlement stablecoin into a yield-accruing savings instrument that is composable, transparent, and fully on-chain.
Users deposit USD0 into a permissionless vault and receive sUSD0 shares in return. sUSD0 balances do not rebase; instead, value accrues through an exchange rate that increases over time. As a result, redeeming sUSD0 returns more USD0 than initially deposited (assuming positive yield over the holding period).
Yield originates from the protocol’s underlying collateral stack, sovereign US Treasury Bills and other short-term yield-bearing assets, and is passed through to sUSD0 holders via the vault’s exchange-rate mechanism.
Key Facts
Underlying asset: USD0, the RWA-backed stablecoin at the core of Usual Protocol
Standard: ERC-4626 vault (non-rebasing, accrual via exchange rate)
Access: Permissionless; no KYC/KYB requirement
Yield source: Sovereign T-Bills and overnight reverse repos backing USD0 collateral
Yield distribution: Controlled via on-chain parameters; the rate may vary with market conditions and DAO decisions
Redemption math:
USD0 out = sUSD0 × exchangeRate(t ≥ 1)Contract address (Ethereum):
0xd861bE82dEe3223CFBEd160791f6550b0704D406
How sUSD0 Works
Deposit USD0 into the sUSD0 ERC-4626 vault.
Receive sUSD0 shares representing a proportional claim on the vault’s total assets.
Accrue yield passively as the sUSD0↔USD0 exchange rate increases over time.
Redeem anytime to unwrap sUSD0 and receive USD0 at the current exchange rate.
Because sUSD0 follows the ERC-4626 standard, it is straightforward to integrate across DeFi. Any protocol that supports ERC-4626 can generally support sUSD0 without custom adapter logic, simplifying accounting and composability.
Yield Source and Collateral Stack
The yield that accrues to sUSD0 traces back to the DAO revenue.
How yield reaches sUSD0 holders
The protocol captures yield generated by the underlying collateral and routes a portion of it to sUSD0 holders by increasing the vault’s exchange rate over time. Distribution parameters—including how much yield is allocated to sUSD0 and how quickly it accrues—are adjustable via USUAL governance.
sUSD0 vs. USD0 (At a Glance)
Purpose
Settlement asset
Savings instrument
Value behavior
Pegged 1:1 to USD
Grows via exchange rate
Access
Free mint / redemption
Wrap / unwrap via ERC-4626 vault
Use cases
Payments, collateral, trading
Yield generation, DeFi integration
Design
Rebase-free stablecoin
ERC-4626 wrapper (non-rebasing shares)
sUSD0 vs. the Bond Product (bUSD0)
Usual Protocol offers two distinct ways to earn yield on USD0, each aligned to different risk profiles and time horizons:
Mechanism
ERC-4626 vault; exchange-rate accrual
Liquid bond; daily USUAL token coupons
Lock-up
None — deposit and withdraw freely (3bips)
Bond with maturity date (June 2028)
Yield denomination
USD0 (real yield)
USUAL tokens (alpha yield) or Base Yield Guarantee
Yield type
Predictable, T-Bill-based
Variable; dependent on USUAL token price
Early exit
Instant redemption at current exchange rate
Secondary-market sale or recombination with rt-bUSD0
DeFi composability
High (ERC-4626 standard)
High (tradeable ERC-20; usable as collateral)
sUSD0 is designed for users seeking stable, predictable yield denominated in USD0, with no lock-up and no direct exposure to token price volatility. bUSD0 is designed for users willing to commit capital for potentially higher returns driven by USUAL emissions and bond discount dynamics.
Benefits
Predictable yield: Transparent accrual via a rising exchange rate, backed by sovereign instruments
Stable collateral base: Short-duration sovereign exposure (portfolio average duration < 0.33 years)
Non-rebasing design: DeFi-friendly for pools, lending markets, and integrations that prefer fixed balances
Permissionless access: Fully on-chain deposit and redemption—no intermediaries
Governance-aligned: Yield distribution parameters adjustable via USUAL governance
Real yield in USD0: Returns are denominated in USD0 and sourced from real-world fixed-income instruments (not primarily token emissions)
Rebasing Track
USD0 also supports a rebasing mode, where yield is distributed directly to USD0 balances at the “cash layer.”
This is part of Savings but lives on USD0 itself (not as a separate token). It is suitable for applications that prefer native balance growth over ERC-4626 wrappers, for example, wallets or payment interfaces where users expect their USD0 balance to increase automatically without wrapping into a vault token.
Contract Information
sUSD0
0xd861bE82dEe3223CFBEd160791f6550b0704D406
USD0 (underlying)
0x73A15FeD60Bf67631dC6cd7Bc5B6e8da8190aCF5
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