Stable Vault Features

Stable Vaults convert variable DeFi lending rates into a predictable stable-rate product. When a user deposits, their position accrues at a locked per-second rate defined by their assigned SubVault, regardless of how underlying market rates fluctuate. The off-chain rebalancer continuously optimizes yield strategy allocations to sustain committed rates across the user base, absorbing market volatility within the Stable Vault smart contract system rather than passing it through to depositors.

Deposits are not tied to a single yield source. The Allocator routes assets across multiple approved ERC-4626 yield strategies, such as Aave v4 markets, Aave v3 markets, the Savings GHO vault, or any other compliant vault approved by the integrator. The off-chain manager rebalances allocations between strategies as market conditions change, diversifying yield sources and sustaining committed rates without any action required from depositors.

The system spans multiple networks. The Accounting Chain is the source of truth for user balances and withdrawals, while one or more Earning Chains host additional yield strategies. This lets the vault allocate deposits to yield opportunities wherever they exist, and lets users bridge their IOUs to redeem into assets available on other supported chains. Funds move between chains through multiple approved bridge providers. See Architecture for how the chains fit together.

Each user's position belongs to exactly one SubVault. A SubVault defines a set per-second accrual rate, and a user's withdrawable balance is their shares multiplied by the SubVault's current conversion rate. Because different SubVaults carry different rates, operators can assign different APYs to different user segments based on loyalty tiers, promotional campaigns, subscription levels, or other product logic. SubVault assignment is managed off chain: it is applied at the point of deposit and can be updated at any time afterward, throughout the life of the user's position.

Deposit access to the Stable Vault can be restricted to a set of approved wallets. This allows operators to run controlled embedded earning programs where only eligible users, such as those who have completed KYC, belong to a specific tier, or have been explicitly enrolled, can deposit. The allowlist is managed per deployment and does not affect the ability of existing depositors to withdraw.

The system tracks each user's original deposit principal separately from accrued interest. Principal is always redeemable as IOUs, with no additional conditions. Interest redemption is gated by the system's trusted, price-weighted surplus, meaning users can only convert accrued interest into IOUs when the system's assets exceed its obligations by that amount. Privileged callers can claim surplus interest as protocol revenue via claimSurplusInterest, subject to the same surplus check.

Withdrawal fees are configured per asset in basis points and applied by the Withdrawal Execution Policy at redemption time. Because fees are set per asset, the vault can support multiple stablecoins as eligible deposit and withdrawal assets while preventing users from taking advantage of the system for one-to-one swaps between them.

All supported stablecoins are treated as interchangeable inside the vault. When a user deposits, the system validates the asset's price and credits the position in the vault's denomination currency, valued at nominally one U.S. dollar, so what a user deposited places no restriction on what they can withdraw. At withdrawal, users choose any supported output asset on the chain where they redeem, and the vault manager is responsible for ensuring the system holds enough assets on each chain, in each supported denomination, to fulfill instant withdrawals. A user who deposited USDC may redeem into USDT, GHO, or another supported asset on the Accounting Chain, or bridge their IOUs to an Earning Chain to redeem into assets available there such as PYUSD or RLUSD.

Asset support is controlled by the Asset Registry, which tracks whether an asset may be deposited by users, deposited into the Allocator, used as a swap input, or received as a swap output. Assets can be marked as distrusted to exclude them from the system's surplus accounting without blocking users from voluntarily redeeming IOUs into those assets, ensuring the system accounts conservatively for assets that have depegged or whose price integrity is uncertain.

A global redemption rate limit throttles the total volume of IOU redemptions across all users and assets within a given period, bounding how quickly value can exit the system during abnormal conditions. The limit carries configurable floor values that prevent the policy from being tightened below a minimum throughput, so redemptions can never be effectively frozen through configuration alone.