Liquity USD (LUSD)

Liquity USD (LUSD): An ETH-Backed Stablecoin Built Around Redemptions and Liquidations

Liquity USD is the stablecoin issued by Liquity V1, an Ethereum protocol that lets users borrow against Ether without recurring interest. Its design relies on overcollateralized Troves, a Stability Pool, direct redemptions, and a limited-governance operating model rather than discretionary monetary management.

What Liquity V1 does

Liquity V1 is a collateralized debt protocol for Ethereum. Users lock ETH in a smart contract position called a Trove and mint LUSD against it. The protocol describes LUSD as a USD-pegged stablecoin designed to remain overcollateralized, while allowing any LUSD holder to transfer or redeem the token without maintaining a Trove. The core borrowing model does not charge ongoing interest; instead, users pay issuance fees when creating debt and redemption fees when exchanging LUSD for collateral.

The practical use case is liquidity without selling ETH. A borrower can retain exposure to Ether while obtaining LUSD for trading, payments, liquidity provision, or other DeFi activity. That use case also creates direct risk: the debt is secured by ETH, so a fall in ETH value can push a Trove below its required collateral ratio and trigger liquidation.

Troves, collateral ratios, and liquidations

Each Trove must remain above Liquity V1’s minimum collateralization ratio of 110%. The protocol continuously uses an ETH-to-USD price feed to assess collateral value. If a Trove falls below the minimum, it becomes eligible for liquidation. The system also tracks a total collateralization ratio for all Troves and can enter Recovery Mode when that aggregate ratio falls below 150%; in that state, additional borrower actions are restricted or conditioned on improving system collateralization.

Liquidation proceeds are handled through two mechanisms. First, the Stability Pool uses deposited LUSD to cancel the debt of liquidated Troves, burning the corresponding LUSD and distributing the liquidated ETH to depositors. If the Stability Pool does not contain enough LUSD, the remaining collateral and debt can be redistributed across active Troves. This makes the Stability Pool a central risk-absorption component rather than a passive savings account: depositors can gain ETH, but their LUSD balance may be reduced when liquidations occur.

Redemptions are the main peg mechanism

Any LUSD holder can redeem the token directly against the system for approximately one dollar’s worth of ETH, less a redemption fee. Redemptions are applied to Troves in ascending order of collateralization, starting with the riskiest positions. In economic terms, this creates an arbitrage path when LUSD trades below its intended value: a holder can acquire discounted LUSD and redeem it for collateral at face value, subject to transaction costs and the applicable fee.

Redemptions also impose a cost on borrowers with comparatively weak collateralization. A Trove can be partially or fully redeemed against, reducing its debt and collateral. The mechanism is intended to support the peg without a central issuer promising to buy or sell LUSD in discretionary markets. It is not a guarantee that LUSD will trade at exactly one dollar, because execution costs, liquidity, oracle conditions, market demand, and protocol state can affect the result.

What LUSD is, and what LQTY does

LUSD is the debt token created when users borrow from Liquity V1; it is not the protocol’s incentive or fee-sharing token. LQTY has a separate role. The repository documentation describes LQTY staking as the route through which holders receive a share of system revenue from issuance and redemption fees. LQTY has also been distributed to Stability Pool participants through the Community Issuance contract. This separation matters because holding LUSD does not by itself provide governance rights or a claim on Liquity fees.

Liquity V1’s architecture was designed to minimize discretionary control. The project documentation describes stability as being maintained through collateral rules, redemptions, liquidations, incentives, and user behavior rather than active monetary governance. That reduces dependence on routine parameter votes, but it does not remove dependencies: the system still relies on smart-contract correctness, an ETH price feed, sufficient Stability Pool liquidity, Ethereum transaction execution, and external markets where LUSD can be acquired or used.

V1 remains distinct from Liquity V2

Liquity’s current official website presents Liquity V1 and LUSD separately from Liquity V2 and its BOLD stablecoin. The site states that V1 and LUSD remain available for users who prefer the original ETH-backed design, while V2 introduces different features such as user-set borrowing rates and support for selected liquid-staking tokens. LUSD should therefore not be treated as another name for BOLD, and claims about V2’s collateral types, rates, or incentives should not automatically be applied to LUSD.

The distinction is also relevant when reviewing deployments outside Ethereum mainnet. A token representation on another network may depend on a bridge, canonical messaging system, wrapper, or separate liquidity venue. Network labels and contract addresses should be checked independently before a user deposits, transfers, or redeems LUSD, because the risk profile of a representation can differ from the original Ethereum protocol.

Who the design may suit

LUSD is principally aimed at ETH holders seeking non-custodial borrowing and users seeking an Ethereum-native stablecoin with direct protocol redemption. Stability Pool participants are a second user group: they accept liquidation-related balance changes in exchange for exposure to liquidated collateral and, where applicable, LQTY incentives. DeFi applications may use LUSD as a dollar-denominated asset, but their own smart contracts and liquidity conditions create additional layers of risk beyond Liquity V1 itself.

Key takeaways

• LUSD is minted against ETH collateral in Liquity V1 Troves and is designed to remain overcollateralized.
• The Stability Pool absorbs eligible liquidations using deposited LUSD and distributes liquidated ETH to depositors.
• Direct redemption for ETH is the protocol’s central structural support for the LUSD peg.
• LUSD is the borrowing asset; LQTY is the separate fee-sharing and incentive token.
• Liquity V1 and LUSD are distinct from Liquity V2 and its BOLD stablecoin.
• Use of bridged or wrapped LUSD representations requires separate verification of contracts, bridges, and liquidity.

Risks and open questions

• ETH price-feed errors, delays, or abnormal market conditions could affect collateral valuation and liquidation outcomes.
• A depleted or thin Stability Pool may increase reliance on debt and collateral redistribution across active Troves.
• Smart-contract vulnerabilities could affect Troves, LUSD issuance, redemptions, liquidations, or LQTY-related contracts.
• Redemption mechanics support the intended peg but do not guarantee a constant market price after fees, gas costs, slippage, and liquidity constraints.
• LUSD activity on other networks may depend on bridge or wrapper infrastructure with risks not present in the Ethereum-native contracts.
• Borrowers remain exposed to forced liquidation and loss of collateral if ETH falls far enough or transactions cannot be executed in time.