What Is LUSD? Liquity's Decentralized Stablecoin Explained

LUSD is a decentralized stablecoin issued by the Liquity protocol, backed exclusively by ETH collateral, and distinguished by two unusual design choices: borrowing LUSD carries no ongoing interest charge, only a one-time issuance fee, and the protocol's core smart contracts are immutable, meaning they cannot be upgraded or altered by governance after deployment.

The zero-interest borrowing model

Most crypto-collateralized stablecoins, including DAI, charge an ongoing "stability fee," effectively interest, on borrowed stablecoins for as long as the loan remains open. Liquity took a different approach: borrowers pay a one-time fee when opening or adjusting a loan (called a "Trove" in Liquity's terminology), but no continuous interest accrues afterward. This can make LUSD meaningfully cheaper to borrow over long holding periods compared to protocols charging ongoing fees, particularly for users who intend to keep a loan open for an extended time.

The tradeoff is that Liquity's revenue model relies on this one-time fee plus liquidation-related mechanisms rather than continuous interest income, which shapes how the protocol's stability and incentive structures are designed compared to fee-based competitors like MakerDAO/Sky.

Single-collateral, ETH-only design

Unlike DAI, which has expanded to accept a wide basket of crypto and real-world asset collateral, Liquity deliberately restricts LUSD to ETH collateral only. This is a simplicity-focused design choice: fewer collateral types mean fewer oracle dependencies, fewer governance decisions about which assets to accept and at what risk parameters, and a more predictable, auditable risk surface overall. See our explainer on what DAI is for contrast on how a multi-collateral system manages that added complexity.

The cost of this simplicity is reduced flexibility: users who want to borrow against other crypto assets need to look elsewhere, and the protocol's growth is inherently tied to ETH's role as collateral rather than a broader diversified basket.

Immutable smart contracts

Perhaps Liquity's most distinctive design choice is that its core contracts are immutable, they were deployed without an upgrade mechanism and cannot be changed by any governance vote or admin key. This is a deliberate philosophical stance: rather than trusting ongoing governance to manage risk parameters wisely (as DAI's system does through active MKR/Sky governance votes), Liquity's designers built the risk parameters into the protocol from day one and removed the ability to change them.

The benefit is a strong guarantee against governance risk, no vote can alter collateral requirements, freeze the protocol, or change fee structures after the fact, which some users view as a meaningful trust advantage. The tradeoff is the same rigidity: if market conditions change in ways the original design didn't anticipate, the protocol cannot adapt, unlike DAI's system, which has evolved its collateral basket and risk parameters repeatedly over the years in response to changing conditions.

LUSD vs DAI: two philosophies

Feature	LUSD (Liquity)	DAI (MakerDAO/Sky)
Collateral types	ETH only	Diversified basket, including RWAs
Borrowing cost	One-time fee, no ongoing interest	Ongoing stability fee
Governance	None; immutable contracts	Active DAO governance
Adaptability	Fixed at deployment	Evolves via governance votes
Liquidation mechanism	Stability Pool + redistribution	Auction-based liquidation

The Stability Pool and liquidation mechanism

Liquity uses a distinctive liquidation approach: users can deposit LUSD into a "Stability Pool," which absorbs debt from liquidated Troves in exchange for a share of the seized ETH collateral, typically at a discount, making Stability Pool deposits a way to earn yield from the liquidation process itself. If the Stability Pool is insufficiently funded to absorb a liquidation, debt and collateral are redistributed proportionally across remaining open Troves instead. This differs from DAI's more traditional auction-based liquidation process, and it's designed to process liquidations quickly even during periods of high network congestion or gas costs.

Risks to understand

Single-collateral exposure to ETH means LUSD's system-wide health is entirely tied to ETH's price behavior, a sharp, sustained ETH crash stresses the entire protocol's collateralization at once, without the diversification benefit a multi-asset system like DAI's offers. Immutability, while eliminating governance risk, also means any unforeseen design flaw or changing market condition cannot be patched through a governance vote, the protocol simply has to weather it as originally built. As with any DeFi protocol, smart contract risk and oracle reliability remain relevant considerations regardless of these design choices.

Who LUSD tends to suit

Given its tradeoffs, LUSD tends to appeal most to users who specifically value predictability and minimized governance risk over flexibility, borrowers who plan to hold an open loan for a long period and want to avoid accumulating ongoing interest charges, and anyone specifically wary of DAO governance changing risk parameters after they've opened a position. It tends to suit ETH holders in particular, since the entire mechanism is built around that single collateral type; users wanting to borrow against a broader range of crypto assets are better served by a multi-collateral system like the one described in our guide on multi-collateral stablecoins.

Bottom line

LUSD offers a genuinely different philosophy from DAI: zero ongoing interest, ETH-only collateral, and fully immutable contracts that remove governance risk entirely but also remove the ability to adapt. It's a useful illustration that "decentralized stablecoin" isn't a single design template, different protocols make different, defensible tradeoffs between simplicity, adaptability, and trust-minimization, and understanding those tradeoffs matters more than treating all crypto-collateralized stablecoins as interchangeable.