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The problem with traditional liquidations

In traditional DeFi lending protocols, liquidations must be atomic — the collateral seizure and debt repayment happen in a single transaction. This atomicity requirement creates MEV extraction opportunities: liquidators compete in priority gas auctions, and the surplus flows to block proposers rather than to the lending protocol or its users.

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Why CoW Protocol is different

CoW Protocol’s settlement model separates operations into distinct phases:
  1. Collect trade amounts from users
  2. Execute interactions (AMM swaps, etc.)
  3. Transfer outputs to users
This sequential approach initially seems incompatible with atomic liquidations, since collateral disbursement and debt recovery happen in different calls. However, CoW Protocol’s immutable settlement contract provides strong on-chain guarantees that can replace the need for atomicity.

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The ERC-1271 smart order approach

The key insight is that lending protocols can use ERC-1271 signature validation to verify liquidation conditions at order execution time, while trusting the settlement contract to guarantee trade execution.

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How it works

  1. Create a liquidation order: The lending protocol (or a keeper) creates a CoW Protocol order where:
    • Sell token: The borrower’s collateral asset
    • Buy token: The debt asset needed for repayment
    • Limit price: Set generously to allow solver competition to improve the price
  2. ERC-1271 verification: During signature validation (when the settlement contract calls isValidSignature), the lending protocol’s smart contract verifies that:
    • The borrower’s position is eligible for liquidation
    • The collateral being sold covers the minimum debt owed
    • The order parameters are within acceptable bounds
  3. Settlement guarantees: The CoW Protocol settlement contract guarantees that the trader will receive at least the specified buy amount. This on-chain guarantee replaces the need for atomicity — the lending protocol can trust that if the order executes, the debt repayment will happen.
  4. Solver competition: Multiple solvers compete to fill the liquidation order, driving price improvement. This replaces the MEV extraction of traditional liquidations with genuine competition for the best execution price.

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Using pre/post hooks

CoW Hooks can handle additional bookkeeping:
  • Pre-hooks: Prepare the collateral for transfer (e.g., withdraw from a vault)
  • Post-hooks: Update the lending protocol’s accounting after the liquidation completes

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Advantages over traditional liquidations

AspectTraditionalCoW Protocol
MEV exposureHigh — priority gas auctionsProtected — batch auction with uniform clearing prices
Price discoverySingle liquidator sets priceMultiple solvers compete
Execution speedSingle blockSingle batch auction (can be fast with generous limit prices)
AtomicityRequiredReplaced by settlement contract guarantees
Flash loan dependencyOften neededNot required
This approach works best with smart contract wallets (e.g., Safe) or purpose-built liquidation contracts that implement ERC-1271. EOA-based positions require a wrapper contract.

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When to use this approach

CoW Protocol liquidations are most suitable when:
  • The lending protocol can tolerate a short delay (one batch auction cycle) for execution
  • MEV protection and price improvement are priorities
  • The protocol wants to eliminate dependency on flash loan infrastructure
  • Liquidation volumes are large enough to attract solver competition
For time-critical liquidations where sub-block execution is essential, traditional atomic approaches may still be preferable.
Last modified on March 12, 2026