Liquidation
Liquidation in Lista Lending is a vital risk management tool that safeguards lenders’ capital by ensuring borrowers maintain sufficient collateralization. Mirroring Morpho’s design, Lista Lending implements two liquidation approaches on BNB Chain:
Standard Liquidation: A core protocol feature enabling full or partial liquidation of a borrower’s position when their Loan-To-Value (LTV) exceeds the market’s Liquidation Loan-To-Value (LLTV) threshold.
Pre-Liquidation: An optional, opt-in mechanism via an external contract, allowing smaller, incremental liquidations before reaching the standard threshold, providing borrowers with a safety buffer.
Integrated into Lista Lending’s upgradeable vault system, these mechanisms ensure market stability while supporting its vault-centric, permissionless lending model.
Understanding Loan-To-Value (LTV)
The Loan-To-Value (LTV) ratio is a critical metric assessing a position’s risk by comparing debt to collateral value.
How to Calculate LTV
The LTV is calculated as: LTV = (Borrowed Amount × Oracle Price) / (Collateral Amount × Oracle Price Scale)
Where:
Borrowed Amount: The total borrowed assets (e.g., lisUSD).
Oracle Price: The price from the market’s oracle (e.g., Chainlink).
Collateral Amount: The supplied collateral (e.g., pt-clisBNB).
Oracle Price Scale: 1e36 (standard scaling factor).
Standard Liquidation
Standard liquidation is Lista Lending’s primary defense against borrower defaults, embedded in the protocol’s core contracts.
When Is a Position Liquidatable?
A position becomes liquidatable when LTV > LLTV
This occurs due to:
A drop in collateral value (e.g., pt-clisBNB price falls).
An increase in debt from accrued interest.
A combination of both.
Example:
Collateral: $100 (pt-clisBNB).
LLTV: 80%.
Safe: Borrowed value ≤ $80 (LTV ≤ 80%).
Liquidatable: Borrowed value > $80 (LTV > 80%).
How Standard Liquidation Works
When triggered, any external party (liquidator) can repay part or all of the borrower’s debt, receiving collateral plus a bonus determined by the Liquidation Incentive Factor (LIF).
Liquidation Incentive Factor (LIF)
The LIF sets the bonus: LIF = min(M, (1/β × LLTV + (1 - β)))
Where:
β: 0.3 (constant).
M: 1.15 (cap).
For LLTV = 80%, LIF ≈ 1.06 (6% bonus); initial default set at 1.048 (4.8%) per Lista DAO.
All LIF value goes to the liquidator; Lista Lending takes no fee.
Standard Liquidation Step-by-Step
Initial Position:
Borrower deposits $100 pt-clisBNB, borrows $70 lisUSD (LLTV = 80%).
Interest accrues, raising debt to $80.0001.
LTV = 80.0001% > 80% → Liquidatable.
Liquidation Process:
Liquidator repays $80.0001 lisUSD.
LIF = 1.048 (4.8% bonus, per section 2.6.3).
Seized collateral: $80.0001 × 1.048 = $83.84 pt-clisBNB.
After Liquidation:
Borrower: Debt cleared, retains $16.16 pt-clisBNB.
Liquidator: Spent $80.0001, received $83.84; profit = $3.84 minus gas fees.
Key Features
Liquidation Amount: Up to 100% of debt in one transaction.
Trigger: LTV > LLTV.
Incentive: Fixed LIF based on LLTV (e.g., 4.8%).
Borrower Impact: Potential full liquidation.
Implementation: Core contract feature.
Pre-Liquidation
Pre-liquidation is an optional, opt-in mechanism offering a buffer before standard liquidation.
What Is Pre-Liquidation?
Pre-liquidation enables partial position closure when LTV exceeds a predefined Pre-Liquidation Loan-To-Value (preLLTV) but remains below LLTV, reducing risk incrementally.
Example:
Collateral: $100 pt-clisBNB.
LLTV: 80%, preLLTV: 75%.
Safe: LTV ≤ 75%.
Pre-Liquidatable: 75% < LTV < 80%.
Fully Liquidatable: LTV > 80%.
Pre-Liquidation Parameters
preLLTV: Threshold for pre-liquidation (e.g., 75%).
Pre-Liquidation Close Factors (preLCF₁ & preLCF₂): Max debt repayable, scaling linearly: preLCF = [(LLTV - LTV)/(LLTV - preLLTV)] × preLCF₁ + [(LTV - preLLTV)/(LLTV - preLLTV)] × preLCF₂
Pre-Liquidation Incentive Factors (preLIF₁ & preLIF₂): Bonus scaling between preLIF₁ and preLIF₂ based on LTV.
Pre-Liquidation Oracle: Assesses pre-liquidation eligibility (may match market oracle).
Pre-Liquidation Step-by-Step
Initial Position:
Borrower deposits $100 pt-clisBNB, borrows $75 lisUSD (LLTV = 85%, preLLTV = 79%).
Collateral drops, LTV rises to 80%.
79% < LTV (80%) < 85% → Pre-Liquidatable.
Pre-Liquidation Process:
Pre-liquidator repays 50% of $80 debt ($40), assuming preLCF = 50%.
preLIF = 1.03 (e.g., lower than standard 1.05 for 85% LLTV).
Seized collateral: $40 × 1.03 = $41.2.
After Pre-Liquidation:
Borrower: $40 debt remains, $58.8 pt-clisBNB left; new LTV = 68%.
Pre-liquidator: Profit = $1.2 minus fees.
Key Features
Trigger Zone: preLLTV ≤ LTV < LLTV.
Closure: Limited by preLCF (e.g., <50%).
Incentive: Dynamic preLIF, typically lower than LIF.
Borrower Impact: Incremental deleveraging.
Implementation: Opt-in via external PreLiquidation contract.
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