🔴 Liquidations — Health Factor, Thresholds & Bot Mechanics
When your collateral stops covering your debt, liquidators step in. Aave's health factor is the gate. This page shows how it's calculated, how bots compete for your collateral, and how to keep yourself safe.
⚖️ Health Factor Calculator
Health Factor = (Collaterals × Liquidation Threshold) ÷ Borrowed Value. HF > 1.0 means safe; HF < 1.0 means liquidatable.
🔄 Liquidation Flow — Step by Step
When a position's health factor drops below 1.0, anyone can call liquidate().
Here's exactly what happens, in order, on-chain:
liquidate(address reserve, address user, address collateral, uint256 amount, bool receiveAToken). The protocol validates the health factor is below 1.0. Close factor (≤50%) determines how much debt gets covered.amount × (1 + liquidationBonus) of the collateral asset to the liquidator. The bonus (typically 5–15%) compensates for gas, slippage, and execution risk. ETH liquidation bonus: 8.5% on mainnet.📊 Health Bar — Position Over Time
Watch your health factor deplete in real-time as collateral price drops. The red zone (HF < 1.0) is the liquidation trigger.
📋 Per-Asset Liquidation Thresholds (Aave V3 Mainnet)
| Asset | LT (Liquidation Threshold) | Liq. Bonus | Max LTV | Reserve Factor |
|---|---|---|---|---|
| WBTC | 70% | 15% | 65% | 20% |
| ETH | 82.5% | 8.5% | 80% | 15% |
| wstETH | 89% | 6% | 85% | 15% |
| USDC | 90% | 5% | 85% | 10% |
| DAI | 90% | 5% | 85% | 10% |
| LINK | 75% | 10% | 70% | 20% |
Note: Lower liquidation thresholds (e.g., WBTC 70%) means more price movement before liquidation. Higher thresholds (e.g., USDC 90%) are safer but offer less borrowing power per dollar of collateral.
📉 Case Study: March 12–13, 2020 — "Black Thursday"
On March 12, 2020, ETH dropped roughly 40% in a single hour during the COVID-19 market crash. Hundreds of MakerDAO CDPs and Aave V1 positions became underwater simultaneously.
At the same time, Ethereum network gas prices spiked to 200+ gwei due to market panic transactions. Many keepers and arbitrage bots couldn't afford to execute liquidations — their transactions were stuck. The result: some positions were liquidated at $0 bids — liquidators claiming collateral for almost nothing because no one else could compete.
Lesson learned: Aave V3 introduced per-collateral liquidation caps and improved gas efficiency to prevent cascading liquidations. Users learned to maintain health factors well above 1.0 as a buffer.
🛡️ How to Protect Yourself
Keep a 2x buffer. If ETH drops 50%, you'd still be above HF 1.0 with ETH as collateral at 82.5% threshold.
Borrow USDC against USDC or wstETH. No volatile collateral = no liquidation risk from price swings.
Use DeFi internals or Tenderly alerts to get notified when your HF drops below 1.5. Add collateral before it's too late.
Anatomy of a Liquidation
Aave's liquidation mechanism is triggered when healthFactor < 1.0.
At that point, the position is considered insolvent from the protocol's perspective, even if the collateral is technically still worth more than the debt in absolute terms.
The gap between the collateral value and the debt value is covered by the liquidation bonus paid to the keeper.
The close factor determines what fraction of the debt a liquidator can seize in one call — set at 50% in Aave V3. This means even a fully underwater position takes at least two liquidation calls to fully close. Per-collateral caps (introduced in V3) prevent a single asset from being liquidated all at once, protecting against market manipulation.
Bot Economics
Liquidators run infrastructure that costs money: RPC calls, EigenLayer AVS monitoring, gas, and dev ops. The economics only work when the liquidation bonus exceeds the operational costs plus gas. During periods of network congestion, fewer bots compete, which can lead to larger profits for the liquidators who do execute — and larger losses for the liquidated users.
- What's the difference between liquidation threshold and liquidation penalty?
- The liquidation threshold (e.g., 82.5% for ETH) is the collateral value at which a position becomes unsafe — it's used in health factor math. The liquidation penalty (e.g., 5–10%) is the bonus a liquidator receives on top of the seized debt's value. Both exist on Aave, but they serve different roles in the safety mechanics.
- Can you be partially liquidated?
- Yes. Aave v3 liquidators can close up to 50% of a position's debt in a single liquidation call. If you have a large position, you can be liquidated multiple times across different transactions until your health factor recovers above 1.0.
- Are flash loan liquidations considered risky or unfair?
- Flash loan liquidations are completely legitimate on-chain mechanics. A liquidator borrows capital just long enough to execute a liquidation and repay the flash loan in the same block. This actually improves market efficiency and protects protocol solvency. The practice has been standard since 2020.
- What happens to the collateral a liquidator receives?
- The liquidator receives the seized collateral (e.g., ETH) plus the liquidation bonus. They typically immediately sell it on a DEX to realize their profit in DAI or USDC, repaying the flash loan and pocketing the spread. This selling pressure also helps prices on other markets converge.
- How do Aave v3 per-collateral caps prevent cascading liquidations?
- In v3, governance can set a maximum amount of a single collateral type that can be liquidated within a single block or time window. This prevents a massive price drop from triggering all unhealthy positions at once, which could overwhelm the auction mechanism and leave the protocol with uncollateralized debt.