How DeFi Lending Protocols Work: Pools, Utilization and Liquidations

DeFi lending protocols let anyone lend or borrow crypto through smart contracts. Behind the simple deposit button is a system of pools, interest rate models, price oracles and automated liquidations.

The basic model

  1. Lenders deposit an asset into a pool and receive a token or record representing their share.
  2. Borrowers lock collateral worth more than they borrow.
  3. Borrowers pay interest, which is shared among lenders after any protocol fee.
  4. If a borrower’s collateral falls too far, anyone can liquidate the position for a reward.

Utilization and interest rates

Utilization is the share of a pool that is borrowed. Most protocols raise rates gradually as utilization rises and then steeply above a target level, to attract more deposits and discourage borrowing. That is why rates can jump within hours when demand spikes.

Oracles

Protocols need prices to know when a loan is under-collateralized. They get them from oracles, which aggregate market prices. A wrong or manipulated price can cause unfair liquidations or leave the protocol with bad debt.

Pooled vs isolated markets

PooledIsolated
StructureMany assets share one pool of riskEach market has its own collateral and loan asset
AdvantageDeep liquidityA problem in one market does not spread
Trade-offOne bad asset can affect everyoneLiquidity is spread thinner

Governance and admin controls

Parameters such as collateral factors and rate curves are often changed by governance votes or admin keys. Check who can change them and how quickly, because those changes affect your risk.

Ready to try? Read how to lend crypto step by step, or back to the crypto lending hub.

Frequently asked questions

Mostly traders and investors borrowing against their crypto, often for leverage or liquidity.

When utilization is very high, lenders may have to wait to withdraw until loans are repaid or new deposits arrive.

Debt that is no longer covered by collateral because liquidation came too late. Lenders may share the loss.

This page is for educational purposes only and is not financial, investment or tax advice. Crypto assets are volatile; you can lose all of your money.