If you have used a decentralized exchange or a lending app on Base, you may have noticed something that would be unusual at a bank: nobody asked for your name, your income, or your credit score. Instead, the protocol asked you to deposit collateral worth more than the amount you want to borrow. This article explains how that model works, why it exists, and what happens if your collateral loses value.
The basic idea
Traditional lenders check whether you are likely to repay a loan. They look at your income, your credit history, and often ask for collateral like a house or a car, but even then they extend some trust based on who you are.
Decentralized lending protocols cannot do any of that. A smart contract does not know your name or your income, and it has no legal system to chase you down if you disappear. So instead of trusting the borrower, these protocols remove the need for trust entirely. You deposit an asset as collateral, and the protocol lets you borrow against it, but only up to a fraction of what you deposited. If your collateral drops too far in value, the protocol can sell it automatically to cover the loan. No court, no collections agency, just code enforcing the rule.
This is called overcollateralized lending, and it is the model used by most lending protocols active on Base, including Aave and Moonwell.
Collateral factors, in practice
Each asset a protocol accepts as collateral is assigned a collateral factor, sometimes called a loan-to-value ratio. This number caps how much you can borrow against a given deposit.
For example, if a stablecoin like USDC has a collateral factor of 75%, depositing $1,000 worth of USDC lets you borrow up to $750 worth of another supported asset. More volatile assets, like smaller-cap tokens, typically get lower collateral factors, because their price can move sharply and the protocol needs a bigger buffer before the loan becomes unsafe.
The gap between what you deposited and what you borrowed is what protects the lender on the other side of the loan. As long as your collateral stays comfortably above the value of your debt, the position is considered healthy.
What liquidation means
The risk shows up when the collateral's value falls relative to the debt. Every lending protocol tracks a health factor, or something equivalent, for each borrowing position. It compares the current value of your collateral against the value of what you owe, adjusted for the collateral factor.
If the price of your collateral drops enough that this ratio crosses a set threshold, the position becomes eligible for liquidation. At that point, anyone, usually an automated bot watching the chain for exactly this opportunity, can repay part or all of your debt and claim a portion of your collateral in return, typically at a discount as their incentive for doing the work. This happens on-chain, in a single transaction, without waiting for you to respond.
Liquidation is not a penalty in the sense of a late fee. It is the mechanism that keeps the protocol solvent. Without it, a lender could end up holding debt that is worth more than the collateral backing it, and the whole system would need some other way to cover the shortfall.
Why borrowers use this at all
Borrowing against collateral instead of selling it outright serves a few purposes. Someone holding ETH who wants USDC for a purchase or another opportunity can borrow against the ETH instead of selling it, avoiding a taxable event in many jurisdictions and keeping exposure to ETH's price. Others use it to increase exposure to an asset they already hold, by borrowing against it and using the proceeds to acquire more, though this also multiplies the risk of liquidation if the price moves against them.
Neither of these is free. Borrowing costs interest, usually a variable rate set algorithmically based on how much of the pool is currently being borrowed. When more people want to borrow, rates rise to attract more lenders and slow down borrowing; when demand drops, rates fall.
What to actually watch if you borrow
If you open a borrowing position on any protocol, a few things are worth checking before and after:
- Your health factor or equivalent metric. Most protocol interfaces show this directly. Understand what number counts as safe and what triggers liquidation.
- How volatile your collateral is. A stablecoin-backed position is far less likely to move suddenly than one backed by a token that can swing 20% in a day.
- Whether the protocol's interest rates and collateral factors are shown clearly before you commit, and whether the protocol has a track record and has been audited. Depositing funds into an unaudited or unfamiliar protocol carries risk independent of the lending mechanics themselves.
- That you are interacting with the real protocol contract, not a phishing clone. Confirm the URL and, if you are comfortable checking it, the contract address on Basescan before approving any large deposit.
The takeaway
Overcollateralized lending replaces trust in a borrower's identity with trust in math and price feeds. It lets anyone with crypto assets borrow against them instantly, but it shifts all the risk management onto the borrower: stay well above the liquidation threshold, understand how quickly your specific collateral can lose value, and remember that nobody is going to call you with a warning before a liquidation bot does its job.
Sources: Moonwell Protocol & WELL Token Guide: DeFi Lending on Base & Moonbeam, Forces Reshaping Decentralized Lending In 2026