How Aave and Compound Price Liquidity Through Utilisation

Decentralised finance lending markets allow users to supply crypto assets, earn interest, and borrow without a conventional bank approving the transaction. Aave and Compound are two of the best-known protocols in this sector, and both use utilisation to connect market demand with the cost of borrowing.

The central idea is straightforward: when a large share of deposited liquidity has been borrowed, the protocol raises rates to attract more supply and discourage additional borrowing. When liquidity is plentiful, rates generally fall. The details differ between Aave and Compound, and those differences matter for anyone assessing yield, liquidation risk, or the sustainability of a DeFi strategy.

Utilisation is the engine behind lending rates

Utilisation measures how much of a lending pool is currently borrowed. A simplified formula is:

Utilisation = borrowed assets ÷ total supplied assets

If a pool contains 1,000 ether and borrowers have taken 700 ether, utilisation is 70%. Suppliers receive interest from borrowers, while borrowers pay a rate determined by the protocol’s interest rate model. The spread helps cover reserves, incentives, and the risks associated with the market.

At low utilisation, borrowing is relatively cheap because the pool has spare capacity. As utilisation rises, the borrowing rate increases. This protects against a situation in which every supplier attempts to withdraw funds while too little liquidity remains available. The model therefore acts as an automated pricing mechanism rather than a fixed bank rate.

How Aave uses a kinked interest curve

Aave commonly uses a two-slope model with a “kink”, also called the optimal utilisation point. Below that threshold, the variable borrow rate rises gradually. Once utilisation moves beyond the kink, the rate increases sharply to encourage repayment and new deposits.

The parameters vary by asset and network. A stablecoin pool may have a different optimal utilisation target from a volatile asset such as wrapped bitcoin or ether. Aave governance can adjust the base rate, slopes, reserve factor, and utilisation target through votes or risk-management processes. These settings reflect liquidity depth, collateral quality, market volatility, and the possibility of an abrupt withdrawal wave.

Aave suppliers usually earn a variable rate that is linked to borrower payments, less the protocol’s reserve allocation. Borrowers can face rapid changes in their cost of capital when utilisation moves quickly. In stressed markets, a deposit that appeared to offer attractive income yesterday may produce a lower net return after incentives change, while a leveraged position can become expensive to maintain.

How Compound’s model responds to demand

Compound also uses utilisation-based rate models, with the exact structure depending on the version and market. Traditional Compound markets use a kinked curve: rates rise at a slower pace before the target utilisation level and much faster after it. Compound III, often called Comet, takes a different approach by focusing each market on a base asset, such as a stablecoin, with approved collateral assets supporting borrowing.

This design can make the relationship between liquidity and rates easier to analyse within a particular market. Governance still determines important parameters, including the base rate, slopes, reserve settings, collateral factors, and borrowable assets. The protocol’s token incentives may influence a user’s effective yield, but those rewards are separate from the underlying interest paid by borrowers.

For Australian users, the distinction is relevant when comparing a DeFi return with an AUD savings account or a term deposit. A quoted annual percentage yield in US dollars does not remove exchange-rate risk, and a strong Australian dollar can reduce the value of overseas-denominated returns. Borrowing costs can also change before funds are converted back into AUD.

Why the kink matters during market stress

The kink is designed to prevent a pool from becoming fully utilised. Below the target, the protocol tolerates relatively efficient capital use. Above it, the steep rate increase makes borrowing less appealing and encourages suppliers to add liquidity. This is especially important for stablecoin markets, where utilisation can jump when traders seek leverage or move quickly into cash-like assets.

A user may still encounter practical limits. Available liquidity can be lower than total deposits because some assets are locked in outstanding loans. Withdrawals may become difficult when utilisation approaches 100%, even though the smart contract remains operational. Liquidations can add further pressure if falling collateral prices trigger sales while borrowers are already paying elevated variable rates.

Protocol risk also extends beyond the formula. Smart-contract vulnerabilities, oracle failures, governance decisions, bridge incidents, and depegging events can affect returns. Research into route optimisation technology illustrates a wider lesson for emerging markets: automated systems still depend on accurate data, defined controls, and reliable operational assumptions.

Reading rates before supplying or borrowing

A sensible review begins with the asset, chain, and market configuration rather than the headline yield. Check current utilisation, the optimal utilisation threshold, the borrow rate, the supplier rate, reserve allocation, and any temporary token incentives. A high supplier APY may signal heavy borrowing demand, but it can also indicate a market approaching a liquidity squeeze.

Australian participants should also account for local compliance and record-keeping realities. DeFi activity may create tax consequences, and swapping tokens, receiving rewards, or closing a leveraged position can require detailed transaction records. ASIC and AUSTRAC considerations may apply depending on the service, business structure, and activities involved, while rules and regulatory guidance can change.

Network fees and timing matter as well. A small position on Ethereum may be uneconomic during a busy Sydney trading session, whereas a lower-cost network can introduce separate bridge or liquidity risks. Treat protocol dashboards as live market data, not guaranteed offers: rates can change block by block as borrowers enter, repay, supply, or withdraw.

For practical analysis, compare the current utilisation with the kink, then stress-test the position against a sudden rate increase, a fall in collateral value, and reduced exit liquidity. The key takeaway is simple: before using Aave or Compound, understand what is driving utilisation today and how the rate model is designed to react tomorrow.