That DeFi APY is not a savings rate

The app shows 8 percent. That number looks like a bank certificate of deposit. In DeFi lending markets, the displayed APY is a snapshot of what borrowers are paying, and what suppliers are earning, at that moment. It can move. Extra reward tokens are a separate program, not a locked add-on. Your principal is not insured.

This is general educational information from official Aave and Compound documentation. It is not a product tour, a return forecast, or a recommendation to supply or borrow. The 8 percent figure is a reader example, not a live rate.

What APY means in a lending app

Aave's glossary says APY includes compounding. APR does not. Compounding means earned interest is added to the balance and can itself earn interest. That still does not make the rate a promised savings yield.

Aave V3 documentation says interest rates follow utilization: the share of the pool that borrowers have already taken. When more of the pool is borrowed, rates typically rise. When less is borrowed, rates typically fall. Supplier yield is borrower interest after the protocol keeps a reserve factor, a cut of that interest that goes to the protocol treasury.

Aave's interest-rate strategy uses two slopes around an optimal utilization point. Below that point, rates move on a gentler slope. Above it, they can jump more sharply. Aave's borrowing help pages say displayed rates change with utilization and with governance parameter changes.

Why the number can change, and why it is not a CD

A bank CD quotes a rate the bank agrees to pay for a set term, with deposit insurance on eligible accounts at insured banks, subject to FDIC or NCUA limits. A DeFi APY does not work that way.

The 8 percent you see today can be lower tomorrow if borrowers repay and utilization drops. It can be higher if demand spikes. Some screens also fold in reward tokens. Compound's documentation treats protocol rewards as a separate program from the interest-rate model. Extra reward tokens are not a locked add-on to the interest rate.

Aave's risk documentation lists collateral risk, oracle risk, and smart-contract risk. None of that is deposit insurance. If a market fails, a smart contract is exploited, or an oracle is wrong, the displayed APY does not protect the principal.

Compound uses a related idea, with different rules

Compound III documentation defines utilization as total borrows divided by total supply. Rates accrue every second. After a set usage point, they rise faster. Governance sets those parameters. Collateral in Compound III does not earn or pay interest. That is one example of how two well-known protocols can show a rate and still mean different things. Read the market you are in, not a generic DeFi APY label.

What to check before you treat the number as income

Ask whether the figure is APY or APR. Ask whether it includes reward tokens. Ask how utilization is calculated on that market. Ask what happens to your principal if the rate goes to zero. Then read the protocol's own docs for that version. Do not treat any screenshot as a locked return.

Sources

Aave glossary: https://aave.com/docs/resources/glossary
Aave V3 overview: https://aave.com/docs/aave-v3/overview
Aave V3 interest-rate strategy: https://aave.com/docs/aave-v3/smart-contracts/interest-rate-strategy
Aave, borrow tokens: https://aave.com/help/borrowing/borrow-tokens
Aave risks: https://aave.com/docs/resources/risks
Compound III interest rates: https://docs.compound.finance/interest-rates/
Compound protocol rewards: https://docs.compound.finance/protocol-rewards/

Disclosure: This article is general educational coverage of dated Aave and Compound documentation. It does not quote a live rate, does not forecast returns, and is not a product recommendation. The accompanying illustration is generated editorial art, not a bank document or app screenshot. This article is not financial, legal, or investment advice. AI-assisted research and writing. Cited sources, not AI alone, support the claims.