What Is DeFi? Decentralized Finance Explained: Lending, Trading and Risks

Decentralized finance, usually shortened to DeFi, is an attempt to rebuild basic financial services, such as trading, lending and saving, as software that runs on public blockchains rather than inside banks and brokerages. Supporters see open, always-on markets. Critics see unaudited code, losses with no recourse and a magnet for scams. Understanding what DeFi actually is, and what it is not, helps you read the headlines without taking sides.

The core idea: code instead of intermediaries

In traditional finance, a company sits in the middle of each transaction. A bank matches borrowers and savers. A broker routes your trade to an exchange. A clearing firm settles it. You trust these firms, and they are regulated, insured in some cases, and legally accountable.

DeFi swaps the middle layer for smart contracts: programs stored on a blockchain that run automatically when conditions are met. Anyone with a compatible crypto wallet can interact with them. Most of the activity today runs on Ethereum and networks built to work alongside it, which we cover in our guide to Ethereum, smart contracts and gas fees.

Three features define the model:

• Open access. There is usually no application or approval; a wallet is enough.
• Transparency. The contract code and transactions are public, though that does not mean the code is safe.
• Self-custody. You hold your assets in your own wallet, rather than with a company, and you sign each transaction yourself.

What DeFi does: the main building blocks

Decentralized exchanges

A decentralized exchange, or DEX, lets people swap one token for another without an order book run by a company. Many use an automated market maker: a pool of two tokens held in a smart contract, with a formula that sets the price based on the pool's balance. When you swap, you trade against the pool.

The pools are funded by users called liquidity providers, who deposit tokens and earn a share of the trading fees. In return, they take on risks, including impermanent loss, where the value of their deposit can end up lower than if they had simply held the tokens.

Lending and borrowing

DeFi lending protocols let users deposit tokens to earn interest and let others borrow against collateral. Because there is no credit check, loans are typically over-collateralized: you must lock up more value than you borrow. If the collateral falls below a set threshold, the contract sells it automatically, a process called liquidation.

This protects lenders but can be harsh for borrowers in a fast-falling market, because liquidations can happen within minutes.

Stablecoins

Many DeFi products settle in stablecoins, tokens designed to track the US dollar. They give users a less volatile unit for trading, lending and payments. Their reliability depends on what backs them and how they are run, which we explain in our guide to how stablecoins work and what backs them.

Staking, yield and other products

Other DeFi activity includes staking tokens to help secure a network, depositing assets into "yield" strategies that move funds between protocols, and tokenized versions of other assets. Where a platform advertises returns, those returns come from somewhere: trading fees, borrower interest, newly issued tokens or leverage. Asking where the yield comes from is one of the most useful questions in DeFi.

DeFi versus traditional finance

The main risks

DeFi's openness is also its weakness. The main risks include:

• Smart contract bugs. A flaw in code can be exploited and funds drained. Audits reduce risk but do not remove it.
• Hacks and exploits. Attackers target contracts, connecting bridges between networks, and wallets.
• Price volatility. Token prices can swing sharply, which can trigger liquidations or erase gains.
• Impermanent loss. Liquidity providers can lose relative to holding.
• Scams. Fake tokens, fake websites and "rug pulls," where creators drain a project, are common. Our guide to crypto scams explains the warning signs.
• User error. Sending funds to the wrong address or approving a malicious contract usually cannot be undone.
• Regulatory risk. Rules are still developing, and a platform may be restricted or shut down.
• No safety net. DeFi deposits are not covered by FDIC or SIPC protection the way bank deposits and brokerage accounts may be.

US rules and taxes

DeFi sits in a legal gray area that US agencies have been working through. The SEC, the CFTC, the Treasury Department and state regulators each have a role, depending on whether a product looks like a security, a commodity derivative or a money service. Our overview of who regulates crypto in the US explains how that division works.

For taxes, the IRS treats digital assets as property. Swapping tokens, selling for dollars, or receiving rewards can each be taxable, and many DeFi activities generate several transactions. Because decentralized platforms typically do not send tax forms, users need to keep their own records of dates, amounts and values. The IRS publishes current guidance on digital assets at irs.gov, and a tax professional can help with complicated cases.

How to evaluate a DeFi product, in general terms

This is education, not a recommendation. If you are trying to understand a platform, these questions give you a structured way to think:

1. Who built it, and is the team identifiable?
2. Has the code been independently audited, and have the results been published?
3. How long has it operated, and has it been tested in volatile markets?
4. Where does the advertised yield actually come from?
5. What happens if something goes wrong, and is there any recourse?
6. How much could be lost, and can you afford that loss?

The bottom line

DeFi shows that financial services can be built as open software, and it has produced real innovation in how markets are designed. It also asks users to carry risks that banks and brokers normally carry for them. A reasonable position is neither hype nor dismissal: learn how the pieces work, treat advertised returns with skepticism, and remember that in a system without intermediaries, much of the responsibility rests with you.