Topic: Crypto · Type: Evergreen · Reading time: ~8 min

Your bank earned a net interest margin of roughly 3% last year. You probably earned 0.5% on your savings account. DeFi is, at its core, a direct challenge to that arrangement — cut out the intermediary, run the whole system on open code, and let the spread go somewhere other than a bank's shareholders. Whether that promise holds up is a different question.

The term "decentralised finance" gets used to mean everything from trading obscure tokens to a genuine reimagining of global financial infrastructure. This piece is about the actual mechanics — what decentralised finance is, how the main protocols work, what the numbers say about risk, and how to think about it as part of a broader financial life.

The core idea: replacing institutions with code

Traditional finance runs on trust in institutions. When you deposit money with a bank, you trust that it will lend responsibly, hold adequate reserves, and honour your withdrawal. The system works, mostly, but it comes with costs: fees, delays, access restrictions, and opacity about how your money is actually being used.

DeFi replaces institutional trust with mathematical trust. Smart contracts — self-executing code stored on a blockchain — handle lending, trading, and borrowing automatically, according to rules anyone can read and verify. There is no loan officer deciding whether to approve your application. There is no settlement delay waiting for a back-office team. The contract executes, or it doesn't.

As of mid-2025, more than 9.7 million unique wallets were actively interacting with DeFi protocols, and weekly trading volume on decentralised exchanges averaged around $18.6 billion. These aren't just crypto speculators chasing yields — Visa now settles transactions in USDC, JPMorgan launched an on-chain money market fund, and European banks including Société Générale have extended offerings into regulated DeFi protocols. The institutional migration is real, even if retail adoption remains early-stage.

Worth knowing: DeFi lending platforms currently have roughly $55 billion in total value locked (TVL) — the industry's measure of how much capital is actively working inside protocols. That figure sat at $54 billion at the start of 2024 and crossed $100 billion by year-end, before settling back as market conditions shifted.

The five things you can actually do with DeFi

Most explanations of DeFi describe it abstractly. Here are the concrete things people actually use it for:

1. Lending and borrowing. Platforms like Aave and Compound let you deposit crypto assets and earn interest, or borrow against collateral you already hold. Interest rates adjust automatically based on supply and demand — no credit check, no application. The catch: loans are over-collateralised. To borrow $1,000 worth of ETH, you might need to deposit $1,500 worth of another asset. That limits its usefulness if you need cash, but makes it useful for investors who want liquidity without selling their holdings and triggering a taxable event.

2. Trading on decentralised exchanges (DEXs). Platforms like Uniswap allow peer-to-peer token swaps without a centralised intermediary holding your funds. You trade directly from your own wallet. DEX spot volume reached 29.65% of total crypto trading by mid-2025 — up 150% from the previous quarter — which tells you this is no longer a niche activity.

3. Yield farming and liquidity provision. You deposit pairs of tokens into a liquidity pool, which other traders use for swaps. In return, you earn a share of the trading fees. Returns are quoted as APY and can look attractive, but they fluctuate dramatically and come with a specific risk called impermanent loss — where the value of your deposited tokens can end up lower than if you'd simply held them, depending on price movements.

4. Stablecoins. Much of DeFi runs on stablecoins — crypto assets pegged to fiat currencies, typically the US dollar. They let you participate in DeFi yields without full exposure to crypto price swings. If you've read our overview of how stablecoins work and whether they're actually safe, the short version is: the answer depends heavily on the type of stablecoin and who issues it.

5. Real-world asset tokenisation. This is where DeFi starts to look genuinely interesting for mainstream investors. Protocols are now tokenising treasury bills, real estate, and private credit — bringing the yields of traditional finance onto the blockchain. By mid-2025, tokenised real-world assets were one of the fastest-growing segments in the entire DeFi market, projected to expand at a 39.72% CAGR through 2031.

The risk picture, honestly

Here's where most DeFi explainers get soft. The risks are not hypothetical.

In the first half of 2025 alone, investors lost $2.5 billion to hacks and scams. In 2024, over $1.12 billion disappeared across 79 separate exploits. The most common cause of loss in 2024 was not clever smart contract hacks — it was compromised private keys, accounting for 80.5% of stolen funds. Which means most losses came from the human layer, not the code.

This is the part that competitor articles skim past: DeFi transfers all operational risk to the user. In traditional banking, if someone fraudulently accesses your account, you have recourse. Fraud protection, deposit insurance (up to €100,000 under EU rules, £85,000 in the UK, $250,000 via the FDIC in the US). In DeFi, if you click a malicious link, approve the wrong smart contract, or lose your seed phrase, the transaction is final and irreversible. No appeal. No support desk.

Smart contract risk is also real, even for audited protocols. A "2021 audit for a 2025 V3 contract" — as one DeFi security guide puts it — is not an audit for the code you're actually using. Protocols are updated, and audits don't always follow. And then there's protocol risk: governance attacks, oracle manipulation (where the price feeds that contracts rely on are corrupted), and rug pulls — where the team behind a project withdraws liquidity and disappears.

None of this means DeFi is a scam. It means it's a genuinely new risk category that deserves the same sober analysis you'd apply to any other financial instrument. If you're thinking about how much of your overall portfolio should be in crypto at all, our analysis of the right allocation to crypto for most investors is a useful starting point before touching DeFi specifically.

What MiCA changes for European users

If you're based in the EU, the regulatory picture shifted materially in 2025. The Markets in Crypto-Assets regulation (MiCA) is now in full effect, and it's already reshaping how DeFi protocols operate in Europe.

The short version: MiCA-compliant DeFi products captured 35% of total EU DeFi transactions in 2025, up from just 14% in 2024. Institutional investors who previously sat on the sidelines are entering — institutional DeFi participation rose approximately 40% as MiCA provided the legal clarity they needed. Over 30% of institutional investors in the EU increased their crypto holdings after MiCA's investor protection measures took effect.

The trade-off is complexity. Protocols that want to operate in the EU now face mandatory disclosure requirements, governance standards, and for some, KYC obligations — which cuts against DeFi's founding ethos of permissionless access. Uniswap has already geo-restricted certain tokens for EU users. Roughly one-third of DeFi projects with European operations have either relocated to jurisdictions like Switzerland or Singapore, or paused EU activity entirely.

For everyday users, MiCA's most practical effect is that the distinction between compliant and non-compliant protocols matters now. Using an unregistered platform could mean losing consumer protections you'd otherwise have, and the regulator is watching — over €540 million in fines have been issued since MiCA implementation began.

The broader picture here connects to the question of how crypto regulation in 2025 changes the game for investors — the answer is that it creates more legibility, at the cost of some flexibility.

What this actually means for you

DeFi is not a replacement for your savings account, your pension, or your index fund. For the vast majority of people, it belongs — if anywhere — in the speculative slice of a portfolio: the portion you could lose entirely without it affecting your retirement or financial stability.

That said, it is worth understanding, even if you never use it. Tokenised treasury bills paying 4-5% yield on-chain, with instant settlement and no minimum investment, are a different animal from ICO speculation in 2017. The infrastructure is maturing. JPMorgan is on-chain. Deutsche Bank has an EU-regulated stablecoin. These are not the markers of a technology that is about to disappear.

If you want to explore DeFi, the practical minimum is: understand what you're approving before you click, use a hardware wallet for anything meaningful, start with audited, established protocols (Aave and Uniswap have years of track record), and treat every claimed APY with genuine scepticism — ask where the yield comes from before you assume it's sustainable.

The "code is law" ethos of DeFi means there is no one to call when something goes wrong. That's not a metaphor. It's a design decision. Know that before you start.