How Stablecoins Work

Imagine holding a cryptocurrency that never swings 20% in a day. That’s the promise of stablecoins: digital money that acts like cash but lives on the blockchain. In early 2024, over $140 billion was locked in stablecoins, making them the backbone of crypto trading, payments, and decentralized finance.

But here’s what most people don’t realize: not all stablecoins are created equal. Some are backed by real dollars sitting in bank accounts. Others use mathematical algorithms to maintain their peg. And some, as we’ve learned the hard way, were backed by nothing but promises.

The short answer

A stablecoin is a cryptocurrency designed to maintain a fixed value, typically $1, by backing each token with real-world assets or using algorithmic mechanisms. The three main types are fiat-backed (backed by dollars in a bank), crypto-backed (backed by other cryptocurrencies), and algorithmic (backed by software rules rather than tangible reserves).

The full picture

Why stablecoins exist

Cryptocurrencies like Bitcoin are famous for volatility. A coin worth $50,000 one month might be $30,000 the next. This makes them terrible for everyday transactions. If you paid someone 0.01 Bitcoin for a coffee, the coffee shop might receive anywhere from $0.30 to $0.50 depending on what happens that day.

Stablecoins solve this. They’re designed to always be worth $1 (or another fixed amount), giving crypto users the stability of traditional money while keeping the benefits of blockchain: fast transfers, no bank holidays, and programmable money.

How fiat-backed stablecoins work

The most common type is simpler than it sounds. For every stablecoin in circulation, the issuer holds $1 in a bank account. You give them real dollars, they give you stablecoins. You can always trade those stablecoins back for real dollars at a 1:1 ratio.

Tether (USDT) and USD Coin (USDC) are the two biggest. Both claim to hold dollar reserves equal to their circulating supply. The difference lies in transparency: Circle (USDC) publishes monthly attestations from accounting firms showing bank balances. Tether has faced more scrutiny over the years, with a 2021 New York Attorney General finding that Tether’s reserves weren’t fully backed at all times, though the company has since improved its disclosures.

The catch: you’re trusting the issuer. If they don’t actually have the dollars, your stablecoin is worth nothing. This is called counterparty risk.

How crypto-backed stablecoins work

Instead of dollars, these stablecoins are backed by other cryptocurrencies. The most popular example is DAI, created by MakerDAO.

Here’s how it works: you lock up $150 of Ethereum as collateral and borrow 100 DAI (worth $100). If Ethereum’s price drops and your collateral falls below a threshold, the system automatically liquidates your position. This is called over-collateralization: you put in more than you take out, creating a cushion against price drops.

The advantage: no bank account needed, no single company to trust. The math enforces the peg. The disadvantage: you need to lock up more crypto than you borrow, and sudden market crashes can trigger automatic liquidations.

How algorithmic stablecoins work

This is the most controversial type. Algorithmic stablecoins don’t hold any reserves at all. Instead, they use software rules and market incentives to maintain their peg.

The classic design: there are two tokens. One is the stablecoin (say, worth $1). The other is a “volatility token” that absorbs the swings. When the stablecoin trades above $1, the system creates more of them, increasing supply and pushing the price down. When it trades below $1, the system buys back and burns tokens, reducing supply and pushing the price up.

In theory, arbitrageurs profit from these price differences, keeping the peg stable. In practice, it requires constant demand for the system to work. When demand collapses, so does the peg.

The most famous failure: TerraUSD (UST) in May 2022. It was an algorithmic stablecoin that collapsed from $1 to almost nothing within days, wiping out $40 billion in market value. The lesson was brutal: algorithmic stability isn’t stability at all.

Where stablecoins are used

The biggest use case is trading. Crypto traders need a safe place to park money between trades. Instead of converting to dollars (slow, requires a bank), they convert to a stablecoin (instant, lives on-chain). Over $100 billion trades through stablecoins daily.

A growing use case is payments. Some merchants now accept stablecoins because they’re faster than credit cards and cheaper than wire transfers, especially for international payments. Remittances are a natural fit: sending $200 from the US to Mexico costs $15-30 with Western Union but cents with a stablecoin transfer.

DeFi (decentralized finance) runs on stablecoins. Lending protocols, yield farms, and trading platforms use them as the base currency. You can’t build a crypto bank without stable money.

Why it matters

Stablecoins are the bridge between the traditional financial system and the crypto world. They bring $140 billion of real value into blockchain ecosystems. If that number grows to $1 trillion or $10 trillion, it fundamentally changes how money moves.

For individuals, stablecoins offer something banks often don’t: instant global transfers at minimal cost. If you’ve ever waited three days for a wire transfer or paid $25 to send money internationally, stablecoins are a genuine alternative. The catch is you need to understand which stablecoin you’re using and what backs it.

For policymakers, stablecoins are a headache. They’re dollars (or euros, or pounds) but issued by private companies, not central banks. If a stablecoin fails, regular people lose money with no FDIC protection. That’s why regulators are racing to create rules. The EU’s MiCA framework now requires stablecoin issuers to hold proper reserves and get licensed. The US is still figuring out its approach.

Key terms

• Fiat-backed stablecoin: A stablecoin backed by traditional currency (like dollars) held in bank accounts. Each token is supposed to be redeemable 1:1 for the underlying fiat.
• Over-collateralization: Requiring more collateral than the value of the loan, creating a buffer against price drops.
• Algorithmic stablecoin: A stablecoin with no reserves that uses software rules and market incentives to maintain its peg.
• Counterparty risk: The risk that the other party in a transaction (in this case, the stablecoin issuer) fails to meet its obligations.
• Peg: The target value a stablecoin aims to maintain, typically $1.

Common misconceptions

“Stablecoins are risk-free because they’re pegged to the dollar.”

Nothing is risk-free. The peg is maintained by either reserves (which you hope are real) or algorithms (which can fail). In 2022, three major stablecoins (UST, FRAX, and USDD) lost their pegs temporarily. One never recovered. Always check what backs a stablecoin before trusting it with significant money.

“Stablecoins are the same as central bank digital currencies.”

They’re opposites, almost. CBDCs are government-issued digital money. Stablecoins are private company-issued digital money backed by governments. One is official currency; the other is a private IOU that hopes to stay worth $1.

“You can always redeem stablecoins for real dollars.”

In theory, yes. In practice, it depends on the issuer. Some have long wait times, high minimums, or suspend redemptions entirely during market stress. USDC has generally maintained smooth redemptions, but the experience varies by stablecoin and by jurisdiction.