What Is a Stablecoin?

A stablecoin is a crypto token engineered to hold a fixed value, almost always one US dollar. It's the answer to an obvious problem: everything else in crypto moves violently, and you can't price, save, or settle in an asset that might be worth a fifth less by the weekend. Stablecoins are the market's working currency. Most trading pairs quote against them, most DeFi lending is denominated in them, and in countries with weak currencies they've quietly become a dollar account you can hold on a phone. By transfer volume they are arguably crypto's clearest success story. They are also the site of one of its worst disasters, and the difference between the two comes down to one question: what actually backs the peg?

The three designs, and how much to trust each

Fiat-backed. Tether (USDT) and USD Coin (USDC) dominate here. A company holds reserves, cash and short-term treasuries, and mints one token per dollar held. The peg holds because the issuer stands ready to redeem, and the risk is exactly where you'd guess: you're trusting a company's balance sheet and its auditors. These are, bluntly, custodial IOUs on a blockchain. They also work, at colossal scale, and have for years. The residual risks are reserve quality (a question Tether spent years answering vaguely), regulatory action, and the issuer's freeze switch. Most fiat-backed stablecoins can blacklist addresses, which cuts both ways depending on whether the frozen party is a hacker or you.

Crypto-collateralised. DAI is the canonical example: users lock crypto collateral worth substantially more than the stablecoins they mint, and automated liquidations defend the buffer. No single company to trust. Instead you're trusting smart contracts, price oracles, and the collateral itself staying orderly in a crash. More transparent than the fiat model, more moving parts, and a solid track record through some ugly markets.

Algorithmic. The peg is defended by a mechanism, typically a twin token that absorbs volatility, rather than by collateral. We'll skip the theory and go straight to the case study. TerraUSD (UST) was the largest algorithmic stablecoin ever built, its system was worth around $40 billion, and in May 2022 it unwound to zero inside a week, taking its twin token LUNA with it and lighting the fuse on that year's cascade of failures. The design has a death spiral built into its floor plan, and every large-scale attempt has ended the same way. Our view is not nuanced: treat "algorithmic stablecoin" as a warning label, not a category.

What "stable" doesn't cover

Even the good designs wobble. USDC traded meaningfully below a dollar for a weekend in March 2023 when part of its reserves was caught in Silicon Valley Bank's collapse. The peg recovered, but the lesson stands: a stablecoin is only as calm as its backing during a panic. Depegs, issuer risk, contract risk, and freeze risk don't show up in the price chart until the day they're the whole chart. A stablecoin is a fine place to park between trades and a reasonable working balance. It is not a savings account, it carries no deposit insurance, and holding your entire net worth in one issuer's token is a concentration bet dressed up as caution. Yield offered on stablecoins deserves the same question as all yield: where does the money come from? If the answer is fuzzy, the yield is the bait.

Practical notes

On our coin pages you'll spot stablecoins instantly: price pinned near a dollar, volatility near zero. That flatness is also why we deliberately publish no price forecasts for them. Our model excludes pegged assets, since "prediction: one dollar" is noise dressed as insight, and the interesting risk in a stablecoin (the peg breaking) is exactly the kind of tail event a volatility model shouldn't pretend to time. Hold them for what they are: a tool for stability with counterparty strings attached, in a market that keeps proving the strings are real.

Frequently asked questions

What is the safest stablecoin?

The large fiat-backed coins with audited, treasury-heavy reserves (USDC is the usual answer) have the cleanest backing story, with USDT the volume king and a longer history of reserve questions. "Safest" is relative: every stablecoin carries issuer, regulatory, or contract risk that a bank deposit doesn't.

Can a stablecoin lose its peg?

Yes, and the record proves it in both severities. USDC dipped below a dollar for a weekend in 2023 and recovered; TerraUSD went to zero in 2022 and did not. Collateral quality decides which kind of depeg you're exposed to, which is why the backing is the only question that matters.

Why do people earn interest on stablecoins?

Because borrowers pay to borrow them, mostly traders wanting leverage without selling assets. That lending yield is real but not risk-free: you're taking on the platform's contract or solvency risk. Rates far above what lending markets pay mean extra risk is hiding somewhere in the pipe.