What Is a Stablecoin?

A stablecoin is a cryptocurrency built to hold a steady value — nearly always pegged to one US dollar. The two dominant ones are USDT (Tether) and USDC (Circle), which together make up the large majority of the market. They solve a simple problem: how do you hold value or trade in crypto without constantly cashing out to a bank? You sit in a stablecoin instead.

Why stablecoins exist

Crypto is volatile, and moving to and from a bank account is slow. A stablecoin lets you stay on-chain at a stable value — take profit, wait out a dip, or move between exchanges in minutes. That's also why most trading pairs are quoted against a stablecoin (e.g. BTC/USDT).

The main types

• Fiat-backed (USDT, USDC) — the issuer holds reserves (cash and short-term government debt) meant to back each coin 1:1. Soundness depends entirely on those reserves and how transparently the issuer reports them.
• Crypto-backed (e.g. DAI) — over-collateralised with other crypto locked in smart contracts; decentralised, but exposed to its collateral's swings. (DAI's issuer has been rebranding toward the Sky ecosystem and USDS, though DAI remains in wide use.)
• Algorithmic — try to hold the peg with supply rules and incentives rather than real reserves. These are the riskiest: several have collapsed.

What people use them for

• Trading — the quote currency for most pairs; take profit into a stablecoin without leaving crypto.
• Parking value — sit out volatility without a bank round-trip.
• Moving money — transfer between exchanges or wallets in minutes, and across borders cheaply.
• Earning yield — lending/savings products pay interest on stablecoins, but that yield is not risk-free (it comes from lending or protocol risk); a high advertised rate is a warning sign, not a gift.

The risks

• De-pegging. "Stable" means designed to equal $1, not guaranteed to. UST/Luna collapsed to near zero in May 2022 — the definitive algorithmic failure. Even USDC briefly fell to about $0.87 in March 2023 when reserves were caught in the Silicon Valley Bank collapse; it recovered within days once deposits were backstopped, but it showed that even a reputable coin can wobble.
• Issuer / freeze risk. Centralised issuers like Tether and Circle can freeze or blacklist addresses (they do so on law-enforcement requests) — your USDT/USDC can be immobilised in a way that a bank-account balance usually can't be by a private company.
• Reserve / transparency risk — you're trusting that the reserves exist and are liquid; attestations vary in quality by issuer.
• Smart-contract risk — for crypto-backed and DeFi stablecoins, a bug or exploit in the contracts is an added failure mode.

Reduce it by sticking to large, transparent, well-established stablecoins, spreading across more than one, and never assuming any of them is truly risk-free — especially when a yield is attached.

New to where you'd hold one? See crypto wallets, and how stablecoins anchor order types and pairs.