What Are Stablecoins and How Do They Maintain Their Peg?

Stablecoins are a category of cryptocurrency designed to do something most crypto assets don't: hold a steady price. While Bitcoin or Ethereum can swing by double-digit percentages in a single day, a stablecoin like USDC or USDT aims to always trade at roughly one U.S. dollar. That stability makes them useful as a resting place for traders moving between positions, and as a practical medium for payments without exposure to crypto's usual volatility.

The most common type is the fiat-collateralized stablecoin, where the issuer holds cash and cash-equivalent reserves, in theory one dollar in reserve for every token issued. Holders trust that they can redeem their tokens for real dollars, and issuers are increasingly expected to publish regular attestations or audits proving those reserves actually exist. This model is straightforward, but it depends heavily on trusting the issuer's honesty and the quality of its reserves.

A second approach is crypto-collateralized stablecoins, which back their tokens with other cryptocurrencies rather than cash. Because crypto collateral is volatile, these systems typically require users to lock up more value than they borrow, a practice called overcollateralization, and use automated liquidations to keep the system solvent if collateral prices fall. This design removes reliance on a bank holding dollars, but shifts the risk toward smart-contract bugs and sharp market crashes.

A third, riskier category is the algorithmic stablecoin, which tries to maintain its peg through code and market incentives rather than holding traditional collateral at all. These systems expand or contract the token supply automatically to push the price back toward its target. The approach has a troubled track record, most notably the collapse of TerraUSD in 2022, which wiped out tens of billions of dollars in value in a matter of days and remains a cautionary tale about designs that rely purely on market confidence.

Despite the risks some designs carry, stablecoins have become one of the most widely used tools in crypto, routinely settling more transaction volume than Bitcoin itself. They serve as the on-ramp and off-ramp for countless trades, a savings tool in countries with unstable local currencies, and increasingly a rail for cross-border payments. Understanding how a given stablecoin maintains its peg, and what could break that peg, is essential before treating any of them as a safe place to park value.