USDT

USDT, also called Tether, is a fiat-backed stablecoin pegged to the US dollar and issued by Tether Limited. It is the oldest major stablecoin, launched in 2014, and for years it has been the largest by circulating supply and by trading volume, serving as the default dollar substitute on many exchanges worldwide.

USDT exists on many blockchains — including Ethereum and Tron — so the same dollar-pegged token can move over whichever network is cheapest or most convenient. A concrete example of its role: on many exchanges, altcoins are quoted primarily against USDT rather than against actual dollars, so a trader selling a token typically receives USDT and holds it as their cash position. It is also heavily used for dollar savings and transfers in countries with unstable local currencies or limited banking access.

Tether maintains the peg by holding reserves — reported as mostly short-term US Treasury bills and other assets — and by redeeming tokens for dollars for verified customers. The company has faced long-running scrutiny over reserve transparency, including a 2021 settlement with the New York Attorney General over past misstatements about backing, and it publishes quarterly attestations rather than full audits. A common misconception is that USDT's size makes it risk-free; its risk profile depends on reserve quality, redemption access, and the issuer's standing with regulators, not on market share.