Tether

No stablecoin comes close to Tether's scale. USDT's supply sits near 190 billion dollars, roughly three-fifths of the entire stablecoin market and the deepest source of liquidity in crypto, quoted against nearly every asset on nearly every exchange. Issued now out of El Salvador under a local digital-asset license, Tether backs the token mostly with US Treasury bills, alongside cash equivalents, secured loans, Bitcoin and gold, and publishes quarterly attestations rather than a full audit. Direct redemption at par is reserved for verified Tether customers who clear full KYC and typically deal in large size; everyone else simply buys and sells at the market price. That two-tier access, plus a long history of questions about reserve transparency, has not dented its dominance. USDT lives on well over a hundred blockchains, from Tron and Ethereum to a long tail of newer chains.