USDT

USDT (Tether) is the oldest and largest US dollar stablecoin — the dominant settlement asset on-chain, consistently $100B+ in circulation and routinely outvolumes Bitcoin on a daily basis. Issued by Tether Ltd., a Hong Kong / British Virgin Islands company with a famously opaque history: for years it claimed 1:1 dollar backing while actually holding commercial paper, loans, and other assets; a 2021 NYAG settlement forced disclosures; reserves are now mostly Treasuries but attestations (not full audits) come from smaller firms than USDC's. Runs on Ethereum as an ERC-20, on Tron (where it's actually most used for cheap transfers), and a dozen other chains. Why it keeps winning despite reputational concerns: network effects in crypto-native trading (every CEX, every DEX pair), cheaper fees on Tron for remittances, and pragmatic tolerance from the industry. If USDT ever actually broke peg at scale, it would take a big chunk of crypto down with it — a systemic risk nobody loves talking about.