Currently, USDT (Tether) dominates with a $120 billion market cap, while USDC has grown to around $35 billion. Tether’s success is partly due to its focus on emerging markets, where access to USD is limited. In contrast, USDC is more popular in developed markets. However, Circle is expanding USDC’s reach in places like Latin America and Southeast Asia, where it's being adopted for cross-border payments.