Tether's USDT and Circle's USDC together control 85.1% of the stablecoin market, with a combined circulating supply of approximately $257.7 billion. The total market capitalization of all stablecoins currently stands at around $302.9 billion.
USDT is the market leader with a supply of approximately $183.4 billion, representing a 60.5% share. USDC follows with around $74.3 billion, accounting for a 24.5% share of the total market.
The market concentration is measured by the Herfindahl-Hirschman Index (HHI), which is approximately 4244. Since any value above 2500 is considered highly concentrated, the stablecoin sector is classified as such. Other assets like DAI, Ethena's USDe, and World Liberty Financial's USD1 typically hold shares below 3-4%.
Despite its smaller supply, USDC captures between 60% and 70% of on-chain transaction volume. While USDT is widely used in emerging markets and P2P transfers via Tron and Ethereum, USDC is preferred for DeFi protocols and institutional activity due to its compliance and reserve attestations.
In August, USDC saw inflows of roughly $1.5 billion in a single week, contributing to a recovery in overall market capitalization after a contraction in mid-2026.