Key Takeaways
After climbing near-continuously since the start of the year, the total market capitalization of stablecoins has surpassed $250 billion.
With a quarter of a trillion dollars worth of stablecoins in circulation, issuers like Circle and Tether are among the largest holders of U.S. Treasuries, and collectively hold nearly 9% of all outstanding government debt.
Reflecting the end of a prolonged crypto winter, the stablecoin market has been growing since October 2023.
Since then, the total supply of all stablecoins has more than doubled from $120 billion to $250 billion today, DeFiLlama data shows.
Tether’s USDt remains the most popular stablecoin, with a market cap of $154 billion. In second place, Circle’s USDC has seen its market cap boom to over $60 billion.
U.S. Treasury Bills make up the majority of reserves for the most popular stablecoins.
For example, T-bills account for roughly 67% of USDt reserves and around 76% of USDC reserves.
The next most significant asset in stablecoin reserves is overnight reverse repurchase agreements. Stablecoin issuers keep repos on hand because they can liquidate them faster to fund redemptions.
While Circle only holds cash and cash-like assets in its reserves, Tether holds a more diverse range of assets, including bitcoin and gold.
According to the Securities Industry and Financial Markets Association (SIFMA), as of May 2025, the total value of all outstanding U.S. Treasuries stood at $28.6 trillion. That means Treasuries held by stablecoin issuers now account for nearly 1% off of the entire market.
With stablecoins adding to the demand for U.S. Treasuries, increased adoption could make borrowing cheaper for the government.
Because Treasury yields are a benchmark for many interest rates, this could lower the cost of credit for households and businesses.
With stablecoins now accounting for a sizable share of government debt demand, their role in the global financial system is no longer peripheral. What began as a crypto-native convenience is now a macroeconomic force capable of moving markets.