Two hundred billion stablecoins: A new structural force to lower short-term interest rates

Author: Beihu

When I first wrote about stablecoins last October, the total market capitalization of stablecoins was only $170 billion. In the following months, the on-chain market heated up, and the U.S. government continuously pushed forward, the total market capitalization of stablecoins has skyrocketed to $230 billion, an increase of 35% in just over six months. To exaggerate a bit, stablecoins have become a paradigm shift that macro research cannot ignore.

Currently, the mainstream stablecoin issuance model is "collateralize $1, issue $1 stablecoin." Issuers use the collateralized dollars to purchase U.S. Treasury bonds and money market funds, with the interest serving as the company's income.

Looking at the two largest, $USDT has a market capitalization of $150 billion, holding nearly $100 billion in U.S. Treasury bonds maturing within three months, plus $20 billion in reverse repos and money market funds; $USDC has a market capitalization of $58.6 billion, holding $24 billion in U.S. Treasury bonds maturing within three months, plus $30.4 billion in reverse repos. Together, these two hold a total amount of U.S. Treasury bonds that is close to that of South Korea.

This aligns with the conclusions of the BIS latest paper, which found that:

(1) Whenever there is a net inflow of about $3.5 billion (2 standard deviations) into stablecoins, it leads to a decrease of 2 to 2.5 basis points in the 3-month Treasury yield within 10 days;

(2) Conversely, when there is an equivalent outflow, the yield can increase by 6 to 8 basis points, showing a clear asymmetric effect;

(3) This impact is mainly concentrated on the short-end yield curve, with almost no effect on long-term Treasury bonds (because they only buy short-term);

(4) $USDT contributes the most to the impact on interest rates, accounting for 70% of the total effect (due to its large volume).

From the perspective of marginal purchases, from Q1 2024 to Q1 2025, $USDT and $USDC together increased their holdings of U.S. Treasury bonds by $35.3 billion, which is on the same order of magnitude as the increases from the UK (+$42.9 billion) and Canada (+$56.8 billion), and the decrease from Japan (-$36.2 billion).

Going a step further, a recent study by NBER recent research delves into the structure of the U.S. Treasury bond market, categorizing players into two main types:

One type is "granular-demand investors," who have term preferences and institutional constraints, including commercial banks, insurance companies, pension funds, mutual funds, money market funds, foreign central banks, and private investors. Their allocation behavior is usually driven by duration matching, liquidity regulatory requirements, or yield targets, and their demand is insensitive to price changes, possessing cross-term substitutability; the other type is "arbitrageurs," mainly composed of hedge funds, broker-dealer market makers, and lead underwriters, who have a strong risk tolerance and are responsible for absorbing market imbalances and taking on risk pricing roles in the term structure, especially active in the short-term Treasury market.

One major conclusion of the study is that in the short-term U.S. Treasury market, the degree of arbitrageur involvement is high and the risk is low, making the market more resilient (interest rates are less sensitive to supply and demand); in the long-term bond market, the risk is higher, arbitrage participation decreases, and prices are more sensitive to supply and demand. To quickly cash out large redemptions, stablecoin issuers can only hold highly liquid and safe assets (such as U.S. Treasury bonds maturing within three months), belonging to the first type of player in the U.S. Treasury market. As the scale expands, stablecoins are forming a new structural force that depresses short-end interest rates.

How do stablecoins affect the money supply in the U.S.? When $1 is converted from a bank account to an on-chain stablecoin, it reduces the classic measures of M1 and M2; however, as a shadow currency, it does not reduce the actual purchasing power in the economy. If stablecoins are used for daily payments rather than just trading and earning interest, their velocity V will be significantly higher than that of traditional currency.

But if 1 Argentine peso is directly converted into a dollar stablecoin, the impact would be substantial.