An Overview of the U.S. Bond Market

The U.S. bond market is the largest in the world, with approximately $58 trillion in outstanding debt out of a total global bond market of around $143 trillion. U.S. Treasury securities are considered the backbone of the American financial system and, consequently, one of the most influential components of the global financial system. They affect mortgage rates, corporate borrowing costs, and even the valuations of stocks and currencies.

The most important point I want to highlight is the relationship between bonds and U.S. debt, as well as their connection to the federal budget. The relationship between the bond market and the U.S. federal budget has become one of the most important financial issues facing the country today. It is essentially a circular relationship in which each side reinforces the other.

1. Debt-Servicing Costs Rise With Yields

When Treasury yields rise, the government’s borrowing costs automatically increase because the Treasury continuously issues new bonds to finance the deficit and refinance maturing debt.

The current figures are striking. Interest costs on the national debt reached $970 billion in 2025 and exceeded $1 trillion in 2026.

Relative to the size of the economy, interest costs are projected to reach 3.3% of GDP, surpassing the previous peak recorded in 1991.

Interest payments on the debt have also reached approximately 18.6% of U.S. federal government revenues this year.

2. Interest Has Become One of the Largest Areas of Federal Spending

Interest costs so far in fiscal year 2026 represent the third-largest category of federal government spending, exceeded only by Social Security and Medicare.

More significantly, interest spending is projected to surpass Medicare spending by 2028 and discretionary defense and non-defense spending by 2038, eventually becoming the single largest federal spending category by 2048.

3. Crowding Out Other Priorities

Every dollar spent on interest is a dollar that cannot be spent on education, infrastructure, defense, or healthcare.

Rising debt and higher interest costs threaten to crowd out opportunities for investment in other important priorities, both in the public and private sectors.

4. The Relationship Between Interest Rates and the Deficit

First: The larger the deficit becomes, the more bonds the government must issue to finance it.

Second: An increase in the supply of Treasury securities, particularly long-term bonds, can push their yields higher, as we are currently seeing with the 30-year Treasury yield approaching its highest level in 22 years.

Third: Higher yields increase the government’s interest costs on newly issued and refinanced debt, which in turn further increases the deficit, creating a continuing cycle.

Net interest on the national debt, currently the fastest-growing component of the federal budget, is projected to more than double from $970 billion in 2025 to $2.1 trillion by 2036.

5. The Impact of Changes in Interest Rates

With total national debt currently standing at approximately $38.5 trillion, even relatively small changes in Treasury interest rates can have major consequences for government interest spending and overall fiscal stability.

Specifically, if interest rates were just one percentage point higher each year than projected by the Congressional Budget Office, interest costs would increase by approximately $3.2 trillion over the coming decade.

Declining Confidence in U.S. Treasuries

Last week, we observed Japan and several other countries selling some of their U.S. Treasury holdings after their currencies came under pressure against the dollar. This coincided with the Bank of Japan beginning to raise domestic Japanese government bond yields after years of near-zero interest rates.

Among the most notable countries that sold U.S. Treasury securities in March 2026 were:

Japan sold approximately $47.7 billion, while China sold around $41 billion, bringing its holdings down to approximately $683–760 billion, their lowest level since 2008.

Other sellers included Luxembourg, Taiwan, Saudi Arabia, India, Canada, and the United Arab Emirates.

One way the United States can respond to Treasury selling is through higher interest rates, although interest-rate policy is also closely linked to inflation and employment.

An increase of 50 basis points in interest rates can have a direct impact on mortgage rates, corporate borrowing costs, stock valuations, and the interest bill paid by the U.S. government itself. This brings us directly back to the relationship between the bond market and the federal budget.

The deeper problem is that this decline in foreign demand is occurring at a time when the U.S. government needs to finance an annual deficit approaching $2 trillion.

Losing historically stable sources of demand, such as Japan, means that the U.S. Treasury market must attract alternative buyers—either domestic American investors or foreign investors who may require higher yields as an incentive to purchase Treasury securities.

Conclusion

The bond market is not merely a measure of investor sentiment toward the U.S. economy. It is also a direct pricing mechanism for the cost of government debt.

As investors lose some degree of confidence because of inflation, the size of the deficit, or political concerns, they may demand higher yields to purchase U.S. Treasury securities. Those higher yields translate directly into a larger interest bill, placing greater pressure on the federal budget and limiting its long-term fiscal flexibility.

This raises an important question: Will foreign demand for U.S. Treasuries continue to decline? And if it does, who will fill the gap—American domestic investors or hedge funds?