US Debt Hits 40 Trillion as Yields Spike to Five Percent

US national debt has surpassed 40 trillion dollars for the first time. This milestone coincides with the 30-year Treasury yield breaking above 5.3 percent. The yield reached its highest level since 2007. The US Treasury Department responded by expanding its buyback program for long-dated debt. This move aims to stabilize the market. The primary driver is the rising cost of servicing existing obligations.

Interest costs on government debt exceeded 1.2 trillion dollars in 2025. This amount is a record high. It surpasses the entire US defense budget. Net interest costs reached 18.5 percent of federal revenue. This figure tops the previous peak of 18.4 percent set in 1991. The debt trap is now self-reinforcing. Higher deficits lead to more issuance. More issuance pushes yields higher. Higher yields increase interest payments. Increased payments widen the deficit further.

Buybacks Mask Structural Deficits

The Treasury buyback program initially eased the 30-year yield. The rate dropped from the 5.3 percent range to the 5.2 percent range. The 10-year yield fell by 6 basis points. However, this is a liquidity management tool. It does not reduce the total stock of debt. The Treasury uses its general account or issues short-term bills. This shifts long-term debt into short-term obligations. The share of short-term debt rose to 22 percent. This exceeds the recommended ceiling of 20 percent.

This rollover pattern creates refinancing risks. Short-term debt is vulnerable to rate swings. It can trigger seizures in funding markets. Confidence in the sovereign balance sheet may erode. The AI investment boom adds to the pressure. Private capital demand for data centers and semiconductors competes with public issuance. This dual demand pushes rates up. The structural fix requires reducing the fiscal deficit. Current measures only manage the symptoms.

Korean Fiscal Policy Faces New Pressure

Elevated US rates transmit to Korean bond markets. Upward pressure spreads to government and corporate yields. Volatility in the won-dollar exchange rate increases. Concerns about foreign capital outflows rise. Korea’s economy has many rate-sensitive segments. Household debt and real estate project financing are key areas. The burden is heavier for an economy without reserve currency status. Korea must manage fiscal credibility more strictly than the US.

Korean authorities must monitor global capital flows closely. They must manage foreign currency liquidity of financial institutions. The maturity structure of external debt requires attention. Authorities must preemptively reduce risks in vulnerable sectors. This includes household debt and project financing. Building a stronger macroprudential backstop is essential. The US debt trajectory signals a persistent high-rate environment. Korea cannot rely on easy monetary conditions. Prudent fiscal management is the only stable path.

Market Signals Warn of Structural Shift

GN auto markets/bonds: sovereign debt data confirms the trend. The 40 trillion dollar debt level is not a temporary spike. It is the result of decades of accumulated deficits. The US Treasury cannot easily return yields to historical lows. A higher-for-longer phase is likely. Global markets are adjusting to this new baseline. Investors are demanding higher compensation for risk. The era of cheap money is ending. Fiscal discipline must replace reliance on market liquidity.

The warning is clear for all sovereign borrowers. Debt service costs are no longer a secondary concern. They are a primary driver of fiscal policy. The US experience provides a direct template. High debt levels constrain future policy options. Interest payments crowd out other government spending. The debt trap is now the dominant economic factor. Markets are pricing in this reality. The 5.3 percent yield is a floor, not a peak. Fiscal sustainability is the new metric for creditworthiness.