The U.S. federal debt crossed the $40 trillion mark last week, with $32 trillion now held by public creditors as deficits approach 6% of gross domestic product, nearly double the level economists consider manageable. The public debt-to-GDP ratio stands at roughly 100%, while interest payments now consume about 3% of annual output, up from 1.5% in recent years.
The shift reflects a structural change in federal borrowing dynamics. From World War II through the late 2010s, U.S. economic growth outpaced debt accumulation, but that relationship reversed following emergency spending during the 2007–2009 financial crisis, pandemic-era relief measures, and the 2017 Tax Cuts and Jobs Act. Aging demographics and the recent reversal of tariffs—requiring refunds to importers—have further strained fiscal balances.
Bond investors are recalibrating expectations as U.S. borrowing costs rise. While Treasury securities remain the global benchmark for risk-free assets, breakeven inflation rates and credit default swap spreads have not spiked, indicating continued confidence in U.S. debt despite higher yields. However, the gap between interest rates and economic growth has narrowed, challenging the long-held view that deficits are sustainable as long as borrowing costs remain below the pace of expansion.
Former International Monetary Fund Chief Economist Olivier Blanchard noted that historically, governments could sustain debt if interest rates stayed below growth rates. That advantage has eroded as structural borrowing costs rise, with the Federal Reserve’s policy rate remaining elevated and the U.S. competing with corporate and foreign demand for global savings.
The rise of artificial intelligence adds another layer of uncertainty. Hyperscalers are increasingly tapping into the same pool of global capital as the U.S. government, sustaining higher interest rates. The technology’s long-term economic impact—including potential disruptions to employment and tax revenues—remains unclear, further complicating fiscal outlooks.
