G7 debt costs balloon as bond yields hit multi-decade highs

Long-term government bond yields across the Group of Seven nations have risen to their highest average levels since 2008, according to Fitch Ratings, adding billions of dollars in debt-servicing costs to already strained public finances and reshaping the investment landscape for sovereign debt.

The surge comes as developed-market government debt is projected to reach a record $75.8 trillion by the end of 2026 — equivalent to roughly 104% of GDP — up $4.2 trillion from last year alone, Fitch said in a July report. Most G7 nations are now at or above the 100% debt-to-GDP threshold, with Germany the notable exception due to its constitutional limits on deficit spending.tradingview+3

US Debt Crosses $40 Trillion

The United States sits at the center of the shift. The gross national debt officially crossed $40 trillion for the first time on August 18, according to Treasury Department data, reaching $40.047 trillion. Annual net interest payments are projected to hit $1 trillion in fiscal year 2026, according to the Committee for a Responsible Federal Budget, making interest one of the largest items in the federal budget.foxbusiness+3

The yield on 30-year US Treasury bonds reached 5.31% on August 17, the highest level since June 2007, CNBC reported. As of late August, the 30-year yield remained elevated above 5.19%.cnbc+1

Pressure Spreads Across the G7

The United Kingdom faces similarly uncomfortable conditions. The 30-year gilt yield reached 5.78% by late August, while net debt interest for 2026/27 is estimated at £109 billion. France confronts projected debt-servicing costs of around €59 billion in 2026, and Italy is on a trajectory where interest payments could consume roughly 9% of government revenue by 2028. Japan's long-term yields are approaching 30-year highs as borrowing cost pressures spread across borders.slguardian+2

Across the G7, interest payments have exceeded defense spending in most member nations since 2024.tradingview+1

A Shifting Calculus for Investors

For institutional investors, the yield environment presents a changed calculus. After more than a decade of historically low rates that diminished the appeal of government bonds, yields above 5% on long-dated Treasuries now offer a competitive alternative to equities for pension funds, insurers, and endowments. For governments, however, the same yields represent a growing financial obligation — as existing debt matures and is refinanced at higher rates, borrowing costs rise even without new spending.tradingview+1

Fitch described the yield spike as highlighting "persistent fiscal challenges" across developed economies. Italy's debt trajectory remains a particular flashpoint, given its status as the eurozone's third-largest economy and the periodic strain its finances have placed on the single currency project.slguardian+2