Global bond markets suffered a severe selloff in September, pushing benchmark U.S. and European government yields to multi-decade highs. The market turmoil was driven by surging energy costs, heavy government borrowing, and rising inflation expectations, which pressured foreign exchange rates and equity markets worldwide.
Treasury Yields Hit Multi-Decade Highs
The yield on the benchmark 10-year Treasury note reached 5.34% during Thursday’s trading session, marking its highest level since 2002. U.S. long-dated Treasury yields climbed to their highest levels in more than twenty years, as a relentless global bond selloff accelerated across international markets. Meanwhile, the yield on 30-year Treasury bonds climbed to 5.48%, representing the highest mark recorded since 2004.
This upward pressure on sovereign debt stems from a combination of persistent fiscal deficits, resilient economic growth, and heavy energy costs. The Iran war disrupted oil flows from the Strait of Hormuz, driving crude prices above $100 per barrel and fueling inflationary concerns across the global economy. In response, central banks face mounting expectations for prolonged monetary tightening, altering the risk premium on long-dated bonds as investors demand greater rewards to offset inflation.
According to data from the Pentagon’s Lead Inspector General, the conflict with Iran cost U.S. taxpayers $33.4 billion through June. Zachary Griffiths, head of investment grade and macro strategy at CreditSights in Charlotte, North Carolina, noted that underlying economic expansion remains strong. Treasury bonds have faced intense competition with the rest of the market for buyers, leaving analysts watching how much higher borrowing rates can climb.
European Markets and Foreign Exchange Rates Face Fiscal Stress
Germany’s 10-year Bund yield briefly climbed above 3.6% to reach a 17-year high, while Japan’s 10-year bond yield hit its highest level since 1996. The debt selloff extended far beyond American shores, sending severe strains through European and Asian sovereign bond markets. Global bonds registered their largest monthly decline in years during September, pressured by deteriorating government finances, a heavy issuance glut, and rising inflation.
In foreign exchange trading, the U.S. dollar surged to a 17-month high against the euro. The European currency fell below $1.1215 for the first time since May 2025, closing down 0.77 per cent at $1.12433 against the dollar. Brian Daingerfield, head of G10 FX strategy at NatWest Markets, observed that higher yields stem from a confluence of factors, particularly fiscal policy concerns and weakness in French bond markets that spilled over internationally. Amo Sahota, director at Klarity FX, pointed to market panic in European markets as a primary driver. Meanwhile, the Australian dollar dropped to a three-month low of $0.69040 following domestic inflation readings that fell short of forecasts, and sterling slid 2.1 per cent over the prior month.
Consumers and Corporate Borrowers Face Squeezed Wallets
Fixed-rate 30-year mortgages in the United States surged alongside longer-term Treasury debt, while the U.S. economy added 29,000 jobs in September at a slower pace than anticipated.
The most immediate effect is typically through adjustable-rate debt, such as credit cards, home equity lines of credit, and adjustable-rate mortgages.
Brian Therien, senior analyst at Edward Jones
Therien advised consumers weighing new loans to prepare for elevated rates and monthly payments, noting that borrowing costs may act as a headwind by tightening credit conditions for households and businesses. Richard Saperstein, chief investment officer at Treasury Partners, cautioned that equities could react unfavorably if the 10-year Treasury yield climbs above 5.25%. Conversely, higher rates provide certain benefits to savers, as high-yield savings accounts, certificates of deposit, money market funds, and fixed-income assets generate increased income for individuals and long-term investors.