What’s behind the selloff in world bond markets?

Elevated bond yields have driven a selloff in global bond markets, fueled by concerns over inflation, rising interest rates, and ballooning government debt loads. The United States, Germany, Japan, and Britain have seen their 10-year bond yields reach multi-decade peaks, while U.S. 10-year Treasury yields surged to their highest since mid-2023. This trend is also impacting borrowing costs for households and companies, with 30-year mortgage rates hitting a one-year high.

The U.S. debt pile has surpassed $40 trillion, with debt as a share of economic output reaching or exceeding 100% across the G7 group of major economies, save for Germany. A hawkish speech by U.S. Federal Reserve Chair Kevin Warsh at the Jackson Hole symposium has further fueled traders' rate hike expectations. Additionally, a surge in bond sales to finance AI investments has contributed to the upward pressure on bond yields.

Rising yields make borrowing more expensive, potentially slowing economic growth and squeezing both households and businesses. For instance, Britain's interest bill now amounts to almost 4% of output, more than double its pre-pandemic decade average and surpassing the country's defence budget. Higher yields also make stocks less attractive, although strong earnings have thus far kept equities buoyant. Heavily leveraged hedge funds, which trade across various markets, may face increased pressure as well.

Analysts attribute the surge in bond yields to the laws of supply and demand: when the demand for borrowing increases, lenders can charge higher interest rates, pushing up yields. The recent AI investment boom, with five major AI hyperscalers issuing $220 billion of debt in 2026 alone, has also played a role. This has led to a record $4.9 trillion in global corporate bond issuance so far this year, up 14% from the same period last year.

The U.S. Treasury's recent bond buybacks have temporarily stabilized the market, but long-dated bond yields have since climbed back up. Treasury Secretary Scott Bessent maintains that concerns about rising debt and yields overlook the strength of the U.S. economy. Central banks, like the Bank of England and the European Central Bank, can intervene by buying bonds to stabilize markets during times of stress.

However, durable reductions in longer-term borrowing costs will only occur if governments take concerted steps to reduce debt and boost growth. Investors remain vigilant, as bond vigilantes are prepared to impose fiscal discipline on profligate governments by demanding higher compensation.