Government borrowing costs from the United States to Germany and Japan are sitting at or near multi-decade peaks, driven by worries about inflation, rising interest rates and mounting debt loads. The selloff touches everything from mortgages to corporate borrowing, and a fresh wave of AI-related bond issuance is adding further pressure.
Japan's 10-year bond yield hit 3% on Tuesday for the first time since 1996. Britain's 30-year borrowing costs sit near 30-year highs, and German and French 10-year yields this week reached levels last seen in 2011 and 2008 respectively. U.S. 10-year Treasury yields rose Wednesday to their highest since mid-2023 at around 4.80%.
A renewed rise in oil prices tied to U.S.-Iran tensions is pushing yields higher, because elevated inflation leaves traders braced for more rate hikes. Adding to the pressure, the U.S. debt pile just crossed $40 trillion, while debt as a share of economic output sits at or above 100% across the G7, Germany excepted. A hawkish speech by Federal Reserve Chair Kevin Warsh at the Jackson Hole symposium has also added to traders' rate hike bets.
Why rising yields matter
Bond yields set the tone for borrowing costs across the economy, from government debt to mortgages, student loans and car loans. Rising rates make borrowing and spending less attractive and can slow growth. U.S. 30-year mortgage rates, for instance, have climbed to a one-year high of nearly 6.7% as Treasury yields rose.
Governments face higher costs too as they roll over debt. Britain's interest bill, now almost 4% of output, is roughly double its pre-pandemic decade average and eclipses the country's defence budget, its fiscal watchdog said in March. Higher yields also theoretically make stocks less attractive, though strong earnings have kept equities buoyant so far, and heavily leveraged hedge funds trading across markets could come under pressure as well.
AI borrowing adds to the pressure
A surge in bond sales to fund AI investments is another factor pushing up yields. Analysts point to the laws of supply and demand: a jump in borrowing demand lets lenders charge higher rates. Five of the biggest AI hyperscalers — Alphabet, Amazon, Meta, Microsoft and Oracle — have issued $220 billion of debt so far this year to fund data centres and models, more than double last year's total, according to LSEG data. That borrowing has helped push global corporate bond issuance to a record $4.9 trillion so far in 2026, up 14% from a year earlier.
What policymakers can do
The U.S. Treasury recently announced bond buybacks, which analysts say are aimed at limiting rising borrowing costs; that initially helped stabilise the market, but long-dated yields have since crept back up. Central banks can also step in directly, as the Bank of England did during the 2022 UK mini-budget crisis, and the European Central Bank can buy government bonds to stem a disorderly rise in borrowing costs under its Transmission Protection Instrument, as long as the country under stress complies with EU budget rules.
Many investors say the current rise in yields is orderly and reflects higher borrowing and inflation. Falling oil prices would help in the short term, but longer-term borrowing costs will likely only come down once governments take concerted steps to cut debt or boost growth. Unless they do, bond vigilantes — investors who demand higher compensation to buy government bonds they see as fiscally undisciplined — will stay on alert.
Source: Investing.com (Reuters)
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