Bond yields soar as fresh U.S.-Iran tensions revive inflation concerns

Government bond yields jumped across major markets Tuesday, with borrowing costs in Japan and the U.K. touching multi-decade highs, and U.S. Treasury yields surging, as renewed Middle East hostilities reignite inflation concerns.

The key U.S. 10-year Treasury note yield moved to a 20-month high, rising 3 basis points to trade at 4.7880%.

Japan’s benchmark 10-year note yield jumped more than 6 basis points, moving to 3% for the first time since 1996. Japan’s short-term 2-year government bond yield also touched a 31-year high of 1.81%.

Elsewhere, yields on U.K. 10-year government bonds, known as Gilts, rose more than 9 basis points to 5.2341%, their highest level since June 2008 in the midst of the Global Financial Crisis. The U.K. 30-year Gilt yield, meanwhile, soared 9 basis points to 5.8856%, its highest level since March 1998.

German government bonds — typically seen as a barometer for euro zone borrowing costs — also rose. The 10-year bund yield was up more than 3 basis points at 3.3546%, a new 52-week high, as the 2-year bund yield reached 2.9496%, its highest level since July 2024. France’s 2-year government bond yield rose to its highest level since April 2024.

Treasury Secretary Scott Bessent shrugged off concerns over rising U.S. yields in an interview with CNBC on Monday.

Speaking on the sidelines of the G20 finance ministers’ meeting in Asheville, North Carolina, Bessent said the U.S. bond market remains “the best performing market” in the world, noting that Fitch Ratings last month reaffirmed its AA+ rating on government debt.

The jump in borrowing costs came after the U.S. and Iran launched retaliatory strikes around the Strait of Hormuz in recent days, driving energy prices higher and putting inflation pressures back on investors’ radars.

Brent crude, the global price benchmark, was last seen about 2.2% higher at $92.38 per barrel, while West Texas Intermediate futures were up 2.61% at $88.05.

Steve Englander, head of global G10 FX research and North America macro strategy at Standard Chartered, said the six-month conflict, combined with a Supreme Court tariff ruling that he said removed roughly 40% of additional tariff revenue, had added to pressure on bonds.

Englander told CNBC’s “Squawk Box Europe” Tuesday that yields across the curve will remain under upward pressure, adding that the U.S. is not alone in facing a deficit problem.

“I think ‘best performing’, as Bessent said, isn’t the same as well performing,” Englander said. “Everybody has a deficit problem — I don’t think there’s any reason to cheer.”

The rise in the cost of British government debt comes as U.K. Prime Minister Andy Burnham is reportedly set to tell lawmakers later that greater public control is the only way to boost the country’s growth.

Burnham, who in July became the U.K.’s seventh prime minister in 10…