Japan’s long-term government bond yield briefly climbed to 2.93% on Aug. 17, its highest level in 30 years, intensifying concern that Japanese institutional investors could begin repatriation and reduce support for US Treasuries. That pressure is landing as ultra-long US yields are already rising: the 30-year Treasury yield briefly reached 5.31% on Aug. 17, the highest since June 2007, the 20-year yield moved into the 5.3% range for its highest level since October 2023, and the 10-year yield closed at 4.72%, its highest since July 31. Japan is the largest foreign holder of US Treasuries, and JPMorgan said past Japanese demand had helped suppress long-term US yields, a dynamic that may now be reversing as currency-hedging costs erode the appeal of buying US debt. Yields are also being pushed up by the US fiscal outlook, with the budget deficit by July in fiscal 2026 already above the prior full-year shortfall of $1.775 trillion and Fitch projecting deficits of 7.4% of GDP in both 2026 and 2027. A separate headwind is the AI investment boom, which has driven data-center-related financing to $269 billion this year, roughly double last year’s total, increasing competition for long-term capital. Meanwhile, softer producer price and labor data have pulled the two-year Treasury yield lower, contributing to twist steepening in the yield curve. Investors are now focused on the $16 billion auction of 20-year Treasuries on Aug. 19 as a near-term test of demand.