India, Sept. 3 -- The US bond market is under pressure again, with long-term Treasury yields near multi-decade highs. Higher yields are making mortgages and corporate loans more expensive and can also hurt stock valuations. The pressure is especially visible in the 30-year Treasury yield. The yield has moved back toward its highest level since 2007, even after US Treasury Secretary Scott Bessent doubled the size of long-term Treasury buybacks last month.

Washington is now watching Japan closely because Japan is one of the biggest foreign buyers of US government debt. Japan holds about $1.1 trillion in US Treasurys, making it an important source of demand for US government bonds, according to Yahoo Finance. Japan's own bond market is chan...