It is reported that last month, the U.S. Treasury Secretary personally led the inquiry into the yen exchange rate without any request from the Japanese side

The Nikkei reported that U.S. Treasury Secretary Janet Yellen personally led currency inquiries to stabilize the market during the sharp decline of the yen against the dollar last month, despite the Japanese Ministry of Finance neither requesting currency inquiries nor proposing coordinated intervention.

The report indicated that the inquiries were conducted by the New York Federal Reserve on the 23rd of last month at the direction of the Treasury Department, when the yen fell to nearly 158 against the dollar. Yellen was concerned that the political vacuum during Japan's parliamentary elections could trigger broader market turmoil and impact the global bond market. At that time, the yield on Japan's 40-year government bonds first touched 4%, pushing the yield on U.S. 10-year Treasury bonds close to 4.3%.

The report quoted U.S. officials stating that Yellen believed the market misinterpreted signals from the Japanese bond market and was worried that rising global bond yields could undermine overall financial stability