The U.S. and Japanese financial authorities acted jointly to counter the yen’s recent excessive volatility and disorderly movements. Japan’s Ministry of Finance intervened in the foreign-exchange market to buy the yen on Friday, acting in concert with the U.S. Treasury Department. The move marks a clear signal that both nations are determined to bolster the Japanese currency, which has faced steep depreciation as the country struggles with surging energy import costs.

Finance Minister Satsuki Katayama said Monday that the ministry is maintaining close communication with the U.S. Treasury Department and won’t hesitate to intervene again together with its U.S. counterpart. The yen, which slid to a 40-year low against the dollar in late July, strengthened about 1.2% on Friday following a 2.4% gain on Thursday—a surge that fueled market speculation that the Japanese government had intervened to prop up the currency.

Treasury Secretary Scott Bessent emphasized that economic security is national security, adding that the Trump administration is committed to delivering for its trusted partners.