U.S. Treasury intervenes in yen market to support Japanese currency

The U.S. Treasury informed banks it may intervene in Japan’s yen market and then bought yen on Friday after Tokyo had already stepped into the market, a rare move that pushed Washington into a fast-moving currency fight. The action came as Treasury Secretary Scott Bessent was photographed at Camp David with a notepad reading, “To Do Buy Japanese Yen $5-10 bil,” a vivid sign that officials were prepared to act.

Japan’s intervention on Thursday was described as massive and may have amounted to as much as 5,897 billion yen, or about $59 billion. That scale underscored how much pressure has built on the currency, which has been weakened by interest-rate differentials, growth concerns and expectations that the Bank of Japan may normalize policy cautiously. Market participants have been watching the dollar-yen pair closely because the yen had been trading near multi-decade lows, and any intervention below key levels can be read as an attempt to defend a zone rather than merely smooth volatility.

The Treasury’s move mattered because Washington generally favors market-determined exchange rates and usually frames its currency statements around excessive volatility instead of a target level. Treasury’s June 2025 foreign-exchange report to Congress continued to monitor Japan’s exchange-rate policies under U.S. law, keeping the issue inside the formal U.S. policy framework even before the latest market stress. The signal from Friday suggested a willingness to go beyond language and use the Treasury’s firepower if disorderly moves continued.

For markets, coordinated or parallel intervention from the United States and Japan can change short-term trading assumptions, raise hedging costs and force investors to reassess the path of global assets. It can also shift money between equities and bonds as traders respond to a stronger or weaker yen. Japan had last intervened in July 2024 and also acted in 2022, when it made its first direct yen-buying operation since 1998. That history made the latest action especially notable: it showed that both governments were willing to confront yen weakness directly rather than wait for the market to stabilize on its own.