Tokyo and Washington have threatened further coordinated moves to contain turmoil spreading from currency markets into bond markets
Japan and the US have officially confirmed an extraordinary joint intervention to rescue the yen after its collapse toward a four-decade low spilled over into the already strained American government-debt market.
Japanese Finance Minister Satsuki Katayama announced the operation on Monday morning in Tokyo, saying the two governments jointly purchased yen during US trading on Friday, July 31.
The intervention was intended to counter “excessive volatility and disorderly movements” in the currency, Katayama said, adding that Tokyo remained in close contact with the US Treasury and “will not hesitate to conduct further joint intervention.”
US Treasury Secretary Scott Bessent issued a nearly identical warning, saying Washington remained prepared to participate in additional joint action. He described the intervention as a matter of both economic security and support for a key American ally.
The operation was the first coordinated US-Japanese currency intervention since the G7 acted following the 2011 earthquake and tsunami. It was also the first time Washington had directly helped purchase yen to strengthen the Japanese currency since 1998.
The yen had fallen to 163.99 against the dollar on July 23, its weakest level since 1986, before suspected Japanese interventions and the subsequent US operation drove it sharply higher. It strengthened to around 156.40 per dollar following Katayama’s statement on Monday.
Tokyo did not disclose which reserve assets it liquidated to support the yen, but the intervention coincided with a sharp selloff in US government debt, strongly indicating that Japan unloaded part of its enormous Treasury portfolio to finance the yen purchases. The benchmark ten-year Treasury yield jumped more than nine basis points on Friday to 4.735%, its highest level since 2023, while the 30-year yield reached 5.265% – a level not seen since the 2007 financial crisis.
Japan remains Washington’s largest foreign creditor, with Japanese investors holding some $1.143 trillion in US government debt in May – already down almost $67 billion from April – according to the latest available Treasury Department figures. Sharp movements in Japanese markets can force investors to rebalance portfolios worldwide, placing upward pressure on US and European government-bond yields.
Tokyo has not disclosed the precise cost of the latest operations, but analysts estimated that Japan may have spent close to ¥8.45 trillion (roughly $53 billion) during Thursday’s initial intervention alone.
Bessent inadvertently revealed the scale of the American contribution when a photographer captured his handwritten to-do list during a cabinet meeting on Friday. The list included an instruction to buy between $5 billion and $10 billion worth of yen.
Washington itself was forced to liquidate some of its euro holdings to support the yen, with the New York Fed selling Europe’s common currency on behalf of the US Treasury – effectively shifting part of the burden of Japan’s rescue onto its European allies.
US President Donald Trump said on Sunday that Japan had asked Washington for “a little bit of help,” arguing that the operation would produce a “financial benefit” for the US and was also “good for the world economy.”
