US and Japan confirm rare joint yen intervention

The US and Japan have confirmed a rare coordinated intervention to support the yen, which had fallen to a 40-year low near 164 per dollar. The action, conducted on Friday, marked the first joint yen-buying operation since 1998 and the first coordinated intervention since 2011 Source: CNBC. The yen strengthened to around 155 per dollar on Monday, its strongest level since early May Source: The Guardian. Both sides signaled readiness for further action, with US Treasury Secretary Scott Bessent saying, "We will not hesitate to participate in further joint intervention" Source: CNBC.

Unusual mechanics

The intervention's mechanics were unusual: reports indicated the US Treasury sold euros to buy yen, rather than selling dollars, a move HSBC called "highly unusual — maybe unprecedented" Source: CNA. Analysts said this avoided signaling a desire for a weaker dollar, which could complicate inflation efforts Source: CNA. Japan may have spent as much as $36.58 billion in the operation Source: CNA.

Motivations

Analysts point to concerns over US Treasury markets: Japan is the largest foreign holder of US debt, and a unilateral intervention could force Japan to sell Treasuries, destabilizing the dollar Source: CNBC. The use of the Fed's FIMA repo facility, which allows dollar liquidity without selling Treasuries, was highlighted as a key signal Source: CNBC. President Trump called the move "a signal of friendship" and said the US is "always there for Japan" Source: AP News.

Market impact

Oil prices fell sharply after Trump signaled a potential deal with Iran, with Brent crude down 5% Source: AP News. Asian stocks were mixed, with South Korea's Kospi dropping 5.2% Source: AP News. For bitcoin, the intervention revived carry-trade fears, but CoinDesk noted that bitcoin's correlation with USD/JPY has been negative, suggesting the impact may be limited Source: CoinDesk.