The United States joined Japan in buying yen to contain disorderly currency moves, protect the US Treasury market and prevent Japan’s financial strains spilling into the global economy.
The Japanese Yen strengthened sharply on Monday after Japan confirmed that Washington had joined Tokyo in a rare coordinated intervention to support the currency.
Japan’s Ministry of Finance said it purchased yen alongside the US Treasury on Friday to counter “excessive volatility and disorderly movements” after the currency fell towards a 40-year low near ¥164 against the Dollar. Finance Minister Satsuki Katayama warned that the two countries would not hesitate to intervene again.
At the time of writing, the US Dollar to Yen exchange rate (USD/JPY) was trading around 156.63, down 0.52% on the day. The pair briefly plunged towards 155.27 overnight before recovering, extending its retreat from levels above 163 in late July.
Washington’s involvement was not simply an act of support for a key Asian ally.
Japan had already spent heavily buying yen, with Bank of Japan data suggesting that Tokyo may have deployed almost $59 billion during Thursday’s intervention. Funding further action by selling US government bonds risked driving Treasury prices lower and pushing American borrowing costs higher.
The US intervention therefore helped address two risks at once: a destabilising collapse in the yen and the possibility that Japan could become a forced seller of Treasuries as it raised dollars to defend its currency.
The Federal Reserve’s FIMA repo facility could also allow Japan to obtain temporary dollar liquidity without selling its Treasury holdings outright.
US Treasury Secretary Scott Bessent described the facility as an important backstop and said Washington was prepared to participate in further coordinated action.
The move also supports the Trump administration’s trade agenda.
An exceptionally weak yen makes Japanese exports cheaper and can offset some of the competitive impact of US tariffs, while higher import costs are intensifying inflation and political pressure within Japan.
The intervention has forced traders to unwind large speculative bets against the yen, but officials may struggle to secure a lasting recovery without help from monetary policy.
The Bank of Japan kept its benchmark rate at 1.00% last week, although the coordinated action and increasingly forceful US pressure have strengthened expectations of another increase as soon as September.
For USD/JPY, the immediate risk is now two-sided.
Further intervention could drive the pair back below 155.00, while a failure to follow the currency purchases with tighter Japanese policy could eventually allow the underlying US-Japan yield gap to reassert itself.
Our currency coverage draws on live market data, official economic releases and published bank research.
