US and Japan Launch Rare Joint Yen Intervention, Halting Currency's 40-Year Slide

The United States and Japan have undertaken a coordinated foreign exchange market intervention to counter the Japanese yen's depreciation to its weakest levels against the dollar in 40 years. This rare joint action took place on Friday, July 31, 2026, and was officially confirmed through statements from US President Donald Trump and Japanese Finance Minister Satsuki Katayama on August 2-3, 2026. The direct entry of the US into the market to support the yen marks the first yen-buying intervention by Washington since the Asian financial crisis in 1998.

The intervention came after the yen had plunged to levels between 160-164 against the US dollar. This prolonged weakness significantly increased the cost of essential imports for Japan, such as energy and food, intensifying inflationary pressures on the nation's economy. US President Donald Trump characterized Washington's involvement as a "signal of friendship" and "good for the world economy," also suggesting that the US would derive financial benefits from the arrangement. US Treasury Secretary Scott Bessent confirmed the joint effort, stating that the yen appeared "very undervalued" and that Washington "will not hesitate to participate in further joint intervention." Reports indicated that Bessent's notes included a plan to purchase $5-10 billion worth of yen. Japanese Finance Minister Satsuki Katayama corroborated the intervention, attributing it to "excessive volatility and disorderly movements" and affirming Japan's readiness for additional measures if needed.

Following the intervention, currency markets experienced significant shifts. The Japanese yen gained as much as 1.4 percent, reaching 155.20 against the US dollar, building on a 3.8 percent surge over the preceding two trading sessions. The USD/JPY pair retreated from above 163 to below 160, and further to approximately 156.34 after the official announcement. Some reports indicated a 4% plunge in USD/JPY to around 157.45. However, the rapid appreciation of the yen immediately weighed on equity markets, causing the Nikkei share average to tumble. Other major currencies also reacted, with the Euro climbing to a 1.5-month high against the dollar and sterling hovering near a two-week top.

The protracted weakness of the yen was primarily driven by the substantial interest rate differential between the US Federal Reserve (Fed) and the Bank of Japan (BoJ). While the Fed maintained its target range at 3.50%-3.75% (or 5.25-5.5% according to some sources), the BoJ kept its short-term policy rate at 1.0% at its July 2026 meeting, the highest level since 1995 after a 25 basis point hike in June. This wide rate gap made the "carry trade" highly attractive, where investors borrow in low-yielding yen to invest in higher-yielding dollar-denominated assets. Japan's heavy reliance on imports for crucial goods like energy and food exacerbated the adverse impact of a weak yen on its domestic economy.

Analysts suggest that while this coordinated intervention may effectively reduce excessive volatility in currency markets, a lasting strengthening of the yen will necessitate more comprehensive structural changes. The short-term effects of the intervention could prove temporary without supportive policy adjustments. Market expectations indicate that the BoJ might implement faster interest rate hikes than currently priced in by markets, potentially leading to further declines in the USD/JPY pair. The US involvement in this intervention signals that a weak yen is perceived as a concern not only for Japan but also for its allies and for US export competitiveness. This implies that market participants are now trading not just against Japan's Ministry of Finance but against the combined policy interests of Tokyo and Washington.