Japan and the United States recently conducted a joint yen-buying intervention, with Japan potentially spending as much as $36.58 billion to strengthen its currency. This action, the first coordinated intervention since 2011, aimed to prevent a continued selloff in the yen and Japanese government bonds (JGBs) from creating global market instability, particularly by adding upward pressure on rising U.S. Treasury yields. The yen saw a brief surge of over 1% against the dollar, reaching 155.20, after hitting a 40-year low near 164 last month. Analysts, however, warn that while the U.S. involvement added credibility and led to significant short-covering, the intervention itself may only offer a short-term boost if Japan does not address underlying structural issues.
Washington's support for the intervention was motivated by several factors. A key concern was to avoid a scenario where Japan, the largest foreign holder of U.S. government debt, would need to sell large quantities of Treasuries to finance unilateral interventions. The emphasis on the Federal Reserve's FIMA repo facility allows foreign central banks to obtain dollar liquidity without outright selling Treasuries, thereby easing potential funding pressures and preventing destabilization of U.S. Treasury markets. Some analysts suggest that the U.S. Treasury, by selling euros to buy yen, aimed to maximize the signaling effect of the intervention. U.S. Treasury Secretary Scott Bessent explicitly stated strong support for Japan's efforts to correct the yen's "substantial undervaluation."
Despite the immediate impact, many analysts believe the intervention is merely a "band-aid fix." Industry veterans and economists, such as Mark Sobel and Louise Loo, stressed that sustained yen strength requires Japan to address its accommodative monetary policy, large debt load, and potential for further fiscal stimulus. The Bank of Japan (BOJ) kept rates on hold but signaled a potential hike as early as September, leading to a rise in the 2-year JGB yield to its highest since 1995. While intervention can buy time, long-term stability depends on tighter Japanese monetary policy rather than repeated market interventions. Robin Brooks of the Brookings Institution questioned the long-term effectiveness, suggesting intervention might shape the next few months, but BOJ normalization and hedging flows will determine the yen's trajectory over the next few years.
