Japan and South Korea conduct rare joint intervention to stabilize yen and won

Japan and South Korea just tag-teamed the foreign exchange market, and the dollar took the hit. On July 30, the two Asian economic powers conducted a rare coordinated intervention, with Japan’s Ministry of Finance buying yen while South Korean authorities sold dollars to prop up the won. The yen jumped more than 3% intraday to roughly 157.8 per dollar, its best single-day performance in nearly two years. The won climbed about 2%, reaching a nine-month high. These two countries almost never do this together. The last time Japan and South Korea jointly stepped into currency markets was 2011, following the Tohoku earthquake. What happened and why it matters The intervention landed during New York trading hours, a deliberate timing choice designed to maximize impact when dollar liquidity is deepest. Japanese authorities sold dollars and bought yen while South Korean officials ran the same playbook for the won. The move reportedly benefited from tacit support linked to US Federal Reserve rate checks. The yen had been trading near 40-year lows heading into the intervention. Japan has been spending heavily to defend the yen throughout 2026, burning through over $73 billion in intervention...