US Treasury and Japanese authorities have maintained close coordination on yen support since their July 2026 joint intervention—the first since 1998—when Tokyo deployed over ¥13 trillion alongside a modest US Exchange Stabilization Fund purchase. With USD/JPY trading near 158 amid a 3.7% September US CPI print that widened rate differentials and lifted Treasury yields, Japanese officials including Finance Minister Katayama have repeatedly signaled readiness for further action if the pair tests the 160 level, citing speculative flows and fiscal risks. Market participants monitor upcoming BoJ and FOMC decisions, G20 meetings, and any shift in US Treasury guidance on the yen’s valuation, as sustained dollar strength could prompt renewed verbal or operational coordination while a durable BoJ tightening path might ease intervention pressure.