Japan intervened in currency markets Thursday, sending the yen surging as the dollar fell 3% to 158.34, its biggest one-day drop since late 2022. The move came hours before the Bank of Japan (BOJ) policy decision and followed a divided Federal Reserve meeting that left rates unchanged.

Analysts said the sharp decline bore hallmarks of official intervention by Tokyo, which has warned for months of action as the yen trades at 40-year lows. Japanese Finance Minister Satsuki Katayama has reiterated readiness to act, and authorities spent more than $70 billion in April-May interventions.

The yen's weakness, driven by Japan's low rates and concerns Prime Minister Sanae Takaichi wants to suppress borrowing costs, has raised import costs. Analysts question whether authorities will push dollar below 155 yen to show seriousness.