Yen’s Brief Spike Leaves Traders on Alert for Intervention

A sudden surge in the yen ensured traders remained on edge over the potential for Japanese authorities to step back into the market after last week’s intervention to curb declines.

The currency strengthened as much as 0.8% to 155.72 per dollar in a thin holiday session in Asia, before retracing most of those gains and steadying just above 157 per dollar. The spike came after Japan likely spent around ¥5.4 trillion ($34.5 billion) last week to support the yen — a warning shot to traders after it had weakened past 160 per dollar.