USD/JPY risks accelerated yen rally if 155 support breaks, JPMorgan warns

JPMorgan strategists, including Junya Tanase, have flagged 155.00 as a pivotal threshold for USD/JPY, warning that a decisive break below the level could trigger a rapid acceleration in yen strength. The bank's view rests on the concentration of positioning and hedging activity around the figure: a sustained move under 155 would likely force short-yen positions to unwind, while options-related flows could magnify the initial move rather than dampen it. USD/JPY has already been under pressure in recent sessions, leaving the pair testing the lower boundary of its recent range. For traders, 155.00 represents both a psychological and structural line in the sand, with a confirmed breakdown opening scope toward lower support zones and a defence of the level potentially prompting a corrective rebound. Broader drivers remain the Federal Reserve–Bank of Japan policy divergence and shifting US rate expectations, with any softening in US yields adding to downside pressure. Yen crosses such as EUR/JPY and GBP/JPY would likely follow USD/JPY lower in a break scenario.