JPMorgan says $103 billion yen short could spark deeper slide in USD/JPY

Market impact:

JPMorgan has drawn attention to the danger that a drop below 155 against the dollar might set off a self-sustaining cycle of short covering, given the size of the bank's estimated outstanding bearish yen wagers. If that entire position were to be unwound, dollar-yen could theoretically fall into a range of 142 to 146, representing a notably stronger yen than current market levels.

At the same time, the bank is challenging what it considers excessive market bets on both a GPIF portfolio adjustment and the speed of Bank of Japan interest rate increases. JPMorgan argues that a sustained move well below its assumed band of 155 to 165 is not yet a likely scenario. For yen traders, the situation cuts both ways: positioning risk urges caution on aggressive short yen trades around 155, while JPMorgan's own baseline outlook does not support betting on a much larger yen rally from current levels.

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JPMorgan flags a $103 billion yen bearish bet that could unwind quickly below 155, even though the bank questions whether the rally has much farther to go.

In a note cited by Bloomberg, JPMorgan Chase strategists are cautioning that continued unwinding of yen short positions could fuel further gains if dollar-yen drops below 155. The bank estimates that between 16 trillion and 17 trillion yen (the lower figure equal to about $103 billion) in bearish yen positions remain in the market, and a full unwinding of that amount could theoretically push dollar-yen into a 142-to-146 range.

This caution comes after one of the yen's most dramatic rallies since Japan and the United States stepped in together to shore up the currency in late July. Earlier this week, dollar-yen rose as far as 160.39, the highest since that intervention, before reversing sharply to a low of 155.30 — not far from the post-intervention floor of 155.23.

Strategists led by Junya Tanase noted that recent price action reinforces their assessment that a sizable yen short position may still be present. They warned that a breach of 155 carries the risk that "selling could beget further selling," potentially prompting more yen appreciation than anticipated. Speculation about a possible change in the Government Pension Investment Fund's asset allocation, along with rising expectations for faster Bank of Japan rate increases, have driven the rally. Market observers point out that these catalysts have been amplified by speculative yen short covering and hedging by Japanese domestic investors, creating a risk that additional gains force even more bearish positions to close out.

Even as it flags this risk, JPMorgan is not backing the more aggressive scenarios envisioned by the market. The bank considers current expectations on both the GPIF reallocation and the BOJ tightening pace "a bit excessive" and sees a low probability that dollar-yen will fall significantly below its assumed 155-to-165 range for now. That leaves the bank's near-term view genuinely two-sided: acknowledging real downside risk from a positioning unwind, while stopping short of predicting the deeper, sustained yen strength that a full exit from the estimated short positions would imply.