Even as the Japanese yen climbs to its strongest level in months, local retail investors are stubbornly betting on a reversal of this sharp rally, continuously adding to their bearish positions. According to compiled data from the Japan Financial Futures Association and the Tokyo Financial Exchange, net short yen positions held by Japanese individual investors were estimated at roughly 3.61 trillion yen (approximately $23.5 billion) last week, marking an increase from August's levels. The bearish yen bets had previously peaked at 4.41 trillion yen in July, the highest reading since 2015.

Japanese retail investors have long favored a contrarian strategy—selling the yen when it appreciates and buying it back when it depreciates. This approach stands in stark contrast to overseas investors, who are now rushing to unwind yen-funded carry trades amid the currency's surge. Hedge funds are also positioning for further yen strength, with some wagering that the dollar-yen exchange rate will fall below the 150 threshold by year-end.

Masayuki Nakajima, senior strategist at Mizuho Bank, noted: "If the yen keeps appreciating, these investors may eventually be forced to close out their dollar long positions." He added that such forced unwinding could, through their dollar selling during stop-losses, further intensify the yen's upward momentum.

So far this month, the yen has strengthened roughly 4% against the dollar, briefly breaking through the 153 level. This move has been fueled by growing expectations of another rate hike by the Bank of Japan, alongside yen buying triggered by speculation over potential shifts in domestic pension fund allocations. The rally accelerated as breaking key technical levels triggered a cascade of stop-loss orders.

However, there are emerging signs that retail investor confidence is beginning to waver as the pace of yen appreciation quickens. Ryo Suzuki, managing executive officer at SBI Liquidity Market Co., observed that retail traders initially bought the dip when dollar-yen retreated from the 160 zone, but grew more cautious after the pair slipped below 155. Although they still maintain a net dollar long position, their buying and selling behavior has become increasingly divergent.

According to Suzuki, current traders are executing stop-losses more decisively compared to the past when they passively awaited forced liquidations. Should the yen strengthen further, it could still compel the liquidation of some remaining dollar long positions.