[As the yen surges, Japanese retail investors buck the trend and increase their short positions, with net short positions reaching 3.6 trillion yen] On September 9, Japanese retail investors are betting that the surge in the yen will not be sustainable. Even though the yen has risen to its highest level in months, they continue to increase their short positions. Bloomberg compiled data from the Japan Financial Futures Association and the Tokyo Financial Exchange. Japanese individual investors held an estimated net short position in the yen last week of 3.61 trillion yen ($23.5 billion), higher than in August. Bearish positions on the yen once reached 4.41 trillion yen in July, the highest level since 2015. Japanese retail investors have always preferred to operate against the trend, selling when the yen is strong and buying when it is weak. That's in stark contrast to foreign investors, who have unwinded yen-financed carry trades as the yen surged. Hedge funds have also established positions for further appreciation of the yen, and some funds are even betting that the dollar against the yen will fall below 150 before the end of the year. The Japanese yen has appreciated about 4% against the US dollar this month, once exceeding the 153 mark. Market expectations that the Bank of Japan will further tighten monetary policy, coupled with speculation that Japan's domestic pension funds may adjust their asset allocation, have driven demand for the yen. The yen triggered large stop-loss orders after breaking through several key price levels, further accelerating the rally.