日元套息交易平倉

It is because the investors have borrowed huge amount of low interest rate yen then sell them in the foreign exchange market to convert it to AUD, NZD or USD..... This is called CARRY TRADE. Then, they make use of those currencies to buy shares. Now, as the world stock markets collpase, they will sell the stock, realize the profits and sell the respective currencies to buy yen for repaying the yen loan, this create huge yen demand, thus yen appreciating.

2007-08-05 13:50:26 補充：
Those traders will borrow yen from Japanese banks e.g. Mizuho, Bank of Tokyo-Mitsubishi..... to get yen for financing their high yield investments. Sell yen and buy foreign currencies, yen will depreciate. Conversely, buy back yen for repaying the yen loan, yen will appreciate.