.IF THERE IS one iron legislation of money management, it is that any sort of program which shows up to create major, trustworthy profits is hiding some similarly large dangers. Past is packed with examples of such money-spinners coming to be wildly popular, merely for supporters to belatedly become aware that they can produce sudden losses as well as consistent gains. Must that push bunches of people to desert identical trades at the same time, the knock-on effects may threaten all type of other resources, and even the financial body on its own. Consider the huge bank on subprime mortgages that anticipated the worldwide financial situation of 2007-09. The current instance is the Oriental yen "bring exchange", the relaxing of which has been roiling markets because mid-July while swiftly raising the worth of the yen. What is a hold exchange, and how can it unwind thus strongly?