.IF THERE IS one iron regulation of finance, it is actually that any program which shows up to generate major, reputable earnings is hiding some alike huge threats. Past history is packed with instances of such money-spinners becoming extremely prominent, merely for supporters to belatedly realise that they can create quick reductions along with constant increases. Must that force great deals of folks to abandon comparable professions immediately, the ripple effects may endanger all kind of other properties, and even the financial device itself. Consider the enormous bets on subprime home mortgages that anticipated the worldwide monetary crisis of 2007-09. The most recent instance is the Oriental yen "lug exchange", the unwinding of which has been actually roiling markets due to the fact that mid-July while rapidly raising the market value of the yen. What is a bring exchange, and exactly how can it untangle so violently?