The flash crash

A few months ago the US share market plunged l000 points in a few minutes, and trillions were traded both up and down. What caused it, and can it happen again. Tiny high frequency computer algorithms - or algos - roam the markets, buying and selling in a parallel universe more or less uncontrolled by anyone. Did they go feral, or was it the fat finger of a coked out trader? In September US regulators bring out their findings. Reporter Stan Correy. Photo: Timothy A Clary, AFP.