http://www.reuters.com/article/2012/05/21/us-trading-blackbox-idUSBRE84K07320120521
"Think of it as a slow-motion flash crash."
"It's hugely risky," says UCL's Treleaven. Imagine, "everything is going fine and they are all trading fine and then you go through some particular event and all the funds lock onto it, and they all go down together."