The stock market is run by wild robots we don't fully control

ROBOTS are taking over Wall Street. "Technology has utterly transformed the financial system," says Andrew Lo, an economist at the Massachusetts Institute of Technology. "The vast majority of day-to-day trading is done purely algorithmically." More and more human traders are being shown the door. And researchers like Lo are beginning to find that the more the stock market is run by machines, the less it behaves like one.