Wall Street slides as Brexit takes investors by surprise

U.S. stocks fell sharply on Friday, with the Dow Jones industrial average dropping as much as 538 points, as Britain's vote to quit the European Union roiled global financial markets. The S&P 500 index and Dow were on track for their biggest one-day percentage drop since September, while the Nasdaq was headed for its worst day since January. "We're seeing some selling pressure today primarily because a lot of investors and market participants were not anticipating this outcome," said David L