New York
GERRY O'REILLY wasn't fazed by Brexit. On the Friday morning after the UK voted to leave the European Union, the manager of the world's biggest mutual fund was on the trading floor in Malvern, Pennsylvania, watching numbers flickering on the four screens in front of him. Stocks were down 8 per cent in Europe and 3 per cent in the US. Mr O'Reilly didn't appear stressed. "For what we do, it's not a huge deal," he says. That's because Mr O'Reilly's job at Vanguard Group is to embrace the market, not avoid volatility. Every trading day, he makes sure the US$450 billion Vanguard Total Stock Market Index Fund matches the performance of its 3,600-stock benchmark. That means owning stocks whether...