Wall St opens higher as Britain votes on EU membership

Wall Street opened higher for the fourth straight day on Thursday as Britain seemed to swing towards remaining in the European Union, a scenario that would avert a possible financial crisis. Markets across the globe have been rattled over the past two weeks as investors speculated about the consequences of Britain's exit from the European union, including the unraveling of the bloc. U.S. markets also took solace in Fed Chair Janet Yellen's two-day testimony this week when she expressed optimism