Wall St up as Yellen eases concerns about economy

Wall Street was on track to snap a three-day losing run on Wednesday after comments by Federal Reserve Chair Janet Yellen eased investor concerns about the capacity of the economy to absorb a gradual rise in interest rates. Yellen acknowledged that tightening financial conditions and uncertainty about China posed risks to the U.S. economy, but told Congress she does not expect the central bank to reverse the rate hike programme it began in December. The Fed expects economic growth to pick up in