S&P, Dow hold gains even as Yellen paints bleak picture

The S&P and the Dow held on to gains on Tuesday even as Federal Reserve Chair Janet Yellen warned of a slower pace of economic recovery and global risks including Britain's possible exit from the European Union. The Nasdaq was little changed as biotech stocks weighed. "The pace of improvement in the labor market appears to have slowed more recently, suggesting that our cautious approach ... remains appropriate," Yellen told the Senate Banking Committee.