
Stock Market Today, July 15, 2014: U.S. markets slacked on Tuesday after statements by U.S. Federal Reserve Chair Janet Yellen in front of the Senate Banking Committee indicated that some sectors might be overvalued. Biotech and social media shares slumped in the afternoon. The iShares Nasdaq Biotechnology Index ETF (Nasdaq: IBB) slumped by more than 2.5% after Yellen's testimony.