U.S. markets gave up gains from earlier in the day on Tuesday after Federal Reserve Chair Janet Yellen's remarks on the future direction of interest rates. Yellen told Congress, "If the labor market continues to improve more quickly than anticipated...then increases in the federal funds rate target likely would occur sooner and be more rapid than currently envisioned." Gold prices also took a hit after her remarks on concerns investors would leave the precious metal and move into interest-paying assets. Yellen also said she thinks "equity valuations of smaller firms as well as social media and biotechnology firms appear to be stretched." Shares of Facebook (FB) LinkedIn (LNKD) and Groupon (GRPN) are all down. TheStreet's Susannah Lee reports from Wall Street.