Wall Street opens flat; Yellen comments awaited

NEW YORK (Reuters) - U.S. stocks opened flat on Tuesday, with the Dow and S&P 500 holding near record levels ahead of testimony by Federal Reserve Chair Janet Yellen.

The Dow Jones industrial average fell 16.18 points, or 0.09 percent, to 18,100.66, the S&P 500 lost 1.1 points, or 0.05 percent, to 2,108.56 and the Nasdaq Composite dropped 4.97 points, or 0.1 percent, to 4,956.01.

(Reporting by Ryan Vlastelica; Editing by Paul Simao and Nick Zieminski)