U.S. stocks opened lower on Wednesday as investors were cautious before congressional testimony by new Federal Reserve Chairman Ben Bernanke that could give insight on the outlook for interest rates and before U.S. oil inventory data. The Dow Jones industrial average <.DJI> was down 7.84 points, or 0.07 percent, at 11,020.55. The Standard & Poor's 500 Index <.SPX> was down 0.89 point, or 0.07 percent, at 1,274.64. The Nasdaq Composite Index <.IXIC> was down 4.13 points, or 0.18 percent, at 2,258.04.