US stocks opened slightly higher on Wednesday as a rise in oil prices helped energy shares and ahead of Federal Reserve Chair Janet Yellen's testimony before a Congressional committee.
The Dow Jones industrial average was up 34.11 points, or 0.19 per cent, at 18,262.41, the S&P 500 was up 3.47 points, or 0.16 percent, at 2,163.4 and the Nasdaq composite was up 6.41 points, or 0.12 percent, at 5,312.12.