Commodity stocks lift Wall Street at open

U.S. front-month crude held above $50 a barrel a day after surging 7 percent in the wake of the Federal Reserve's plan to pump another $1 trillion into the recession-hit economy. Spot gold prices hit a three-week high earlier and copper prices have surged as the U.S. central bank's plan fanned concerns of U.S. dollar weakness and inflation.

Trading was likely to be volatile as Friday marks the quarterly expiration and settlement of four different March equity futures and options contracts -- a convergence known as quadruple witching.

The Dow Jones industrial average gained 39.74 points, or 0.54 percent, to 7,440.54. The Standard & Poor's 500 Index rose 2.62 points, or 0.33 percent, to 786.66. The Nasdaq Composite Index climbed 7.74 points, or 0.52 percent, to 1,491.22.

(Reporting by Chuck Mikolajczak, Editing by Chizu Nomiyama)