Wall Street pulls back after recent rally

The S&P materials sector fell 1 percent after copper prices touched their lowest in a month, while energy shares slipped with oil prices. Oil and other commodities are all in pullback mode ... and investors are very focused on commodities because they led on the way up," said Adam Sarhan, chief executive of Sarhan Capital in New York. Investors also are bracing for a weak first-quarter profit season, with earnings for S&P 500 companies projected to have fallen 7.1 percent from the year-a