U.S. stocks fell, after the Standard & Poor™s 500 Index posted its first back-to-back weekly retreat since October, as the continuing selloff in crude pulled down energy shares before the start of corporate earnings.

Energy shares tumbled 2.8 percent, the most among 10 groups in the S&P 500, as crude dropped 4 percent. Tiffany & Co. lost 14 percent after the jewelry retailer lowered its annual forecast after sales declined during the holiday. SanDisk Corp. fell the most in almost six years after reporting preliminary results below its own estimates.

The S&P 500 slid 0.8 percent to 2,028.43 at 4 p.m. in New York. Losses accelerated after the market™s open as the benchmark gauge fell through its average price for the past 50 days. The Dow Jones Industrial Average lost 93.86 points, or 0.5 percent, to 17,643.51. The Nasdaq 100 Index slid 1 percent as technology shares retreated.

Source: Bloomberg