The stock market came off session lows but still traded sharply lower in afternoon activity Friday. The Nasdaq was down 0.8% and the S&P 500 shed 0.9%. The Dow Jones industrial average lost 1.1% as IBM (IBM) swooned 2.5%, deepening a drop below the 50-day moving average. Volume on both exchanges was tracking 6% higher than Thursday’s pace, which added to the bearish tone of the stock market today.