Stocks stabbed lower Friday as the Nasdaq joined the S&P 500 in falling under the 200-day moving average . The Nasdaq dropped 1.5%, its third loss of 1% or more during the week. The Dow Jones industrial average and S&P 500 lost 1.2% and 1.1%, respectively. The IBD 50 skidded 1.9%. Volume rose across the board. The Nasdaq punctured its 200-day line one day after the S&P 500 did.