Stocks were mixed in lower volume near midday Monday. The Nasdaq was up 0.1%, while the Dow Jones industrial average was down 0.2% and the S&P 500 slipped 0.1%. Volume was down about 20% on both the Nasdaq and NYSE exchanges. In the stock market today, oil stocks weakened after OPEC said oil prices will remain below $100 a barrel for the next decade. Noble Energy (NBL) led the S&P 500 lower, dropping 7% in huge volume.