Stocks added ground Friday, with the Dow and the S&P 500 striking their highest levels in five years. But volume backed off. The Nasdaq -- recovering from Friday's Apple-induced stumble -- rose 0.5%. The S&P 500 climbed 0.4% and the Dow Jones industrial average added 0.3%. Volume declined on both major exchanges, according to preliminary data. Energy and tech stocks trended higher, led by Halliburton 's (HAL) 5% gain and an 8% advance by chip