Stocks rifled higher at Thursday’s open on a mix of U.S. and overseas economic news. The Nasdaq stepped out to an early lead, up 0.6%. The Dow Jones industrial average and the S&P 500 each added 0.4%. Trade was soft, down 7% on the Nasdaq and 2% lower on the NYSE, compared to action at the same time Wednesday. The stock market today opened to a mixed bag of economic news.