Tech, materials stocks push Wall St higher

Earnings at S&P 500 companies are expected to have declined 7.7 percent on average in the first quarter, according to Thomson Reuters I/B/E/S. Alcoa, seen as the unofficial start to quarterly earnings season, will post results after the market closes. Oil, which has been a big influence on the stock market this year, was higher ahead of next Sunday's meeting by producers aimed at freezing output.