S&P 500 ends unchanged; more carnage in oil stocks

Declining U.S. crude pulled down materials stocks as well as the S&P energy sector , which slumped 2.17 percent. Oil at 12-year lows is stoking fears on Wall Street of deeper losses for energy companies and the potential that some may fail to pay their debts. At the end of a volatile session, a last-minute rally left the S&P 500 up 0.05 percent, barely above a 52-week low hit on Friday.