Stock market news live updates: Stock futures slip as investors assess Q3 earnings

U.S. stocks tumbled in back-and-forth trading Wednesday as a two-day rally spurred by a better-than-feared start to earnings season faltered. The S&P 500 (^GSPC) sank 1.4% after the index gained more than 4% in the past two days, while the Dow Jones Industrial Average (^DJI) shed 275 points, or 0.9%. The technology-heavy Nasdaq Composite (^IXIC)…