U.S. Stock ETFs Down After Alcoa Earnings, Commodities Rout

The SPDR S&P 500 ETF (NYSEArca: SPY) was off 0.6% in premarket action Tuesday as U.S. stocks were set to open down following disappointing earnings from Alcoa and a sell-off in the commodities market. Alcoa started the first-quarter earnings season with a thud. Also, the pullback in crude-oil...