Alcoa Inc. declined 1.4 percent to $12.20

U.S. stocks fell, sending the Standard & Poor’s 500 Index lower for a second day, as mining and energy companies fell after commodity prices erased gains and PepsiCo Inc. led consumer-staples shares lower.

Alcoa Inc. declined 1.4 percent to $12.20 after rising as much as 1.6 percent. The largest U.S. aluminum producer reported quarterly results after the close of trading, becoming the first Dow company to do so. It posted profit of 9 cents a share excluding some items, topping the average analyst estimate of 5 cents, according to data compiled by Bloomberg.

Third-quarter earnings at S&P 500 companies are expected to grow 23 percent from a year earlier, according to a Bloomberg survey. Analysts surveyed see a 35 percent advance in earnings this year compared with 2009.