NEW YORK, July 13 (Xinhua) -- U.S. stocks opened higher on Friday as investors digested a slew of quarterly corporate earnings reports.

Shortly after the opening bell, the Dow Jones Industrial Average was up 33.89 points, or 0.14 percent, to 24,958.78. The S&P 500 increased 0.12 points, or less than 0.01 percent, to 2,798.41. The Nasdaq Composite Index increased 2.87 points, or 0.04 percent, to 7,826.79.

Second quarter earnings are expected to increase 20.7 percent from the same period last year. Excluding the energy sector, the earnings growth estimate declines to 16.9 percent, according to the latest statistics released by Thomson Reuters.

Some of the largest U.S. banks reported mixed quarterly results on Friday before the opening bell.

J.P.Morgan Chase posted record second-quarter profit of 8.32 billion U.S. dollars, an 18-percent increase year-over-year. Its trading revenue rose 13 percent to 5.4 billion dollars, exceeding analysts' expectations.

Citigroup reported a stronger-than-expected quarterly profit but its revenue missed analysts' estimate.

Wells Fargo reported lower revenue and profit for the second-quarter, falling short of expectations.

Shares of J.P. Morgan Chase, Citigroup, and Wells Fargo declined 1.21 percent, 3.09 percent, and 3.98 percent respectively.?