U.S. stocks open higher after upbeat start of Q4 earnings

U.S. stocks opened sharply higher Tuesday following two days of declines, as investors embraced the good start of the fourth-quarter earnings season.

Aluminum giant Alcoa Inc. released strong quarterly results after Monday's closing bell to unofficially kick off the earnings season.

Alcoa said it swung to profit in the fourth quarter of last year as transformation strengthened profitability. The company posted adjusted earnings of 33 cents per share for the past quarter, as revenue jumped 14 percent from last year to 6.4 billion dollars, topping market estimates.

Some major U.S. banks, including J.P.Morgan Chase & Co, Wells Fargo & Co. and Citigroup Inc., will also release their quarterly results this week.

Positive economic data bolstered stocks' rebound. The National Federation of Independent Business said Tuesday that U.S. small business optimism perked up in December, with the Small Business Optimism Index rising 2.3 points to 100.4, the best reading since October 2006.

U.S. stocks were little affected by the continued slide in oil prices, as investors were weighing impacts from positive corporate earnings and economic data against the freefall in oil.

Both Brent crude and U.S. crude dipped to near six-year lows on Tuesday with no sign of production cut from the Organization of Petroleum Exporting Countries.

Shortly after the opening bell, the Dow Jones Industrial Average jumped 239.93 points, or 1.36 percent, to 17,880.77. The S&P 500 rose 23.49 points, or 1.16 percent, to 2,051.75. The Nasdaq Composite Index rallied 60.56 points, or 1.30 percent, to 4,725.26. Endi