ARMONK, N.Y. - IBM released third-quarter results ahead of schedule Wednesday that beat Wall Street's estimates, sending the company's stock, a component of the Dow Jones industrial average, up 6 percent in after-hours trading.

The company, which has one of its largest sites in Research Triangle Park, also reaffirmed its full-year earnings guidance, a strong sign that IBM's core businesses are holding up well despite the deteriorating U.S. economy.

IBM's shares have tumbled 31 percent since July on concerns that IBM's exposure to the financial services industry, which accounts for 30 percent of the company's sales, would hurt results.

IBM rarely reveals its quarterly results early but has done it twice so far this year. In both cases, its stock price was falling and it wanted to reassure investors about the company's health.

IBM said that it earned $2.05 per share in the July-September period. Net income for the period was $2.8 billion, an increase of 20 percent over the same period last year. Sales increased 5 percent to $25.3 billion. It maintained its forecast of at least $8.75 per share in profit in 2008.

The results suggest that the biggest tech companies are still inking sales deals despite tightened spending, analysts said.

IBM shares gained $5.35 to $95.90 in after-hours trading.

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