Aluminum concern Alcoa ( AA) said its third-quarter continuing operations profit rose year over year, but its shares fell in late trading as the results came in short of Wall Street's estimates. Earnings from continuing operations for the quarter totaled $558 million, or 64 cents a share, a penny shy of the Thomson Financial expectation. On the same basis a year earlier, Alcoa earned $540 million and 62 cents a share. Revenue slipped to $7.4 billion from $7.6 billion last year, but was in line with the consensus target. The company blamed the decline on the exclusion of the soft alloy extrusion business as a result of forming a joint venture with Sapa in June, lower metal prices, seasonality and softness in North America. Shares of Alcoa dropped 2.2% to $38.85 following the report, which was released after the close. In regular trading, Alcoa had gained 3.7%. Along with reporting its numbers, Alcoa's board boosted its buyback program to cover up to 25% of its shares. Previously, the repurchase was for 10% of its stock. Net income for the third quarter was $555 million, or 63 cents, compared with $537 million, or 61 cents, a year ago. The latest results were impacted by several items, including the sale of Chalco, charges associated with planned asset sales and restructuring and higher petroleum and energy costs.