US equities extended previous losses on Wednesday as global growth concerns continued to dampen market sentiment. Moreover, disappointing reports from Alcoa and Chevron spurred speculation that US companies will announce losses for Q3. Meanwhile, traders remained cautious ahead of US unemployment claims numbers scheduled for Thursday. The S&P 500 Index tumbled 0.63% to close at 1,432.56. All but one sector within the index dropped. The only gainer was financial sector, with Hudson City Bancorp and M&T Bank Corp. advancing 1.61% and 1.70%. Meanwhile, Yum! Brands was the top-gainer, surging 7.50% on reports that its sales in China remained strong despite economic slowdown. At the same time, oil and gas firms as well as basic materials producers created heavy downward pressure on the US stock index. Anadarko Petroleum and Chesapeake Energy Corp. slumped 1.56% and 0.77% amid falling crude oil prices and profit warnings from Chevron. Among basic materials, Bemis and Cliffs Natural Resources sank 1.10% and 2.69%.