New York, July 25 (BridgeNews) - U.S. stocks bounced back as buyers stepped in after a three-day sell-off. Still, traders said the rally may not have much staying power, with investors still concerned about the outlook for the economy and corporate earnings. The Dow Jones industrial average ended up 163.58, or 1.60%, to 10,404.70 and the Nasdaq Composite index was up 24.75, or 1.26%, to 1983.99. The S&P 500 was up 18.76, or 1.60%, to 1190.41.