New York, May 1 (BridgeNews) - U.S. stocks closed higher as investors began to feel increasingly confident that the economy may have bottomed out and that corporate profits will improve in the second half of the year. The Nasdaq ended up 52.18, or 2.47%, to 2168.42. The Dow was up 163.37, or 1.52%, to 10,898.34 and the S&P 500 was up 17.00, or 1.36%, to 1266.46.