U.S. stocks close higher on market optimism

NEW YORK, May 21 (Xinhua) -- U.S. stocks ended higher on Tuesday, as investors await heavily anticipated earnings results from Nvidia, which are set for release after the bell on Wednesday.

The Dow Jones Industrial Average rose 66.22 points, or 0.17 percent, to 39,872.99. The S&P 500 added 13.28 points, or 0.25 percent, to 5,321.41, hitting a record high. The Nasdaq Composite Index increased by 37.75 points, or