A trader works at the New York Stock Exchange in New York, the United States, on May 13, 2019. U.S. stocks ended lower on Monday. The Dow fell 2.38 percent to 25,324.99, and the S&P 500 was down 2.41 percent to 2,811.87, while the Nasdaq fell 3.41 percent to 7,647.02. (Xinhua/Wang Ying)