U.S. stocks closed higher Monday amid an unexpected stimulus from China's central bank. China's central bank Sunday lowered the reserve requirement ratio for all banks by 100 basis points. The wider-than-expected cut was the People's Bank of China's second reduction in two months, and marks a continuing effort by the world's second-largest economy to combat slowing growth. The Dow Jones industrial average added 208.63, or 1.17 percent, to 18,034.93. The broader Standard & Poor's 500 index rose 19.22, or 0.92 percent, to 2,100.40. The technology-heavy Nasdaq composite index moved up 62.79, or 1.27 percent, to 4,994.60. The dollar gained against currencies of major U.S. trading partners. Light sweet crude oil for May delivery dropped 30 cents to $56.21 a barrel on the New York Mercantile Exchange. Gold futures fell $9.40 to $1,193.70 an ounce.