U.S. stocks ended little changed in a volatile session Wednesday. The Dow Jones industrial average rose 61.75, or 0.2 percent, to 33.301.93. The broader Standard & Poor's 500 index rose 8.76, or 0.2 percent, to 4,183.96. The technology-heavy Nasdaq composite index was virtually unchanged, falling 1.81 to 12,488.93.