NEW YORK, June 1 (Xinhua) -- U.S. stocks dropped in choppy trading on Wednesday as investor sentiment remained shaky on Wall Street.

       The Dow Jones Industrial Average decreased 176.89 points, or 0.54 percent, to 32,813.23. The S&P 500 fell 30.92 points, or 0.75 percent, to 4,101.23. The Nasdaq Composite Index lost 86.93 points, or 0.72 percent, to 11,994.46.

       Ten of the 11 primary S&P 500 sectors ended in red, with financials and health care down 1.67 percent and 1.42 percent, respectively, leading the laggards. Energy rose 1.76 percent, the lone gaining group.

       The above market reactions followed a turbulent May on Wall Street, which saw all the three major indexes suffer a string of negative weeks before a relief rally last week.

       "A week of positive developments is not sufficient to call an end to recent volatility," as "uncertainty remains elevated regarding the outlook for rates, recession, and geopolitical risk," analysts at UBS said in a note.

       "This is a time to focus on investment strategies that are more resilient in volatile markets," they said.

       On the economic front, the Institute for Supply Management said Wednesday that its Manufacturing PMI, a closely followed index of U.S.-based manufacturing activity, rose to 56.1 percent in May from the April reading of 55.4 percent. Any number above 50 percent indicates growth or expansion of the sector.