NEW YORK, Sept 1 (Reuters) - U.S. stocks opened lower on Tuesday as ongoing concerns over the strength of the economic recovery looked set to eclipse data expected to show U.S. manufacturing expanded in August.
After a 50-percent run up in the S&P 500 index since early March, analysts said investors were pausing to assess whether the gains are justified by economic fundamentals.
The Dow Jones industrial average dropped 38.39 points, or 0.40 percent, to 9,457.89. The Standard & Poor's 500 Index shed 3.73 points, or 0.37 percent, to 1,016.89. The Nasdaq Composite Index fell 6.92 points, or 0.34 percent, to 2,002.14.