NEW YORK, Sept 30 (Reuters) - U.S. stocks turned negative on Wednesday, and major indexes fell more than 1 percent after a regional gauge of business activity unexpectedly contracted in September.
The Institute for Supply Management-Chicago business barometer fell to 46.1 in September from 50.0 in August.
Economists had forecast the index at 52.0. A reading above 50 indicates expansion in the regional economy.
The Dow Jones industrial average dropped 128.02 points, or 1.31 percent, to 9,614.18. The Standard & Poor's 500 Index fell 13.94 points, or 1.31 percent, to 1,046.67. The Nasdaq Composite Index slid 30.83 points, or 1.45 percent, to 2,093.21.