Stocks added to earlier gains on Wednesday, with the S&P 500 up 1 percent, after an index of factory activity in the U.S. Midwest fell in August, though the figures still pointed to growth in the sector.

The Dow Jones industrial average <.DJI> added 111.33 points, or 0.96 percent, to 11,671.28. The Standard & Poor's 500 Index <.SPX> gained 13.64 points, or 1.12 percent, to 1,226.56. The Nasdaq Composite Index <.IXIC> rose 24.81 points, or 0.96 percent, to 2,600.92.

The S&P 500 was still on track for its worst month since May 2010. After the United States credit rating was downgraded in early August, the index posted one of its worst weeks since the depths of the financial crisis in 2008.