Stocks opened lower on Wednesday after Portugal's sovereign credit rating was downgraded one notch on budget concerns, adding to overseas debt worries.

The Dow Jones industrial average <.DJI> was down 22.52 points, or 0.21 percent, at 10,866.31. The Standard & Poor's 500 Index <.SPX> dipped 3.10 points, or 0.26 percent, at 1,171.07. The Nasdaq Composite Index <.IXIC> dropped 7.69 points, or 0.32 percent, at 2,407.55.

(Editing by Jeffrey Benkoe)