Stocks opened lower on Thursday as questions remained about the nature of a European deal to help Greece deal with its debt crisis.

The Dow Jones industrial average <.DJI> lost 31.81 points, or 0.32 percent, to 10,006.57. The Standard & Poor's 500 Index <.SPX> fell 4.33 points, or 0.41 percent, to 1,063.80. The Nasdaq Composite Index <.IXIC> dropped 7.27 points, or 0.34 percent, to 2,140.60.