Stocks rose at the open on Monday, building on the previous week's gains, as optimism grew that an upcoming European Union summit would break new ground to resolve the euro zone debt crisis.

The Dow Jones industrial average <.DJI> was up 107.77 points, or 0.90 percent, at 12,127.19. The Standard & Poor's 500 Index <.SPX> was up 14.66 points, or 1.18 percent, at 1,258.94. The Nasdaq Composite Index <.IXIC> was up 32.96 points, or 1.25 percent, at 2,659.89.