Wall Street slumped in a late selloff on Monday as euphoria over measures to resolve Europe's debt crisis gave way to more cool-headed assessments of how the remedies would be implemented.

The Dow Jones industrial average dropped 221.75 points, or 1.81 percent, to 12,009.36. The Standard & Poor's 500 Index fell 26.09 points, or 2.03 percent, to 1,259.00. The Nasdaq Composite Index lost 44.84 points, or 1.64 percent, to 2,692.31.