Futures look ugly....

Ahead of the opening bell, Dow futures are down 221, or 2.2 percent, to 9,822. Standard & Poor's 500 index futures are down 27.90, or 2.6 percent, to 1,043.10, while Nasdaq 100 index futures are down 42.00, or 2.3 percent, to 1,770.50.

Tuesday's expected sell-off follows a sharp, late-session drop Monday. The Dow lost 80 points in the last 15 minutes of trading Monday to close down nearly 127 points. The index is now trading at its lowest levels since February.