Traders are grappling with concerns that some European countries might not be able to rein in mounting debt. Stocks have also been hurt in recent weeks by China's plans to limit economic growth and the U.S. government's proposed rules to restrict trading by large financial institutions.

Overseas markets were mixed Monday.

Dow Jones industrial average futures are down 1, or less than 0.1 percent, at 9,940. Standard & Poor's 500 index futures are down 0.50, or 0.1 percent, at 1,059.30, while Nasdaq 100 index futures are down 2.00, or 0.1 percent, at 1,743.00.