U.S. stocks opened sharply lower amid fresh concerns about European sovereign debt.
The Dow Jones industrial average fell 160 points, or 1.3 per cent, to 12,352, while the S&P 500 slid 17 points, or 1.3 per cent, to 1,316. The Nasdaq composite fell 46 points, or 1.6 per cent, to 2,757.
The Toronto Stock Exchange is closed for the Victoria Day holiday.
European markets fell after Standard & Poor's said Saturday that it might lower Italy's debt rating within two years. Investors are also concerned that Spain's government will have more difficulty enforcing spending cuts after a defeat for the ruling Socialist party Sunday. A debt downgrade for Greece also gave investors more reason to fear that the country could require more financial help.
All of the Dow's sub-sectors were lower, except for consumer staples.
Campbell Soup Co. shares rose 4 cents to $35.28 after the company beat analysts' profit estimates and said it expects full-year results at the high end of its forecast, after changing its promotion strategy.
Crude oil was down $2.83 (U.S.) a barrel at $97.27. Gold rose 80 cents to $1,509.70 an ounce.