The main stock indexes in Canada and the U.S. suffered their worst day of the year as North American markets plunged on growing fears of a global recession.

The S&P/TSX composite index closed down 304.90 points at 16,045.94, for the largest single-day decrease since last October.

In New York, the Dow Jones industrial average was down 800.49 points at 25,479.42. The S&P 500 index was down 85.72 points at 2,840.60, while the Nasdaq composite was down 242.42 points at 7,773.94.

The Canadian dollar traded for an average of US75.13¢ compared with an average of US75.55¢ on Tuesday.

The September crude contract was down US$1.87 at US$55.23 per barrel and the September natural gas contract was down US0.4¢ at US$2.14 per mmBTU.

The December gold contract was up US$13.70 at US$1,527.80 an ounce and the September copper contract was down US3.8¢ at US$2.59 a pound.