A taxi whizzes by an electronic board in downtown Toronto showing the sharp drop in the TSX on Wednesday. (Robin Rowland/CBC)

The Canadian dollar fell below 80 cents US on global currency markets on Wednesday, while North American stock markets began the day weakly.

The loonie closed at 79.70 cents US, off 2.69 cents US from Tuesday's finish. The dollar hasn't closed under 80 cents U.S. since the middle of June 2005.

The loonie shed 1.38 cents on Tuesday, after the Bank of Canada cut the target for the overnight rate by one-quarter of a percentage point.

The Canadian dollar has been under pressure as investors move back into the U.S. dollar and oil prices continue to retreat.

Light, sweet crude oil for December dropped $5.43 to settle at $66.75 US on the New York Mercantile Exchange.

The U.S. dollar was trading higher against the euro and the British pound.

The S&P/TSX composite index shed 558.92 points, or 5.7 per cent, to end at 9,236.88 points.

The energy sub-index dipped nine per cent on the oil price drop. Petro-Canada was off 10 per cent at $25.41, while Suncor dropped eight per cent to $26.46.

The financial services sub-index fell four per cent, while the gold group lost 14 per cent on a drop of $32.80 US in the price of an ounce of gold to $733.30 US.

On Wall Street, the Dow Jones industrial average fell 514 points to end at 8,519.21, while the Nasdaq composite index shed 80 points to close at 1,615.75. The S&P 500 gave back 58 points, finishing at 896.78.

Global recession worries and weak earnings reports were seen as weighing on equities. On Wednesday morning, aircraft maker Boeing Co. said its third-quarter profit fell 23 per cent due to a machinists strike and production issues.