TORONTO (Bloomberg) - Canada's main stock index dropped the most in almost seven years, led by oil and metal producers, after concern that the US economy is shrinking spurred a worldwide sell-off in equities.

Suncor Energy Inc. and Potash Corp. of Saskatchewan Inc. led declines among commodity producers. Toronto-Dominion Bank paced a rout in financial shares. Canada's sell-off followed a three percent drop in the MSCI World Index, a measure of global stocks, that wiped out $750 billion of market value around the world.

The Standard & Poor's/TSX Composite Index fell 604.98, or 4.8 percent, to 12,132.14 in Toronto for its worst drop since February 16, 2001. The benchmark has retreated 17 percent from near a record on October 31 to the lowest in 15 months, approaching a "bear market" drop of 20 percent. Trading in Toronto was about 20 percent below the daily average as US stock markets were closed for Martin Luther King Day.

"We're already in a bear market - who cares what the numbers are?" said Peter Hodson, who helps manage about $6.2 billion as senior portfolio manager at Sprott Asset Management Inc. in Toronto. "We would have crashed if the US was open. We could have been down 15 percent today."

Crude oil fell to a month low in New York and gold and copper fell in London. S&P 500 index-futures indicated a four percent to five percent drop for the US benchmark today, said Pierre Lapointe, assistant market strategist at National Bank Financial in Montreal.

Suncor Energy, the second-largest oil-sands miner, decreased C$4.52, or 4.9 percent, to C$88.32 in Toronto Stock Exchange trading. EnCana Corp., North America's biggest natural-gas producer, lost C$2.73 at C$61.30. Petro-Canada, the nation's third-biggest oil and gas company, slid C$3.85, or 7.7 percent, at C$46.15, the most since January 29, 2004.

Potash Corp., the largest maker of fertiliser, declined C$5.93 to C$119.75. Barrick Gold Corp., the world's biggest bullion miner, dropped C$1.32 to C$46.47. Smaller rival Goldcorp Inc. slipped C$2.38, or 6.7 percent, to C$33.02.