TORONTO (Bloomberg) <\m> Canadian stocks fell on concern a slowing US economy may sap demand for Canadian exports and hit commodity producers’ profits. Suncor Energy and Teck Cominco paced declines as prices for crude oil dropped.The Standard & Poor’s/TSX Composite Index fell 44.64, or 0.4 percent, to 12,829.68 in Toronto, taking its weekly drop to 1.7 percent. It was the second weekly decline in three.

The Canadian benchmark slumped along with global equity markets on March 13, when a report showed US mortgage delinquencies surged, raising the spectre of a housing crisis rippling through the world’s biggest economy. The US takes more than 80 percent of Canada’s exports, which are dominated by energy and metals.

“Tuesday was very ugly,” said John Kinsey of Caldwell Securities in Toronto. “If the economy slows it would not be good for commodities. People have lowered their earnings estimates for energy companies.”

Crude oil for April delivery fell 0.8 percent to $57.11 a barrel in New York, a six-week low, after rising as much as 1.3 percent earlier. Oil prices reversed direction after the US said it will issue a visa to Iran’s President Mahmoud Ahmadinejad so he can speak to the UN Security Council. The US decision eased concern that Iranian oil supply will be curtailed. Oil is down 4.9 percent this week and 10 percent from a year ago.

Suncor, the second-largest oil-sands producer, slipped C$1.34 to C$79.66, extending its weekly slide to 3.9 percent. EnCana Corp., Canada’s biggest natural-gas company, fell C$1.31 to C$53.90. It has dropped 3.6 percent this week. Last month it said fourth-quarter profit dropped 72 percent to $663 million.

Talisman Energy, which produces oil and gas in the North Sea, lost 5.8 percent this week. It fell 47 cents to C$18.51.

Energy companies have been reporting lower profits as oil prices have declined and costs have risen. A measure of energy stocks slipped 0.8 percent today, taking its weekly drop to 2.7 percent, the most among 10 industry groups in the S&P/TSX.

George Vasic, market strategist for UBS Securities Canada in Toronto, cut his 2007 earnings estimate for the S&P/TSX by three percent, citing reductions in energy companies’ forecasts. That would still represent year-on-year profit growth of 13 percent.