TORONTO (Bloomberg) — Canadian stocks fell for a third day, the longest losing streak in seven weeks, as commodity producers including Teck Cominco Ltd. and Goldcorp Inc. declined with prices of most industrial metals and bullion.

Income funds such as Penn West Energy Trust also slid, dragging down a group of oil and gas stocks. The securities have fallen since Canada announced two weeks ago that it will close a loophole that allows the trusts to escape from paying most taxes.

“The Canadian market is overvalued,” said Gaelen Morphet, who helps manage about $5.3 billion in stocks and income trusts at CIBC Asset Management in Toronto. “We’re at a high-water mark for valuations of a lot of commodity stocks right now. Trusts are still suffering from the announcement.”

The Standard & Poor’s/TSX Composite Index lost 29.81, or 0.2 percent, to 12,279.59 in Toronto. The index last had a losing streak this long in the four days ending Sept. 22.

A measure of raw-materials producers dropped for a third straight day, losing 1.6 percent. Gold, lead and zinc prices fell while copper rebounded.

Teck Cominco plunged C$3.07 to C$78.95. First Quantum Minerals Ltd., a miner of copper in Africa, slid C$3.39 to C$53.64.

Goldcorp, Canada’s second-largest bullion miner, lost 33 cents to C$31.66. Barrick Gold Corp., the world’s biggest, eased 32 cents to C$33.25.

Falling oil prices sent a gauge of energy stocks down 0.9 percent. Crude oil for December delivery closed 0.5 percent lower at $58.28 a barrel, falling for a third day in New York amid speculation that warm weather in parts of the U.S. has reduced fuel consumption.

Penn West Energy slid 88 cents to C$31.85. Canada’s biggest oil and gas trust by output said third-quarter profit fell 15 percent to C$177.8 million, or 65 cents per unit, because of costs associated with its C$3.3 billion acquisition this year of Petrofund Energy Trust.