TORONTO (Bloomberg) — Canadian stocks fell, led by energy producers including Cameco Corp., as investors speculated uranium shares are overpriced and natural gas futures in New York dropped the most in almost a month.Cameco, the world's largest uranium mining company, dropped after investors sold short a record number of the company's shares in June. EnCana Corp., Canada's largest natural-gas producer, fell for first time in four days.

"Energy producers have had a great run, but the global economy is slowing down a bit and people are considering other alternatives," said Murray Leith, who helps manage C$4.5 billion for Odlum Brown Ltd. in Vancouver, British Columbia. "We're probably overdue for a pullback."

The S&P/TSX Composite Index retreated from a record, falling 158.25, or 1.1 percent, to 14,338.25. Last Friday the benchmark index capped its biggest two-week gain in 11 months.

Cameco declined C$2.81, or 5.3 percent, to C$50.44. Short sellers, who sell borrowed shares in an attempt to profit by buying stock back at a lower price later, are attempting to exploit uranium mania that increased share prices by fivefold at more than 12 mining companies during the past four years. Investors borrowed and sold 22.3 million Cameco shares, or 6.3 percent of the stock outstanding, as of June 15. That's 35 percent higher than a year earlier, according to Bloomberg data.

Among other uranium producers, Denison Mines Corp. declined 4.5 percent to C$12.89 and Uranium One Inc. slumped 4 percent to C$14.79.

Natural gas futures in New York lost 4.4 percent to $6.368 on forecasts for below-normal temperatures and lower demand in US markets.

EnCana lost 2.8 percent to C$65.42. Canadian Natural Resources Ltd., Canada's second-largest gas producer, fell 1.7 percent to C$72.92.

Shares of gold mining companies dropped as bullion prices in New York declined on speculation that the euro's rally against the dollar will stall, reducing the appeal of gold as an alternative investment.

Barrick Gold Corp., the world's biggest bullion producer, lost 1 percent to C$33.28. Alamos Gold Inc. fell 3.4 percent C$6.20.

Eldorado Gold Corp. declined the most in a gauge of S&P/TSX materials stocks after analysts at Merrill Lynch & Co. cut the shares to "neutral." The shares lost 5.7 percent to C$4.97.