TORONTO (Reuters) - Canada's main stock index slipped on Monday, with its heavyweight energy companies falling as U.S. crude prices came off two-year highs, while Kirkland Lake Gold Ltd (>> Kirkland Lake Gold Ltd) and Sierra Wireless Inc jumped after analyst upgrades.

* The Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> closed down 65.97 points, or 0.41 percent, at 16,042.12. Declining stocks outnumbered advancers by a 2.4-to-1 ratio.

* The energy group, which accounts for almost a fifth of the index's weight, retreated 2.4 percent. Pipeline company Enbridge Inc (>> Enbridge Inc) was off 2.3 percent at C$46.29 and producer Canadian Natural Resources Ltd (>> Canadian Natural Resources Limited) fell 2.9 percent to C$42.81 and Encana Corp (>> Encana Corp) lost 4.1 percent to C$14.54.

* U.S. crude prices were down 1.9 percent at $57.84 a barrel, while Brent lost 0.2 percent to $63.73, as the planned restart of the Keystone pipeline and uncertainty about Russia's resolve to extend output cuts weighed. [O/R]

* Shopify Inc closed up 1.8 percent at C$144.69. It had traded as high as C$148.97, its highest since being targeted by a short seller in early October, after saying that it processed more than $1 million in sales a minute for its merchants at the peak of Black Friday shopping activity.

* Shares in technology company Sierra Wireless Inc ended 10.8 percent higher at C$29.46 after Raymond James upgraded it to "outperform," citing a recent sell-off and car connectivity design wins.

* Kirkland Lake Gold Ltd (>> Kirkland Lake Gold Ltd) rose 6.5 percent to C$18.80 after Desjardins raised the stock to a "buy" recommendation and increased its price target for the stock to C$24.

* Hudson's Bay Co (>> Hudson's Bay Co) fell 1.2 percent at C$11.17 after the retailer said almost two-thirds of its shareholders supported Rhone Capital's $500 million investment, which is opposed by activist fund Land and Buildings LLC.

(Reporting by Alastair Sharp; Editing by Andrew Hay and Peter Cooney)

By Alastair Sharp