(Updates prices, adds analyst comment)
* TSX up 112.86 points, or 0.75 percent, to 15,185.69
By Solarina Ho
TORONTO, May 21 (Reuters) - Canada's main stock index rebounded on Thursday, lifted in part by a general upbeat tone among investors and higher crude prices that bolstered energy stocks for the third straight session.
Valeant Pharmaceuticals International was by far the most influential individual gainer on the index, rising 2 percent to C$284.20. The company is in talks to buy Egyptian drugmaker Amoun Pharmaceutical Co, according to a Bloomberg report on Wednesday.
Other influential movers on the index included Enbridge Inc , which rose 1.72 percent to C$62.12, and Canadian Natural Resources, which advanced 1.7 percent to C$38.59.
The overall energy sector climbed 1.9 percent, tracking higher oil prices, which rose on expectations the excess global crude supply was starting to ease. Fighting in Iraq, OPEC's second-largest producer, also pushed up prices.
U.S. crude was up 2.3 percent to $60.33, while Brent crude added 2.0 percent to $66.32.
At 10:34 a.m. EDT (1434 GMT), the Toronto Stock Exchange's S&P/TSX composite index rose 112.86 points, or 0.75 percent, to 15,185.69.
"Generally, stocks tend to firm up around Memorial Day weekend - people covering their shorts, going flattish to maybe long a little bit here," said Irwin Michael, portfolio manager at ABC Funds, referring to the upcoming U.S. holiday on Monday.
"Bond markets are showing some stabilization ... Generally the news is positive, the least path of resistance to the upside right now. On balance, the glass tends to be half full."
Among the index's 10 biggest groups, only the tech sector was in the red, dragged more than 2 percent lower by Open Text Corp's 12.7 percent decline to C$52.16 after the company gave a lower-than-expected outlook.
Meanwhile, Shopify Inc shares surged on its first day of trading in Toronto and New York. The Canadian e-commerce software maker priced its initial public offering at $17 a share and the stock rose to a high of C$35.03 in Toronto and touched a high of $28.70 on the New York Stock Exchange.
Other influential advancers include Royal Bank of Canada , which rose 0.9 percent to C$80.34 and Canadian Pacific Railway Ltd, which was up 2.0 percent to $216.27.
The financials group climbed 0.6 percent, while the industrials group rose 1.0 percent.
Advancing issues outnumbered declining ones on the TSX by 173 to 70, for a 2.47-to-1 ratio on the upside. (Editing by W Simon)