* TSX rises 27.63 points, or 0.22 percent, to 12,785.44 * Seven of 10 main index sectors advance * RBC has biggest positive influence on the market * BlackBerry up more than 2 percent on buyout speculation By John Tilak TORONTO, Sept 5 (Reuters) - Canada's main stock index advanced for a third straight session on Thursday after positive economic data boosted broad gains across most major sectors and speculation about a potential sale lifted BlackBerry. BlackBerry shares climbed more than 2 percent after a report from the Wall Street Journal said on Wednesday the smartphone maker's board hopes to run a "fast" auction process that could result in a sale of the company by November. The market also processed news that a U.S. Senate committee had approved limited U.S. military intervention in Syria, as well as moves by some central banks to hold interest rates steady. [ID: nL2N0H01MB] Data showed U.S. private employers added jobs in August, and new claims for jobless benefits fell last week. A separate report said the U.S. services sector grew in August at its fastest pace in almost eight years. Investors contemplated the Federal Reserve's next monetary policy move as they looked to Friday's U.S. nonfarm payroll report, seen as a major indicator of the economy's health. "Expectations of immediate tapering in the (Fed's) September meeting might be a little aggressive," said Colin Cieszynski, senior market analyst at CMC Markets Canada. "My suspicion is that you will see them talk about tapering in September, but I don't think they'll actually do anything," he added. It could more likely happen in October, he said. The Toronto Stock Exchange's S&P/TSX composite index was up 27.63 points, or 0.22 percent, at 12,785.44. Seven of the 10 main sectors on the index were higher. Financials, the index's most heavily weighted sector, rose 0.5 percent. Royal Bank of Canada added 0.7 percent to C$65.93 and had the biggest positive influence on the market; Toronto Dominion Bank was up 0.6 percent, at C$90.85. Shares of energy companies reflected gains in the price of U.S. crude oil, adding 0.4 percent. Suncor Energy Inc rose 0.4 percent to C$35.97, and Encana Corp advanced 0.7 percent to C$18.21. But the materials sector, which includes mining stocks, gave back 0.7 percent on weakness in gold producers. Gold mining shares tumbled 1.4 percent as the bullion price weakened. Goldcorp Inc slipped 1 percent to C$31.18, and Barrick Gold Corp lost 1 percent to C$20.19. BlackBerry was up at C$11.52, helping the information technology group gain almost 1 percent.