OTTAWA: Research In Motion shares jumped more than 15 per cent on Thursday after a burst of positive reviews this week by analysts who had been among the beleaguered BlackBerry maker's harshest critics.

Kris Thompson of National Bank Financial upgraded his price target to Can$15, betting that the stock will rise as momentum builds for the launch of RIM's new BlackBerry 10 operating system and two new smartphones.

Jefferies & Co. analyst Peter Misek doubled his price target to Can$10 and upgraded the stock from “hold” to “underperform,” saying carriers testing the devices apparently have “a much more positive view of BB10 than we expected.”

The stock soared to Can$11.77 on the Toronto Stock Exchange. US bourses were closed for the Thanksgiving holiday.

RIM's new devices are aimed at regaining momentum against smartphones from Apple and those using Google's Android operating system.

While most analysts are expecting a March launch for the new smartphones, Thompson predicted they would hit store shelves a month earlier.

He also noted that RIM's subscriber count had crept up to over 80 million global users this past quarter, rebuffing reports of large corporate and government clients switching to Apple's iPhone.

“The new management team is executing by maintaining the BlackBerry subscriber base, managing costs and cash, and seemingly readying a February 2013 BB10 global platform launch,” Thompson wrote in a research note.