Shares in Research In Motion spiked dramatically Thursday after days of steady gains, but analysts were still guarded about the potential success of the BlackBerry maker's new operating system.

On a day when the U.S. markets were closed, shares in Research In Motion surged 17.3 per cent to close at $12, up $1.77, its best performance in months on the Toronto Stock Exchange.

Telecom analyst Troy Crandall predicted, however, that the BlackBerry 10 operating system has only a small probability of successfully taking consumers away from Apple and Android devices when it's released in early 2013.

"It's not that we're super hopeful that this is going to work out," said Crandall, of MacDougall, MacDougall & MacTier.

"There is hope being built in that there's a chance it could work out."

RIM's new BlackBerry 10 operating system -- which will be unveiled at a Jan. 30 event along with its new line of smartphones -- is widely considered a make or break product launch for the Waterloo, Ont., smartphone maker.

Crandall said he doesn't consider it normal that shares in Research In Motion (TSX:RIM) surged 17 per cent in a single day.

"Stocks should not have this type of volatility unless there's something extraordinary going on below the surface," he said.

"I think that's really what you're getting and a lot of that is coming from the short selling and it's magnified by the fact that the U.S. markets are closed."

Investors could be in for a "nasty little surprise" on Friday, when RIM shares will likely go up on New York's NASDAQ exchange, he said. More RIM shares are traded on the NASDAQ, and it's rare for a single stock to rise by 17 per cent on that exchange, Crandall said.

A more modest gain on the NASDAQ will likely pull down the price in Toronto, he added.

He said 95.3 million, or just more than 18 per cent, of RIM's 524 million outstanding shares are held by short sellers, who have essentially bet against RIM and lose money when the company's stock goes up.

"I think a lot of the short sellers are starting to get scared or they're actually just basically cancelling out their position, which means they have to buy it back which adds further upward pressure to the stock."

National Bank Financial analyst Kris Thompson also alluded to short selling. He increased his price target for the BlackBerry maker to US$15 from US$12.

"We think there is more money to be made ahead of the 2013 launch of BB10," Thompson said in a research note.

"Let's reiterate our short-term investment thesis. Buy the stock ahead of the BB10 product launch when we expect shipment estimates to increase, especially from U.S. brokers where a break in negativity could lead to short covering and ongoing stock momentum," Thompson said.

Thompson also noted that RIM's new management team is maintaining the BlackBerry smartphone subscriber base, managing costs and cash, and seemingly readying a February 2013 BB10 global product release, a month earlier than expected.

Thompson said an earlier launch should be beneficial to Research In Motion.

"The shipments boost reflects about one more month of BB10 product availability, plus a little extra for the positive sentiment building in the industry from our discussions."

Thompson said he has increased his estimate of BlackBerry shipments for fiscal 2014 to 35.5 million from 31.6 million, reflecting 4.5 per cent global market share, up from four per cent.

He said certification of the new BlackBerrys by wireless carriers is the key risk to his prediction and estimate of BlackBerry shipments. Carrier certification, which tests the new devices, can take time.

On Wednesday, shares in Research In Motion gained almost five per cent on the TSX even though it was reported that the U.S. National Transportation Safety Board had dropped the BlackBerry maker in favour of Apple's iPhone 5.

Earlier this week, a prominent tech analyst gave RIM's new operating system a small but improved chance of success.

Analyst Peter Misek of New York-based Jeffries & Company said Tuesday that he's still giving the BlackBerry 10 operating system only a 20 per cent to 30 per cent probability of success.