The maker of the popular BlackBerry wireless devices said Thursday that the fourth quarter proved to be unexpectedly strong and subscriber additions are expected to come in higher than previously forecast.

Research in Motion said net subscriber additions are expected to be 15 to 20 per cent higher than the 1.82 million new accounts it predicted on Dec. 20.

RIM 3-month TSX chart

The Waterloo, Ont.-based company said the total BlackBerry subscriber account base is expected to be approximately 14 million at the end of the quarter.

Investors reacted by sending RIM shares up $8.96 to $108 on the TSX.

"BlackBerry smartphones proved to be a big hit throughout the holiday selling season and we're pleased to see RIM's business momentum continuing in the new year," said Jim Balsillie, the co-CEO at RIM.

"The seasonal slowdown in net subscriber account additions that we expected in the new year did not occur and our focused execution with partners has continued to produce strong results within both enterprise and consumer segments," he said in a release issued prior to the opening of stock market trading.

The company said its fourth-quarter revenue and earnings forecast is unchanged from an outlook it gave in December.

RIM said it still sees revenue for the fourth quarter in the range of $1.8 billion US to $1.87 billion. Earnings per share for the fourth quarter are expected to be in the range of 66 to 70 cents US per diluted shares.

RIM is due to report its fourth-quarter financial results on April 2.