Fairfax Financial Holdings Ltd. and its founder Prem Watsa more than doubled their stake in BlackBerry maker Research In Motion this week and now have an ownership share that's on a par with the former CEOs of the company.

RIM named Watsa to its board when Jim Balsillie and Mike Lazaridis stepped aside as RIM's co-CEOs last Sunday.

Watsa, one of Canada's best-known value investors, and Fairfax increased their holdings to 26.85 million shares, or about 5.12 percent of RIM after the company named a new chief executive.

Watsa had a 2.2 percent stake at the end of September, according to Capital IQ.

A filing with U.S. regulators on Friday shows that Watsa, Fairfax and affiliated companies boosted their holdings by about 14 million shares in two transactions, on Wednesday and Thursday.

Balsillie and Lazaridis, who remain on the board, each have 5.1 percent stakes. U.S. money management firm Primecap Management holds the largest stake at 5.6 percent.

Fairfax chief legal officer Paul Rivett said the investment firm has no intention of buying more shares at this time. He said the purchase paralleled the move by Watsa to join the board earlier this week.

"We think it's a great company" at current market prices, Rivett said.

Shares of Research in Motion jumped 2.2 percent, or 36 cents to $16.62, in morning trading on the Nasdaq.

Thorsten Heins became RIM's new CEO on Monday as the once-iconic maker of the BlackBerry smartphone confronts the most difficult period in its history.

Americans are abandoning their Blackberrys for flashier touch-screen phones such as Apple's iPhone and various competing models that run Google's Android software.

RIM's U.S. market share of smartphones dropped from 44 percent in 2009 to 10 percent in 2011, according to market researcher NPD Group.

The company still has 75 million active subscribers, but many analysts believe the company will lose market share internationally, just as it has in the U.S.

The Waterloo, Ontario-based company was worth more than $70 billion a few years ago but now has a market value of around $8.7 billion.

Analysts have said RIM's future depends on a delayed new software platform.

RIM said last month the new phones deemed critical to the company's future would be delayed until late this year. Heins, formerly a little known chief operating officer, said getting the new phones to market this year is his top priority.