(BN) BlackBerry Co-Founder Balsillie Sells Stake in Company

(Bloomberg ) Jim Balsillie, who served as co- chief executive officer of Research In Motion Ltd. until January of last year, has cut his 5.1 percent ownership stake to zero, raising concern that he has lost confidence in the company.

Balsillie reported owning zero shares in RIM as of Dec. 31 in a U.S. regulatory filing dated today. Investors who hold an equity stake in a company of less than 5 percent aren't required to disclose when they buy or sell the shares, according to Securities & Exchange Commission rules.

Balsillie had been the third-largest shareholder and helped lead the company during its heyday as a smartphone pioneer and market leader. He stepped down as co-CEO last year, along with Mike Lazaridis, after fumbling product introductions and losing market share to Apple Inc.'s iPhone and Android devices. The company, now known simply as BlackBerry, unveiled a new lineup last month in a comeback bid.

BlackBerry doesn't comment on the holdings of individual shareholders, said Heidi Davidson, a spokeswoman for the Waterloo, Ontario-based business. Balsillie also declined to comment when approached through his assistant and the company.

BlackBerry shares tumbled as much as 7.5 percent after the disclosure before recovering. The stock was up 3.2 percent at $14.43 as of 11:52 a.m. in New York.

Stock Rally

Optimism about the new BlackBerry 10 platform fueled a 58 percent stock rally in the fourth quarter of last year, rewarding investors after years of declines. Since the Jan. 30 unveiling of the new phones, concerns about a slow rollout in the U.S., BlackBerry's biggest single market, have weighed on the stock. While the new Z10 model is already available in the U.K., Canada and the United Arab Emirates, it won't come to the U.S. until next month.

Donald Yacktman, whose $21 billion mutual-fund firm was BlackBerry's fifth-largest investor last year, sold almost half his holdings in the smartphone maker in the weeks before the BlackBerry 10 debut.

Lazaridis, a fellow co-founder who invented the BlackBerry device itself, held 29.9 million shares as of Dec. 31, according to a separate filing today. That was an increase of about 200,000 shares from the end of the third quarter, and gives him a stake of 5.7 percent in the company.