BlackBerry abandoned hopes of finding a buyer, and instead pegged its future on a $1 billion cash infusion as it shook up top management Monday and named a new chief executive.

The Waterloo, Ontario-based company's announcement comes two and a half months after its largest shareholder Fairfax Financial Holdings Inc. offered to buy the rest of the business and take it private.

Fairfax instead will invest $1 billion in a private placement, and Fairfax boss Prem Watsa will become lead director of BlackBerry.

BlackBerry chief executive Thorsten Heins meanwhile will step down after only 22 months on the job, and will be replaced on an interim basis by longtime technology executive John Chen, a statement said.

"Today's announcement represents a significant vote of confidence in BlackBerry and its future by this group of preeminent, long-term investors," said Barbara Stymiest, chair of BlackBerry's board.

BlackBerry had announced in August after a dismal year that it was looking for a suitor, among other strategic options.

"Today's announcement marks the conclusion of the review of strategic alternatives," the company said.

Social network Facebook, Chinese computer maker Lenovo and investment firm Cerberus backed by two BlackBerry founders as well as chip maker Qualcomm reportedly kicked the tires, but no deals were reached by Monday's deadline.

Chen, a former head of the software firm Sybase, said he looked forward to steering BlackBerry through its "turnaround and business model transformation," but asked for patience.

"BlackBerry is an iconic brand with enormous potential -- but it's going to take time, discipline and tough decisions to reclaim our success," he said.

The son of poor Hong Kong refugees, Chen attended elite American universities and reportedly foresaw the growth in mobile communications in the late 1990s. He positioned struggling database company Sybase as a leader selling business services in that market.

After turning Sybase around, he oversaw its sale to SAP AG for $5.8 billion, and joined SAP until his retirement earlier this year.

Some analysts have said that BlackBerry has fallen so far behind competitors that its only hope is a breakup, which could salvage its software and services operations.

Most reaffirmed that viewpoint after the latest announcement.

"While the $1 billion investment certainly helps, it's like putting a Band-Aid on a knife wound; by itself, it's not going to stop the bleeding," said Anthony Sabino, a business professor at St. John's University in New York.

"Sadly, the more likely prospect is BlackBerry being broken up into its constituent parts, and its more valuable assets, such as its patents and technologies, being sold off piecemeal."

Michael Walkley, analyst at Canaccord Genuity, cited a "difficult competitive smartphone market" and "low probability" that its new BlackBerry 10 platform can return the company to profitability, saying: "We now believe a breakup is more likely than an outright sale and fundamentals will continue to deteriorate over a now-longer public sale process under new management."

BlackBerry shares tumbled 16.35 percent in trade, closing at $6.50.

Others meanwhile sounded a more optimist note, saying the new cash gives BlackBerry breathing room and a higher valuation should another suitor come forward, while also pegging hopes on Chen's track record as a turnaround artist.

"The new management brought in to right the ship will have both a mandate to do so (with a proven track record) as well as more breathing room (with the increased cash reserve)," said analyst Jack Gold of J. Gold Associates.

"I'd expect to see some significant redirections at BlackBerry over the next 6-12 months as the new management takes hold and new business priorities and directions emerge," he said.

BlackBerry helped create a culture of mobile users glued to smartphones, but lost its luster as many have since moved to iPhones or devices using Google's Android software.

In January, BlackBerry unveiled a new platform as it sought to regain lost momentum, but its most recent numbers suggest this has been a spectacular failure.

BlackBerry still has some 70 million subscribers worldwide, but most of these are using older handsets, with the newer devices on the BlackBerry 10 platform failing to gain traction.

In September, the company announced that it was laying off 4,500 staff -- or one third of its global workforce -- after losing $965 million in its last quarter as sales plummeted.