Thorsten Heins, the chief executive of BlackBerry, will leave the company  following the collapse of a tentative takeover offer from the ailing smartphone maker’s largest shareholder, the company said on Monday.
Instead of purchasing BlackBerry and taking it private, the largest shareholder, Fairfax Financial Holdings, and an unnamed group of institutional investors will invest $1 billion through debentures which can be converted into common shares at a price of $10 a share.
There has long seen skepticism about the ability of Fairfax  to turn its tentative offer, which values BlackBerry at $4.7 billion, into a firm bid. Since Fairfax first made the offer in September, BlackBerry’s shares never rose to its $9 a share price.
John S. Chen, the former chief executive of Sybase, will become BlackBerry’s executive chairman and the acting chief executive.
The cash infusion into BlackBerry will also see the return of V. Prem Watsa, the chairman and chief executive of Fairfax, to the phone maker’s board. Mr. Watsa had resigned after the company announced that it was reviewing strategic options, including a sale, in the fall.
Mr. Heins, a former Siemens executive in Germany, became chief executive in January 2012 after Jim Balsillie and Mike Lazaridis, the longtime co-chairmen and co-chief executives, resigned in the face of a rapid decline in BlackBerry’s business and the failure of its PlayBook tablet computer.
Formerly the head of the company’s handset business, Mr. Heins heavily promoted the new line of BlackBerry 10 handsets as the company’s salvation. They proved, however, to be a commercial failure setting off the company’s collapse.
Mr. Chen led Sybase from 1998 until the company was acquired by SAP of Germany in 2010. More recently, he has been a senior adviser to the private equity firm Silver Lake Partners, which, with Michael S. Dell, recently took Dell private.
It is unclear if the investment by Fairfax will affect an attempt by group that includes Mr. Lazaridis and Doug Fregin, the other co-founder of BlackBerry, as well as Qualcomm, which makes the chips inside BlackBerry phones and the private equity firm Cerberus Capital Management to make a bid for the company. Other companies have also looked into BlackBerry as a potential acquisition although it is not clear if they have any interest in a bid.
