A filing with the US Securities and Exchange Commission reveals BlackBerry co-founders Mike Lazaridis and Douglas Fregin may be considering buying back the company they helped to found.

The filing showed Lazaridis has increased his stake in the company to 8 per cent, and at the same time the two have courted Goldman Sachs and Centerview Partners to help "with their review of strategic alternatives".

The two former executives may also seek outside help with purchasing the company. They are considering "a potential acquisition of all the outstanding Shares of the Issuer that they do not currently own, either by themselves or with other interested investors (an 'Acquisition')", accoring to the filing notes. 

Before the filing hit the wire on Thursday, Bloomberg reported that Fairfax Financial Holdings might not be able to find the necessary partners or assets to go through with the $4.7 billion buyout it proposed in September. This had many believing BlackBerry could be sold off in pieces - as previously proposed - instead of as a whole. However with Lazaridis and Fregin stepping in, that may not happen. 

BlackBerry wouldn't comment specifically on the SEC filing or Fairfax news. A spokesman told Cnet: "The Special Committee, with the assistance of the company's independent financial and legal advisers, is conducting a robust and thorough review of strategic alternatives. We do not intend to disclose further developments with respect to the process until we approve a specific transaction or otherwise conclude the review of strategic alternatives."

News of Lazaridis considering a bid for BlackBerry was first reported in September. The executive was said to have approached private equity firms Blackstone Group and Carlyle Group about putting a preliminary offer together. Thursday's SEC filing may indicate further steps for a proposed acquisition. BlackBerry has previously indicated it wants to self by November. 

Lazaridis stepped away from BlackBerry in January with his co-CEO Jim Balsillie, leaving Thorsten Heins to take over reins of the company. As smartphone competition heats up, things have been looking grim for BlackBerry. Last quarter it reported a loss of almost $1 billion in just 90 days and only 3.7 million BlackBerry smartphones sold - along with 4,500 job cuts.