It has emerged that former Research in Motion (now Blackberry) co-CEO Jim Balsillie sold his remaining stake in the firm he founded at some point during 2012.

A Securities and Exchange Commission filing shows that as of December 31, 2012 Balsillie no longer held any shares in the company. A similar filing from one year earlier shows that he owned 26.8 million shares as of December 31, 2011.

Balsillie was co-CEO of Blackberry, joining the firm in 1992 to take the reins along with founder Mike Lazaridis. The firm had fewer than ten employees at the time.

However, in January 2012, both Balsillie and Lazaridis, resigned from their positions, and were replaced by the chief operating officer Thorsten Heins.

Although Balsillie kept his position on the firm’s Board of Directors, in March 2012, Blackberry announced that he would be stepping down from that role.

Balsillie reportedly wanted to continue the existing strategy, while new CEO Thorsten Heins said that a major shift was required. Nonetheless, at the Blackberry 10 launch event in January this year, Heins credited Balsillie for the strong relationships that Blackberry currently has with the world’s mobile operators.