The regulatory filing didn't say when during 2012 he sold his shares in the in the Waterloo, Ont.-based company or for how much.
At the end of 2011, while he was still co-CEO of what was then called Research In Motion, Balsillie held 26.8 million shares, or 5.1 per cent of the company. At the time, BlackBerry stock traded at just under $15 on the TSX, meaning his shares would have been worth $397 million.
In 2012, BlackBerry stock, which previously traded under the ticker symbol RIM, traded as high as $18.23 a share and as low as $6.10.
In January last year, Balsillie and fellow co-CEO Mike Lazaridis stepped down to allow Thorsten Heins to take the reins as CEO, while they stayed on the company's board of directors.
But in late March, Balsillie resigned from the board, reportedly over a long-standing disagreement between Balsillie and Heins over the company's long-term direction.
Under the leadership of Balsillie and Lazaridis, RIM's BlackBerry became the world's most popular smartphone before losing ground to competitors like Apple's iPhone and phones powered by Google's Android operating system.
BlackBerry shares surged $1.05, or 7.5 per cent, to close at $15.05 on the TSX Thursday.