The second-largest stakeholder in BlackBerry now holds 54.9 million shares, or about 10.4 per cent of the company's outstanding equity, according to figures filed with the Securities and Exchange Commission.
That's an increase from a 6.5-per cent stake as of Dec. 31, 2013.
BlackBerry has been making significant changes to its operations under the leadership of John Chen, who previously helped rescue technology firm Sybase.
In its most recent financial results, the company posted a first-quarter loss of US$423 million or 80 cents per share, which on an adjusted basis was a smaller loss than analysts expected.
Chen aims to make Blackberry break even by the end of next February.