The gain came despite the company reporting a net loss of $693,000 after tax, and revenue of just $436,000.
Multiple directors and senior management had sold shares during the latest rally, and one director sold 5,861,000 shares - more than 1 per cent of the microcap company, broking house Jarden noted.
Some market commentators suggested that the stock has been driven purely by casual investors enticed by its gains, given its consistent appearance on the NZX top gainers' board and commentary on the Sharesies share trading chat forum.
After coming out of a trading halt, the stock last traded at 4c, down 5.1c or 56 per cent from Thursday's close.
The NZX sent two inquiries to BGI - one on June 22 and the other on Wednesday this week - about the big moves in its share price.
BGI chairman Sean Joyce, in both instances, said the company's directors were not aware of any material information that should be released to the markets.