Some, possibly all, are owned by private investors (non-insiders) who took place in private placements along the way.  I remember Canadian and other accredited investors taking part in two recent placements (warrant strike prices of around $3.00 and 4.00 per share) and they were likely involved in earlier ones (which would have generated warrants with lower strike prices).  The news release indicates that there are 16+ million of them and they may well show up in the market.

Jupe