The private person with the most BTC is probably
ArtForzEdit: Forgot that guy below. Yes, if he wasn't entirely stupid it's pirate.
But I can really imagine that he lost most of the coins himself by trying to manipulate the market and has "only" something around a 100.000 left. Surprisingly Ponzi operators often convince themselves that their plan actually works and are caught by surprise when their ponzi collapses.