[Jurollo]

Realize that every tournament has a fee as well. Take for instance this week's $50K on empire. 441 entrants = $44,100, seemingly a large $5,900 overlay but then take the $10 in entry fees for each player and you get $48,510... only a total $1490 overlay which is NOTHING for these sites, especially in return for getting players to keep $110 or more in their accounts as this will generally mean they'll play elsewhere on your site as well. While they lose money on the tourney itself remember they can't make money in other ways without having customers and these guarantees get customers there.
~Justin