FanDuel primarily makes money from the sportsbook off of losing bets. However, it also uses vigorish. FanDuel factors vigorish into the odds and it works like a commission on wagers. As an example, if the odds on a wager are -110 and you receive $100 for a $110 winning bet, the $10 that FanDuel keeps is the vigorish. The exact amount that FanDuel takes varies by bet type.