In the United States sports betting is only legal in the state of Nevada but more wagering is done on sporting events than any other form of gambling. Offshore sports sites, illegal bookmaking operations, office pools and bets amongst friends and sports fans make it the number one gambling activity.
The casino Sports books make their money on sports bets by collecting a commission on losing bets. This is called the Vigorish or Vig for short. The most common odds are 11 to 10. This means that if you want to win $100 you are risking $110. For example you place a bet on the Giants at the casino sports book and pay $110. If the Giants win you collect $210 when you cash your winning ticket. If you lose your bet you lose the $110.
Ideally the Sports book would like to have the same amount of money wagered on the two teams playing. If the Giants are playing the Colts and they have one player betting on the Giants and one player betting on the Colts they would pay the winner $100 but collect $110 for the loser. This gives them a $10 profit so they really don’t care who wins as long as they have an equal amount bet on each team. To accomplish this they assign a line or spread to make the contest equally attractive for both sides.
