In sports betting, a sportsbook is the place where bettors can place wagers on various sporting events. The sportsbook’s odds are based on the likelihood of an event occurring, and they can be displayed in a variety of ways. They can be written as a percentage of the total amount of money wagered on one side of the bet or as an implied probability of winning. The latter can be helpful for bettors as it makes the odds more transparent.

A sportsbook’s odds are set by a head oddsmaker, who uses sources like computer algorithms and power rankings to set prices. The head oddsmaker may also use promotions to manipulate the line. For example, if a team is expected to win a game, the sportsbook will move the line to encourage bettors to take the opposite side. This is to balance out the book’s bottom line.

Many sportsbooks offer parlays, which allow bettors to combine different bet types or outcomes on a single ticket. Getting all of the selections correct in a parlay is challenging, but the payoff can be enormous. For example, a bet on the under/over in a basketball game can yield a huge payout. However, the sportsbook’s hold is much higher on these bets than on single-event bets.