A sportsbook is a gambling establishment that accepts wagers on a variety of sporting events. These wagers may be on the outcome of a specific game, on the total score in a matchup, or on individual players and teams. Generally, the sportsbooks will also offer what are called “props” (or proposition bets), which are wagers on things like who will win a specific play, or on whether a player will score a touchdown in a given game.
Sportsbooks make their money the same way that any bookmaker makes money: They set the odds for each bet such that it will guarantee them a return in the long run. This is called vigorish, or juice, and it helps the sportsbooks offset their overhead costs, including paying out winning wagers.
The betting market for a particular sporting event begins to take shape almost two weeks in advance of kickoff. Each week, a handful of sportsbooks will release what are known as look-ahead lines, or 12-day numbers. These initial odds are based on the opinions of a few sportsbook managers, and they don’t have much thought put into them. The opening odds are often a thousand bucks or two, which is a significant amount of money for the average bettor, but less than a professional would risk on a single NFL game.
As the betting market evolves, the opening odds will start to change. The changing odds will be influenced by the public’s money, or handle, as well as steam, or momentum, which is when one side of a wager has growing action. This will affect the closing line/odds, which are the final odds posted before a game begins.