As bets are taken on a matchup throughout the week, sportsbooks often reduce the juice on one team so the line is, say, -105, which gives bettors the chance to win $100 by risking less money. Sportsbooks might also increase the juice if more action is going to a particular team, which forces bettors to risk more money to win $100 on the point spread.
Sportsbooks raise or lower the juice — or increase or decrease the point spread — because their ultimate goal is to keep action on both sides balanced.
Why the point spread changes
When a point spread is perceived by bettors as accurate upon initial release, bettors will put equal action on both teams.
This is rarely the case, so sportsbooks often move the line to balance unequal early action.
Let's say the Memphis Grizzlies open as an
8.5-point underdog against the Utah Jazz, but a large number of bettors think Memphis will beat that spread.
If more money goes to Memphis early on, the sportsbook might adjust the line, either by raising the juice to -120 or greater, or by shifting the point spread to eight points.
As the spread becomes smaller, bettors eventually will find Utah a more attractive bet and begin placing more money on the Jazz, which balances out the action.
Sharp money, or money wagered by professional bettors, will often shift the point spread, too.