Line Movement

Definition:

In sports betting, line movement refers to changes in the odds or point spread after the sportsbook first releases them. Lines shift based on factors like betting volume, injuries, weather, or sharp money (professional bettors).

They serve two main purposes:

1. Adjust odds to balance action on both sides and protect the sportsbook from lopsided risk.

2. Reflect new information (injuries, weather, roster changes) or strong betting trends.

Real-World Example

NFL Game: Philadelphia Eagles vs. Dallas Cowboys

• Opening line: Eagles –2.5 (–110).

• After heavy public betting on the Eagles, the line moves to Eagles –3.5 (–110).

  • A bettor who took the Eagles early at –2.5 gets a better number.

  • Late bettors must now cover an extra point, which could be the difference between a win and a push/loss.