Line movement refers to changes in odds or point spreads from the time a line opens to when it closes at game time. Lines move due to sharp betting action, injury news, weather changes, roster announcements, or significant public betting volume. Tracking line movement is one of the most valuable skills a bettor can develop because it reveals where informed money is going. Understanding whether a move is driven by sharp bettors with a proven track record or by casual public money can fundamentally change how you approach a game.
Example
The Bills open at -3 and move to -4.5 by kickoff. This 1.5-point move suggests sharp money on the Bills, meaning professional bettors wagered enough to force the sportsbook to adjust. Sharps bet them early at -3, and the book moved the line to reduce its exposure. Conversely, if the line moved because 80% of public bets are on the Bills but the line only moved half a point, that might indicate the book is comfortable with its position, or sharp money is actually on the other side. This distinction is critical for making informed wagers.
Common Questions
What causes lines to move?
What causes lines to move?
Lines move for several reasons, and understanding each is important. Sharp money from professional bettors with winning track records is the most significant driver since books respect these wagers and adjust quickly. Injury reports and lineup changes force recalculations of team strength. Weather updates, particularly in outdoor sports like NFL and MLB, can shift totals and spreads. Large public betting volume on one side also triggers movement as books try to balance their liability. Books may also move lines preemptively in anticipation of news or to align with other sportsbooks' numbers.
Should I bet with or against line movement?
Should I bet with or against line movement?
It depends on what's causing the movement. If the line moved because of sharp money, betting with the move early, before it shifts further, is generally smart because you're aligning with informed bettors. If the movement is driven by public money and casual bettors piling on a popular side, fading the move and taking the other side can be profitable since the public tends to overvalue favorites and overs. The critical step is identifying why the line moved. Tools that track betting percentages versus line direction can help you distinguish sharp moves from public ones.
What is reverse line movement?
What is reverse line movement?
Reverse line movement occurs when the line moves in the opposite direction of where the majority of bets are placed. For example, if 75% of bets are on the Bills -3, but the line drops to Bills -2.5, that's reverse line movement. It strongly suggests that sharp money is on the other side, and the book values that sharp action more than the volume of public bets. Reverse line movement is one of the most reliable indicators of where professional bettors stand on a game, and many successful handicappers use it as a core part of their analysis.