What is reverse line movement in sports betting?

The idea rests on a simple expectation. If most wagers are on a favorite, an operator that only balanced its book would be expected to raise the favorite's spread or price, not lower it. When the number goes the other way, observers conclude that fewer but larger or more respected wagers are on the underdog and outweigh the crowd. The pattern is usually described with two figures, the share of tickets and the share of money, which can point in different directions.

What can be known is limited. The ticket and money percentages that circulate come from data services that sample some operators, and each operator keeps its own book private. What cannot be known from outside is who placed the wagers, how large they were, or whether the move came from them at all. Injury news, a change in the starting lineup, an operator following a competitor and exposure on related markets can all produce the same move.

Treat it as a prompt to investigate, not a conclusion. Check whether several operators moved or only one, whether the move followed a news item, and whether the number kept going or drifted back. A move that survives those checks is more interesting than a one-point wobble at a single operator, but it still tells you where some money may have gone, not whether that side is a good price.