Closing Line
Definition
The closing line is the final set of odds offered by a bookmaker just before an event begins. It represents the most accurate market price because it incorporates all available information and betting action. Beating the closing line consistently is the hallmark of a skilled bettor.
Example
An NFL game opens with the Patriots at -3.5. By game time, the line has settled at -4.5. The closing line is -4.5. If you bet Patriots -3.5, you got better value than the closing line.
Related Terms
Vig / Juice
MarketVig (short for vigorish) or juice is the commission the bookmaker charges on each bet. It is built into the odds so that the sum of implied probabilities exceeds 100%. The vig is how sportsbooks guarantee a profit regardless of the outcome.
Overround
MarketOverround (also called margin or book percentage) is the total implied probability across all outcomes in a market. The amount by which it exceeds 100% represents the bookmaker's built-in advantage. Lower overround means fairer odds for the bettor.
RTP (Return to Player)
MarketRTP is the inverse of the overround, expressed as the percentage of total stakes that is returned to bettors as winnings over time. Higher RTP means lower bookmaker margin and better value for bettors.
Steam Move
MarketA steam move is a sudden, sharp line movement caused by heavy action from professional bettors (sharps) across multiple bookmakers simultaneously. Steam moves signal strong opinions backed by significant money and can indicate genuine value before the broader market adjusts.
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