Stale Line

A stale line is a set of odds that has not yet been adjusted to reflect new, relevant information that would normally cause the line to move. When something material changes — a star player is ruled out, a starting pitcher is scratched, severe weather rolls in, or a key piece of news breaks — sportsbooks need time to react and update their prices. During that window, the old odds remain posted and no longer represent the true probability of the outcome. Bettors who spot the new information before the book adjusts can wager at a price that offers more value than the market should be providing.

Stale lines occur most frequently at smaller or slower-moving sportsbooks that do not have the same real-time data feeds and automated trading systems as the major market makers. They are also more common in niche markets, lower-tier leagues, and prop bets where sportsbooks dedicate fewer resources to monitoring and updating lines. In mainstream markets like the NFL or NBA, the window of staleness tends to be very short — often just seconds or minutes — because automated systems and sharp bettors quickly force the price to its new equilibrium. For in-play (live) betting markets, stale lines can appear even more briefly due to the rapid pace of events during a game.

Example

A sportsbook has an NBA game line with the Boston Celtics at -6.5 (-110). Thirty minutes before tip-off, a credible reporter tweets that the Celtics’ starting point guard will miss the game with a calf injury. One major sportsbook immediately moves its line to Celtics -4.5, but a smaller book still shows Celtics -6.5 because it has not yet processed the news. A bettor who sees the injury report quickly places a wager on the opposing team at +6.5 at the smaller book, capturing nearly two full points of value compared to the updated market price.

Key Points

• Speed is essential: The window to exploit a stale line is typically very short. By the time the information is widely circulated on social media and news outlets, most books will have already adjusted their odds.
• Multiple accounts help: Having accounts at several sportsbooks increases the chances of finding a book that is slow to update. Market-making books adjust fastest, while regional or newer books tend to lag behind.
• Live betting is especially prone: In-play odds must update continuously as the game unfolds. Delays in the data feed or the trading algorithm can produce stale live lines, which is why many sportsbooks impose brief delays on live bet acceptance.
• Sportsbooks protect themselves: Books that notice accounts consistently betting into stale lines may limit or restrict those bettors. Winning on stale odds is not illegal, but it is the type of activity that sportsbooks monitor closely.