zlacker

Many sportsbooks actually do not run that way. The name "sportsbook" implies that they do, but that is an older style of betting that has fallen out of favor. Modern sports books usually use fixed odds set by an oddsmaker (in modern times, algorithms set by the oddsmaker), but those odds are allowed to float with the probability of the outcome changing. I believe they take supply and demand into account, but you actually are betting against the house. That prevents the kind of trading against the crowd that would be normally viable.

The Hong Kong horse race track was a famous example of market-priced bets where the book was run the way you said and the crowd was exploitable in the way you are suggesting. It was one of the last books to work that way.

>>pclmul+(OP)
I can see the misunderstanding, but I was not actually describing parimutuel betting (horseracing). In parimutuel betting the odds continue to change up until the race even once you've placed your bet ensuring that the payout is always the total amount wagered less a fee kept by the house.

Sportsbooks will open lines intelligently, but they absolutely do move the line in response to market forces in an attempt to balance money on both sides, because when the money is balanced, they are guaranteed profit.

It's true that when you make a sports wager, the house is paying you out of their wallet. It's also true that they employ a lot of energy and expertise in order to open the betting at accurate odds. However, no corporate, end user facing sportsbook is themselves fading action on one side of the match intentionally. They aggressively try to balance money on both sides so they can guarantee a profit.