Beating the bookies with their own numbers - and how the online sports betting market is rigged 1,2* 3* 4* Lisandro Kaunitz , Shenjun Zhong and Javier Kreiner 1- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan. 2- Progress Technologies Inc., Tokyo, Japan. 3- Monash Biomedical Imaging Center, Monash University, Melbourne, Australia. 4- Data Science department, CargoX, Sao Paulo, Brazil Corresponding authors: Lisandro Kaunitz / Javier Kreiner E-mail:
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[email protected] Abstract The online sports gambling industry employs teams of data analysts to build forecast models that turn the odds at sports games in their favour. While several betting strategies have been proposed to beat bookmakers, from expert prediction models and arbitrage strategies to odds bias exploitation, their returns have been inconsistent and it remains to be shown that a betting strategy can outperform the online sports betting market. We designed a strategy to beat football bookmakers with their own numbers. Instead of building a forecasting model to compete with bookmakers predictions, we exploited the probability information implicit in the odds publicly available in the marketplace to find bets with mispriced odds. Our strategy proved profitable