What Causes the Favorite-Longshot Bias? Further Evidence from Tennis

In sports betting markets, bets on favorites tend to have a higher expected value than bets on longshots. This article uses a data set of almost 45,000 professional single tennis matches to show that the favorite-longshot bias is much stronger in matches between lower-ranked players, in later-round matches, and in high-profile tournaments. These results cannot be solely explained by bettors being locally risk-loving or overestimating chances of longshots, but are consistent with bookmakers protecting themselves against both better informed insiders and the general public exploiting new information