Research on sports betting often attempts to identify biased evaluation by bookmakers, opening opportunities for pro table strategies to bettors. Previous studies have provided evidence for the existence of such ine ciencies. Since most studies cover only a few seasons, the question of whether market ine ciencies per- sist over time remains unanswered. We analyse the big ve leagues in European association football for fourteen seasons to detect the occurrence and duration of market ine ciencies. While our results suggest that most biases do not persist for a long time, we still uncover pro table betting strategies throughout the full observation period.