Expected value Statistic Value Reference Average ROI for sports bettors 1-3% https://www.thespread.com/general-sports-articles/080618-how-to-determine-the-roi-of-a-sports-betting-system/amp Top 10% of sports bettors’ ROI ~30% https://www.gamblingsites.com/sports-betting/introduction/profitability/ Highest recorded yearly ROI by a sports bettor