Here are the most profitable sports when betting against the spread: College Football (97.83% OPT. ROI SCORE) NFL (90.2% OPT. ROI SCORE) College Basketball (36.91% OPT. ROI SCORE) NHL (12.39% OPT. ROI SCORE) NBA (10.33% OPT. ROI SCORE) MLB (8.81% OPT. ROI SCORE) Oct 3, 2019