Originally <a href='http://www.sportsbookreview.com/forum/showthread.php?p=6457299'>posted</a> on 09/19/2010:
Return on bankroll does not equal ROI. Say you have a $100k bankroll and make 1000 $1k bets in a month and have an ROI of 2%. You've just made $20k and have a 2% ROI but you have a 20% return on bankroll.