Let's assume there is a professional gambler named "Bob". He has designed his own betting strategy by improving a strategy he purchased online, he has also looked into trading where he is more than successful and at the same time he has studied Texas Hold'em Poker so well that he manages to show significant profits over the past months. The problem is Bob has only one life, how can he make most of it?

Examining his strategy he uses to bet on football, tennis and other sports, his ROI (Return on Investment) is about 10%. That means that for every euro, pound or dollar he bets, he makes 0.10 of it in the long run. During the past years his betting activity averages at around 1,000 bets per year and Bob being a wealthy man, he usually bets 1,000 €/₤/$ per game. So, Bob expects to make 100,000 during each year out of sports betting.

On the other hand, he has performed well in trading the horse racing, tennis and snooker markets. His collected data shows a ROI of 0.3% and given he trades large volumes such a small ROI can mean big profits. His yearly turnover reaches almost 60,000,000 €/₤/$ which combined with the ROI results to 180,000 profit during each year out of sports trading.

Finally, poker has lately taken over the entire world and Bob couldn't stand not being part of this hype. He has devoted hundreds of hours playing and studying the game and by improving his game, he has managed to show a steady profit of 3BB (big bets, twice the big blind) per 100 hands at medium stakes of No Limit Poker. He knows good players win about 5BB or so but he is still satisfied by his performance. Playing 6 tables simultaneously for 7 hours on a daily basis, he sees over 4,000 hands per day. Considering his win rate at 3BB/100, his profit averages at 120BB/day. Most of the time Bob is found to play at 200NL up to 600NL tables. When he plays 200NL (1/2 small blind/big blind), his win rate is 480 €/₤/$ (=120BB * (2 * 2)). At 400NL the win rate reaches almost 1,000 and at 600NL he is making 1,500 considering his 3BB/100 rate. Of course, he doesn't play each day. 5 days per week is his common poker occupation which results to 260 days per year. If he is to play always at 400NL, Bob expects to make almost 260,000 each year out of poker.

In conclusion, is poker indeed the most profitable gambling activity? Yes and no. Remember we are talking about an imaginary person and we have made quite a few assumptions (and we have not even taken into account the currency conversion if you happen to bet, trade or play poker in different currencies). Maybe a professional gambler can show 20% ROI in sports betting, probably he can be better in sports trading where he manages a 0.8% ROI or trades even bigger amounts of money, and possibly he is such a great poker player that he can win at 2,000NL tables at 5BB/100 rate. It all depends on the individual's performance. Collect your own betting/trading/poker data, study your own performance and you'll see how you can make most of your time.

Best of luck!