So, when Don Money asked me if Mark Cuban's hedge fund for sports gambling would be something I would invest in, I needed to post my "if I only lived in Vegas" musings to answer fully.
Yes, DM, I would, but only if Mr. Cuban met with me for a few minutes first to discuss what I believe is a foolproof plan for sports gambling if you had the time and money.
Now, perhaps you may have heard of the doubling system in Blackjack. Essentially, that is a betting system that is "in theory" foolproof. What it requires is that you start off with a bet, let's say $1. If you win, you put that $1 profit away, and you bet $1 again. Every time you lose, however, you double the bet--i.e., if you lose, you bet $2 next, then $4, then $8, etc. When you finally win a hand, you will have recouped your losses and actually won $1. You put that $1 profit away and start over.
The casinos know this, which is the reason that blackjack tables have maximum bets (you thought it was because they didn't want you to lose more than $5000 at a time?). The maximum bet rule stops the doubling system because while you will definitely win a hand eventually, you may actually lose the 11 or so hands in a row it will take you to be more than $5000 down at a $5-$10 minimum table. If there was no such maximum, and you had a serious bankroll, you could make blackjack a career and never lose. With the maximum limit, you can lose and lose a lot.
Sports betting in Vegas is subject to no such maximums of which I know. Therefore, the doubling system should in theory be foolproof. The beauty of it is also that it doesn't matter who you bet on, what sport, or what knowledge you have as long as you follow two important rules: 1) only bet on the 50-50 spread and over/under lines (as opposed to odds, parlays, money lines, etc.) and 2) do not bet on multiple things at once.
This works especially well during baseball season when there are multiple game starts throughout the day. Assuming you start on the first day of the season, figure about 190 days of baseball and about two-three segments of games (2pm eastern, 8pm eastern, 11pm eastern) each day, so you'd be making about 500 bets a season. Let's assume $100 per bet, each win gets you a profit of $100 (I'm ignoring the percentages that the casino takes--you can adjust the bets accordingly to take this into account ($110 to win $100 the first time, $231 to win $210 the second time, etc.)). With 50-50 odds, you should win approximately 250 of the bets leading to a profit of $25,000.
Anyway, I don't live in Vegas and I don't have Mark Cuban's bankroll. But, Mr. Cuban, if you use this strategy and add to your billions, I expect a small cut :-)