The general rule regarding parlays is: DON'T.
Parlays generally carry a higher house edge than straight bets, therefore you give the book a more impressive advantage over you when you play them. That, by itself, is reason enough to suppress the misplaced feelings of greed coupled with fear that often lead to betting parlays. People think they're risking less with parlays, however they aren't. They believe they can win more with parlays, but they cannot. The bigger win with parlays is far outweighed by the bigger probability of losing. Parlay bettors are in fact risking more, with less probability of collecting.
A parlay is not a single bet. It really is two bets -- a one-unit bet on one team and a two-unit bet on the other. Which team gets the two-unit bet? In point-spread betting at constant money odds, if both teams win or both teams lose it doesn't matter which team gets the double bet. When one team wins and one team loses, however, the double bet is presumed to have been on the loser. How smart is that for the bettor? Go ahead, create a parlay. We'll wait until both games are over, and in case there is a split we'll put the double bet on the loser. If your bookmaker sold you a parlay with that line, just how many of you'll still make the bet?
A parlay is also bad money management. In a parlay you either bet double on the second team, or nothing on that same team, depending upon whether the first game won or lost. That adds an element of luck to your betting that doesn't should be there. The skilled handicapper is definitely seeking to make smart investments. He tries to remove the result of luck to the greatest extent possible in order to make his results as predictable as possible.
Much like every rule, however, there are exceptions. The exception to the rule regarding parlays occurs once the two bets are co-dependent.
I knew one bookmaker who was taken for thousands because he didn't understand the co-dependency of certain bets. He allowed a player to consistently parlay the initial half with the overall game. The player parlayed totals by combining the over in the first half with the over in the overall game, and the under in the initial half with under in the overall game. Both parlays were manufactured in the same game. Every time the player won he would win 2.6 times his bet. Betting $100 on each parlay, if one of these won, the player would win $260 and lose $100 on the other parlay for a net win of $160. He could never win both parlays. If he lost both parlays he'd lose $200.
At first glance, this were a great opportunity for the book. The normal coin-flip probability of winning one parlay out of the two are 50-50. So far as the bookie was concerned the bettor ought to be winning $160 half enough time, and losing $200 half enough time. The bettor, however, making $500 parlays, was ahead a lot more than $20,000 after six months, and the book begun to look at what the bettor was doing more carefully.
The issue for the bookmaker was that both halves of each parlay were co-dependent. At the end of the first half, the bettor was hardly ever in a 50-50 situation.
Take the Thursday night game between Utah and Air Force. The game total was 53 and the first half total was 27. By the end of the first half, the score was 31-21, for a complete of 52 first-half points. The first half of one of many parlays, the "over" in the initial half was a winner. For the parlay probability to be correct, there should now be a 50-50 probability of winning the "over" for the overall game. Obviously the chances of winning the "over" in the overall game were not 50-50 but much better than 99% and only the "over." 789bet had a need to win the first half of the parlay to be virtually assured that he would collect 2.6 times his money instead of just $10 for $11.
Before you rush out to use this, be aware that most off-shore books are much too smart to enable you to parlay first half to game. Should they do permit you to do this, start fretting about collecting because that book will soon be taken to the cleaners.
There are, however, some less obvious co-dependent parlays that may still be made at many books. One kind of co-dependent parlay is the parlay of the side and total in exactly the same game.
Any game where the total is less than double the spread can provide you an edge in parlaying side to total in the same game. We've already discussed, in a prior article, how to use these anomalous side and total combinations to hedge one another and boost your win with hardly any increase in risk. This type of bet, however, required that you have an impression privately or the total. Parlaying is another solution to increase your potential win on these games, or to create a potential win when you have no opinion.
There are two games this Saturday that qualify. They are Virigina -25 over Duke with a complete of 48 �, and Kansas St. -24 � vs. North Texas with a total 46 �).
In the Virginia game, if you believe that Virginia will cover the 25 points, then they must hold Duke to no more than 11 points or the overall game will go over the full total. The more likely it becomes during the game that Virginia will cover 25 points, the much more likely it becomes that the game will go over 48 �. The wider Virginia's winning margin, the more likely the game will go over. If you want Virginia to cover the spread, and you believe that Duke will not be shut out, then your possibility of winning a parlay on Virginia and the over are higher than the standard 25%. Likewise, if the scoring stays low, it really is not as likely that Virginia will cover the 25 points. Subsequently, the probability a parlay of the under with the underdog will win is greater than the normal 25%.
Should you have no opinion on the overall game, you can parlay the favorite with the "over" and the underdog with the "under" and collect sufficiently often to exceed the losses when both parlays lose. In the only real other game meeting the qualifications this week -- Friday's game between California -30 against New Mexico State with a complete of 58 -- the under has already won with the underdog for an absolute two-parlay spread.
The closer the posted total would be to the spread on the side, the better win-rate will be on the parlay "spread" bet. The co-dependency in side to total parlays isn't as strong as parlaying first half and game totals (if it were, most books would not allow such bets), but there is a sufficient co-dependency in the games with low totals and high spreads to help make the strategy profitable long-term.
Not all bookmakers will help you to parlay the medial side to the full total in the same game, because a growing number of are realizing that these bets are sometimes co-dependent. But, enough books still do allow such bets so you might consider including such bets in your professional betting arsenal.
If your bookmaker provides "if/reverse" bets, you can replace the parlay bet with an "if/reverse" bet and achieve greater success.