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 once you play them. That, by itself, is reason enough to suppress the misplaced feelings of greed combined with fear that often lead to betting parlays. People think they're risking less with parlays, but they aren't. They believe they can win more with parlays, however they cannot. The bigger win with parlays is far outweighed by the higher possibility of losing. Parlay bettors are actually risking more, with less possibility of collecting.
A parlay is not an individual bet. It is two bets -- a one-unit bet using one team and a two-unit bet on another. 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? Just do it, create a parlay. We'll wait until both games are over, and in case of a split we'll put the double bet on the loser. If your bookmaker sold you a parlay with that line, how many of you would still make the bet?
A parlay is also bad money management. In a parlay you either bet double on the next team, or nothing on that same team, dependant on whether the first game won or lost. That adds some luck to your betting it doesn't should be there. The skilled handicapper is always seeking to make smart investments. He tries to remove the result of luck to the best extent possible to make his results as predictable as possible.
As with every rule, however, you can find exceptions. The exception to the rule regarding parlays occurs when the two bets are co-dependent.
I knew one bookmaker who was simply taken for tens of 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 initial half with the over in the game, and the under in the first half with under in the game. Both parlays were made in the same game. Each time the player won he'd win 2.6 times his bet. Betting $100 on each parlay, if one of them won, the ball 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.
Initially, this were a great opportunity for the book. The normal coin-flip probability of winning one parlay out from 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 more than $20,000 after six months, and the book started to look at what the bettor was doing more carefully.
The problem for the bookmaker was that both halves of every parlay were co-dependent. By Hi88 of the initial half, the bettor was almost never in a 50-50 situation.
Take the Thursday night game between Utah and Air Force. The overall game total was 53 and the first half total was 27. At the end of the first half, the score was 31-21, for a total of 52 first-half points. The first half of among the parlays, the "over" in the first half was successful. For the parlay probability to be correct, there should now be considered a 50-50 possibility of winning the "over" for the overall game. Obviously the odds of winning the "over" in the game were not 50-50 but better than 99% and only the "over." The player only had a need to win the first half of the parlay to be virtually assured that he would collect 2.6 times his money rather than just $10 for $11.
Before you rush out to use this, remember that most off-shore books are much too smart to allow you to parlay first half to game. Should they do let you do this, start worrying about collecting because that book will soon be taken up to the cleaners.
You can find, however, some less obvious co-dependent parlays that can be made at many books. One kind of co-dependent parlay is the parlay of the medial 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 exactly the same game. We've already discussed, in a prior article, how exactly to use these anomalous side and total combinations to hedge one another and boost your win with hardly any increase in risk. Such a bet, however, needed that you have an opinion privately or the full total. Parlaying is another solution to increase your potential win on these games, or to develop a potential win for those who have no opinion.
You can find 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 complete 46 �).
In the Virginia game, if you believe that Virginia will cover the 25 points, they must hold Duke to no more than 11 points or the overall game will go over the total. The much more likely it becomes through the game that Virginia will cover 25 points, the much more likely it becomes that the overall game will review 48 �. The wider Virginia's winning margin, the more likely the game will go over. If you like Virginia to cover the spread, and you believe that Duke will never be shut out, then your probability of winning a parlay on Virginia and the over are higher than the normal 25%. Likewise, if the scoring stays low, it really is less likely that Virginia will cover the 25 points. Because of this, the probability a parlay of the under with the underdog will win is higher than the normal 25%.
Should you have no opinion on the 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 is 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 is not as strong as parlaying first half and game totals (if it were, most books would not allow such bets), but there exists 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 total in exactly the same game, because increasingly more are realizing these bets are occasionally co-dependent. But, enough books still do allow such bets that you should consider including such bets in your professional betting arsenal.
If your bookmaker provides "if/reverse" bets, it is possible to replace the parlay bet having an "if/reverse" bet and achieve greater success.