The general rule regarding parlays is: DON'T.
Parlays generally carry a higher house edge than straight bets, which means you give the book a bigger 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 are risking less with parlays, however they aren't. They believe they are able to win more with parlays, but they cannot. The higher win with parlays is far outweighed by the higher probability of losing. Parlay bettors are actually risking more, with less probability of collecting.
A parlay is not a single bet. It really is two bets -- a one-unit bet using 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 something 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, just how many of you'll still make the bet?
A parlay can be 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 some luck to your betting that doesn't ought to be there. The skilled handicapper is always seeking to make smart investments. He tries to get rid of the result of luck to the best extent possible to make his results as predictable as you possibly can.
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 taken for tens of thousands because he didn't understand the co-dependency of certain bets. He allowed a new player to consistently parlay the first half with the game. The ball player parlayed totals by combining the over in the initial half with the over in the overall game, and the under in the first half with under in the game. Both parlays were manufactured in the same game. Each and every 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 another 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 chance for the book. The normal coin-flip odds of winning one parlay from the two are 50-50. As far as the bookie was concerned the bettor ought to be winning $160 half the 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 begun to look at what the bettor was doing more carefully.
The problem for the bookmaker was that the two halves of every parlay were co-dependent. At the end of the first 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 initial half total was 27. At the end of the first half, the score was 31-21, for a complete of 52 first-half points. The initial half of among the parlays, the "over" in the first half was a winner. For the parlay probability to be correct, there should now be considered a 50-50 possibility of winning the "over" for the game. Obviously the odds of winning the "over" in the overall game were not 50-50 but better than 99% in favor of the "over." bj88 had a need to win the first half of the parlay to be virtually assured he would collect 2.6 times his money instead of just $10 for $11.
Before you rush out to use this, remember that most off-shore books are much too smart to let you parlay first half to game. If they do let you do this, start worrying about collecting because that book will soon be taken to the cleaners.
You can find, however, some less obvious co-dependent parlays that may be made at many books. One kind of co-dependent parlay may be the parlay of the side and total in exactly the same game.
Any game in which 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 exactly to use these anomalous side and total combinations to hedge each other and boost your win with very little increase in risk. Such a bet, however, required that you have an opinion privately or the total. Parlaying is another method to increase your potential win on these games, or even to develop a potential win assuming you 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 covers the 25 points, they must hold Duke to no more than 11 points or the game will go over the total. The more likely it becomes through the game that Virginia covers 25 points, the more likely it becomes that the game will go over 48 �. The wider Virginia's winning margin, the much more likely the game will go over. If you want 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 is less likely that Virginia will cover the 25 points. Because of this, the probability that a parlay of the under with the underdog will win is higher than the normal 25%.
Assuming you have no opinion on the overall game, you can parlay the favourite with the "over" and the underdog with the "under" and collect sufficiently often to exceed the losses when both parlays lose. In the only 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 privately, 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 wouldn't normally allow such bets), but there is a sufficient co-dependency in the games with low totals and high spreads to make the strategy profitable long-term.
Not all bookmakers will help you to parlay the side to the total in the same game, because a growing number of are realizing that these bets are occasionally 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.