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 combined 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, however they cannot. The bigger win with parlays is far outweighed by the bigger possibility of losing. Parlay bettors are in fact risking more, with less probability of collecting.
A parlay is not an individual bet. It really is two bets -- a one-unit bet on 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 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, make 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, 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 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 you possibly can.
As with 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 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 first 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 first half with under in the game. Both parlays were made in the same game. Every time the player won he'd win 2.6 times his bet. Betting $100 on each parlay, if one of these 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 would lose $200.
At first glance, this were a great opportunity for the book. The normal coin-flip odds of winning one parlay out of your two are 50-50. So far as the bookie was concerned the bettor should 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 initial half, the bettor was hardly ever in a 50-50 situation.
Take bsports world between Utah and Air Force. The overall 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 total of 52 first-half points. The initial half of among the parlays, the "over" in the first half was successful. For the parlay probability to be correct, there should now be a 50-50 probability of winning the "over" for the game. Obviously the odds of winning the "over" in the game were not 50-50 but much better than 99% in favor of the "over." The ball player only had a need to win the first 1 / 2 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, be aware that most off-shore books are far too smart to allow you to parlay first half to game. Should they do let you do this, start fretting about collecting because that book will soon be taken up to the cleaners.
You can find, however, some less obvious co-dependent parlays that may still be made at many books. One type 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 significantly less than double the spread can give 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 increase your win with very little increase in risk. Such a bet, however, needed that you have an impression on the side or the full total. Parlaying is another method to increase your potential win on these games, or to create a potential win for those who have no opinion.
There are two games this Saturday that qualify. They're Virigina -25 over Duke with a total of 48 �, and Kansas St. -24 � vs. North Texas with a total 46 �).
In the Virginia game, if you believe that Virginia covers the 25 points, then they must hold Duke to only 11 points or the overall game will go over the total. The much more likely it becomes during 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 more likely the game will go over. If you want Virginia to cover the spread, and you also believe that Duke will not be shut out, in that case your possibility of winning a parlay on Virginia and the over are greater than the standard 25%. Likewise, if the scoring stays low, it really is not as likely that Virginia will cover the 25 points. Because of this, the probability a parlay of the under with the underdog will win is greater than the normal 25%.
In case 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 other game meeting the qualifications this week -- Friday's game between California -30 against New Mexico State with a total of 58 -- the under has already won with the underdog for a winning two-parlay spread.
The closer the posted total is to the spread privately, the better win-rate will undoubtedly 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 wouldn't normally allow such bets), but you will find 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 allow you to parlay the side to the total in the same game, because a lot more are realizing these bets are occasionally co-dependent. But, enough books still do allow such bets for you to consider including such bets in your professional betting arsenal.
If your bookmaker provides "if/reverse" bets, it is possible to replace the parlay bet with an "if/reverse" bet and achieve greater success.