The general rule regarding parlays is: DON'T.
Parlays generally carry an increased house edge than straight bets, therefore you give the book a more impressive advantage over you when you play them. That, alone, 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 can 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 an individual bet. It 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 no 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, 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 next 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 should be there. The skilled handicapper is always seeking to make smart investments. He tries to get rid of the effect of luck to the greatest extent possible in order to make his results as predictable as you possibly can.
Much like 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 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 ball player parlayed totals by combining the over in the first 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. Every time the player won he would 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 of the two are 50-50. As far as the bookie was concerned the bettor should 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 6 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 each parlay were co-dependent. By the end of the initial half, the bettor was hardly ever in a 50-50 situation.
Take https://mb66.bz/ between Utah and Air Force. The overall game total was 53 and the first half total was 27. By the end of the initial half, the score was 31-21, for a total of 52 first-half points. The first half of one of the 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 odds of winning the "over" in the game were not 50-50 but better than 99% in favor of the "over." The ball player only had a need to win the first half of the parlay to be virtually assured 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 far too smart to permit you to parlay first half to game. If they do allow you to do this, start worrying about collecting because that book will be taken up to the cleaners.
There are, however, some less obvious co-dependent parlays that may 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 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 exactly to use these anomalous side and total combinations to hedge each other and boost your win with hardly any increase in risk. This type of bet, however, needed that you have an opinion on the side or the total. Parlaying is another method to increase your potential win on these games, or even to develop a potential win when you have no opinion.
There are two games this Saturday that qualify. They are 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 will cover the 25 points, they must hold Duke to only 11 points or the overall game will go over the full 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 review. If you want Virginia to cover the spread, and you believe that Duke will not be shut out, in that case your probability 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. Therefore, the probability a parlay of the under with the underdog will win is higher than the normal 25%.
When 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 recently won with the underdog for a winning 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 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 help you to parlay the side to the total in exactly the same game, because a lot more are realizing that these bets are sometimes co-dependent. But, enough books still do allow such bets that you 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.