Same game parlays
A same game parlay puts several bets from one game on a single ticket. The legs are related to each other, so the book sets the payout itself, and you have no easy way to check it. That is the whole difference from an ordinary parlay, and it is a big one.
Four legs, one game
On an ordinary parlay each leg comes from a different game. A same game parlay, SGP for short, takes all its legs from one: the favorite to cover, the game to go over, the quarterback to throw for 250 yards, a receiver to score. The rule is the same as any parlay. Every leg has to win, and three out of four pays nothing.
For a long time books would not take these bets at all. Now they are on the front of most betting apps, and the reason for both is the same thing: correlation.
Why the legs travel together
Two bets from different games have nothing to do with each other. Two bets from the same game usually do. If the favorite wins by three touchdowns, its quarterback probably had a good day, and the game probably went over the total, so a bettor who could parlay those at the ordinary price would be getting paid as though they were separate coin flips when they are closer to one bet made three times.
That is why books used to refuse. What changed is that they learned to price the relationship: the book estimates how much the legs move together, cuts the payout to match, and then takes its margin on top.
A price you can't check
Take two legs that are each -110. From different games, the multiplication is simple and a $100 parlay wins $264. You can check that on a parlay calculator in ten seconds.
From the same game, the book might offer +220 on that pair. I've made that figure up to show the sum, and the real one changes with the legs and the book.
| A $100 bet wins | Both legs must come in | |
|---|---|---|
| Ordinary parlay, two legs at -110 | $264 | 27.4% of the time |
| The same two legs as an SGP at +220 | $220 | 31.25% of the time |
Is +220 fair? It is if the two legs come in together more than 31.25 percent of the time once you allow for how they are related. To know that, you would need the book's own estimate of the relationship, and you don't have it. The book has a model and years of results. You have a feeling that the quarterback plays well when his team wins.
On a straight bet you can work out the cut from the two prices. On a same game parlay there is nothing to work it out from, and anyone who prices bets for a living would love every market to be like that. I know I would have.
What the book makes
I can't give you a single figure, because it is different for every combination and no book publishes it. I can show you where it starts.
Most of the legs in an SGP are props, and props carry more juice than sides; a common price is -115 both ways. Put four of those together, even with no relationship between them at all, and the arithmetic looks like this.
| Four-leg parlay | A $100 bet wins | Fair payout | The book's cut |
|---|---|---|---|
| Legs at -110 | $1,228 | $1,500 | 17.0% |
| Legs at -115 | $1,122 | $1,500 | 23.6% |
So before any adjustment for related legs, the usual raw material of a same game parlay already costs more than an ordinary parlay. The correlation pricing goes on top, where you can't see it. It is generally one of the most expensive bets on the menu, and it is one of the bets books advertise hardest (those two facts are not a coincidence). Every leg you add is another margin stacked and another way to lose, so if I bet one at all, I'd keep it short.
The house rules
- A leg is voided. If a player in your parlay doesn't play, books differ. Some void the whole ticket. Some drop the leg and reprice what is left. Find out which before you build a ticket around one player.
- Blocked combinations. The book won't let you combine some legs, usually ones so closely tied that they are nearly the same bet.
- Maximum payout. Long tickets can run into the cap. It is in the house rules.
- Boosts and insurance. These are marketing, attached to the bet where the book makes most. Work out what the ticket is worth without the offer.
Is there ever an edge
In theory, yes: when the book underestimates how strongly two legs go together. People who find those spots do it with their own data, and the book limits them quickly once it notices. For someone betting on a Sunday afternoon with a phone, I would not go looking for it.
What I'd do instead is treat it as entertainment and stake it that way. A few dollars for a sweat that lasts the whole game is a fair deal if you know the price is against you. Never raise the stake on one to win back a losing day, because this is the worst bet in the shop to chase with. And if you have a real opinion on a game, bet it straight, where you get a price you can check.