Props
A prop bet is a bet on something inside a game other than who wins or the final score. How many yards a quarterback throws for, which team scores first, how long the anthem runs. Props cost more than sides and totals, and they are also where the book is most likely to get a number wrong.
What counts as a prop
Prop is short for proposition. If a bet isn't the spread, the moneyline or the game total, it is probably a prop. There is a shorter answer at what a prop bet is.
- Player props. One player's numbers: passing yards, points, rebounds, strikeouts, shots on goal, whether he scores.
- Game and team props. Things that happen in the game: which team scores first, whether there is overtime, the total for one team or one quarter.
- Novelty props. The coin toss, the length of the anthem, the color of the drink poured on the winning coach. These come out for the biggest games of the year, and whether a book may offer them depends on where it operates.
Most player props are written as an over/under on a number, which makes them a total on one man.
The extra juice
Take a quarterback with a passing line of 249.5 yards.
| Bet | Price | Break-even |
|---|---|---|
| Over 249.5 yards | -115 | 53.49% |
| Under 249.5 yards | -115 | 53.49% |
On a side or a total you usually lay -110 and need 52.38 percent. Here you lay -115 and need 53.49, so the book's cut goes from about 4.5 percent of the money wagered to about 6.5. That is a common prop price, and plenty are worse. I'd check the price on both sides every time: if the over is -130 and the under is +100, the book is telling you where it thinks the number should be.
Some props have only one side. "Player to score a touchdown" is often offered as a yes with no price on the no, and with one price you can't work out the cut at all. A market where you can't see the cut is rarely a cheap one, so I assume it's large and bet accordingly.
Then there are the props with many runners, like first touchdown scorer. Every player is plus money, which looks generous. Convert each price to a percentage and add them up, the way the implied probability page shows, and the total will be well over 100.
Why the limits are low
A book puts more work into the side and total of a big game than into anything else it deals, and the betting on those markets is heavy enough to correct a bad number quickly. That is why it will take a large bet on them.
Props are the opposite. A book may hang hundreds of them on a single game, mostly set by a model, with thin betting on each, and some of those numbers will be wrong. A player who follows one team closely can know something the model doesn't: a role change, a nagging injury, a matchup.
The book knows this, so it protects itself twice over. It charges more juice, and it takes smaller bets; limits on props are a fraction of the limits on sides. A player who beats props regularly will usually find his limits cut further, and quickly (the book watches who wins, and it doesn't watch for long).
So props are the most beatable thing on the board and the hardest to get real money down on. Both are true at once.
The line itself also moves around more between books on props than it does on sides, 249.5 at one and 254.5 at another. Five points of passing yards is a lot of edge to leave lying on the table, and I wouldn't bet a prop without looking at a second book.
How props get graded
At most books a player prop is void if he doesn't take part, but what counts as taking part varies. A player who is active and leaves hurt after one series has usually played, and your over is alive and in trouble.
Props are graded on the official box score. Books usually settle on the numbers as first published and don't regrade for a later correction. Overtime generally counts for player props, though the rule is worth checking for each sport.
Props from one game are also related to each other and to the result, which is why they can only be combined through a same game parlay, at a price the book sets. It matters for your bankroll too. Five props on one team mostly win or lose together, so I'd count them as one bet, and keep that one bet small.
Who they suit
For a recreational bettor, a prop is a reason to watch one player closely, and for a small stake that is fair value, as long as you know you are paying extra for it.
For a serious bettor, props are where an edge is easiest to find and hardest to use. The numbers are softer, the limits are low, and the book prices props high because it knows the least about them. That cuts both ways.