The Atlantic Line
Prediction markets vs sportsbooks for ACC football: where the price comes from
A sportsbook sets the line and keeps a margin. A prediction market matches fans against each other and charges a fee, or none. Here is what that does to a $100 position on an ACC game.
On any ACC Saturday, two very different kinds of venue are putting a price on the same game. They arrive at that price from opposite directions, and the difference shows up in what a fan gets paid.
The sportsbook model
A sportsbook writes the line itself and stands on the other side of every ticket. To come out ahead no matter who wins, it tilts both sides in its own favor: a game it rates as a true coin flip goes up at -110 each way rather than +100 each way. That tilt is the vig, also called the hold. On a -110/-110 market it comes to roughly 4.5% of everything taken in on both sides, kept by the book before the opening kickoff.
You never see the vig as a line item. It lives inside the odds, which is why two books listing "the same" Clemson spread can pay different amounts on it.
The prediction-market model
A prediction market does not take a side. It pairs a fan who thinks Miami covers with a fan who thinks it does not, and the price is wherever their orders meet, quoted as a probability. A contract on Wake Forest at 62 cents pays $1 if Wake Forest wins. With no house position to protect, nobody is tilting the line.
These venues get paid in other ways:
- Novig takes no vig and adds no fee on top of the contract price. What is quoted is what you pay.
- Kalshi takes a fee on each fill, calculated from a 7% rate times the price times one minus the price. It is largest on a coin flip and shrinks as one side becomes a heavy favorite.
- Polymarket US sets a fee market by market on a similar shape.
What $100 returns
Take an ACC game where the home side trades at -150 on Novig, the same as 60 cents a contract.
| Venue | Quote | Profit on a winning $100 |
|---|---|---|
| Novig | -150 (60¢) | $66.67 |
| Exchange at 60¢ with a 5% fee rate | 60¢ | $63.40 |
| Sportsbook | -160 | $62.50 |
| Exchange at 60¢ with a 7% fee rate | 60¢ | $62.13 |
The sportsbook is the easiest to read and among the more expensive to use. The exchanges with fees land in a band depending on the rate. The no-fee venue is the cleanest comparison, because there is nothing hidden in the price and nothing added after it. That profit-on-$100 figure is what the board shows for every ACC game, best first, with each venue's distance from the top. The board explainer walks through the math.
Why the ACC map makes this matter
The ACC stretches across eleven states, and the sportsbook column is not available in several of them. Texas (SMU), Georgia (Georgia Tech), South Carolina (Clemson) and California (Cal and Stanford) have no legal sportsbook app. Florida, home to Florida State and Miami, has a single one: Hard Rock. For a large share of ACC fans, the book prices on the board are prices they cannot take.
Novig is a CFTC-designated prediction market available in 47 states. The three it does not serve are Arizona, Michigan and Nevada, so it is open in every state with an ACC campus. The state pages spell out what is available where you live, including Texas, Georgia, South Carolina, California and Florida.
What "no vig" does not mean
No vig is not the same as a guaranteed better price. Novig's prices are set by the traders on it and move with the market. A thinly traded game can show a wider gap between the best buy and the best sell than a sportsbook's hold, and when that happens the board shows it: Novig's hold column is calculated the same way as every book's. On most ACC games with real volume that figure sits close to zero, but the board reports it rather than assuming it.
