The Southern Line
Prediction markets vs sportsbooks for SEC football: where the price comes from
A sportsbook sets a line and charges vig. A prediction market lets fans trade against each other and charges a fee, or nothing. Here is what that means for a $100 position on an SEC game.
Every Saturday in the SEC there are two kinds of venue quoting a price on the same game, and they get to that price in opposite ways.
How a sportsbook prices a game
A sportsbook posts a line and takes the other side of every ticket. To make money whatever happens, it shades both sides: a true coin flip gets listed at -110 and -110 instead of +100 and +100. That shading is the vig, or hold. On a standard -110/-110 line the book's hold is about 4.5%: of every $100 traded on each side, roughly $4.50 is the book's margin before a down is played.
The hold is not a fee you see. It is baked into the price, which is why two books quoting "the same" line can pay out different amounts.
How a prediction market prices a game
A prediction market does not take the other side. It matches a fan who thinks Georgia wins with a fan who thinks Georgia loses, and the price is wherever those two orders meet, expressed as a probability. A contract on Georgia at 70 cents pays $1 if Georgia wins. Nobody shades the line, because there is no house position to protect.
The venue earns its money differently:
- Novig charges no vig and no trading fee on the position itself. The price you see is the price you get.
- Kalshi charges a taker fee of about 7% of the expected profit on each fill, highest on a coin flip and shrinking as a side becomes a heavy favorite.
- Polymarket US charges a per-market fee on the same shape, currently around 3 to 5% depending on the market.
What a $100 position returns
Take a game where Novig has the home side at -150, equivalent to 60 cents a contract.
| Venue | Quote | What $100 returns in profit |
|---|---|---|
| Novig | -150 | $66.67 |
| Sportsbook at -160 | -160 | $62.50 |
| Exchange at 60¢ with a 7% fee | 60¢ | about $64.90 |
The book is cheaper to understand and more expensive to use. The exchange with a fee lands in between. Novig is the cleanest comparison because nothing is hidden in the price and nothing is added on top.
That is the number the board on this site shows for every SEC game: the profit on $100 at each venue, sorted best first, with how far each one sits behind the best price.
Why this matters more in the SEC footprint than anywhere else
Of the twelve states with an SEC campus, five have no legal sportsbook at all (Texas, Georgia, Alabama, South Carolina, Oklahoma), one allows wagering only inside a casino (Mississippi), and one has a single app (Florida). For most SEC fans the sportsbook column on the board is a price they cannot take. The prediction-market column is the one they can.
Novig is a CFTC-designated exchange and operates in 47 states, including every SEC state. See the state pages for exactly what is and is not available where you live.
What "no vig" does not mean
No vig does not mean a free lunch. The price on Novig is set by other traders and moves with the market, and a thin market can have a wider spread between the best buy and sell than a sportsbook's hold. Where that is true for a given game you will see it in the board: Novig's hold column reports the gap between its two sides the same way it does for a book. Most SEC games are liquid enough that the figure sits near zero, but the board does not assume it.
