Are the exchanges cheaper than the sportsbook?
28 upcoming games priced on DraftKings, Kalshi and Polymarket. With the vig removed, the exchanges sell the same outcome below the book's fair price 22 times out of 56, above it 19 times. Mean book hold 4.5%. Updated every ten minutes.
Publishing this? The whole table is a free download: CSV, refreshed every ten minutes. Credit "data: VenueGap" with a link.
Biggest exchange discounts to the book right now
| Outcome | DraftKings fair | Kalshi | Polymarket | Discount | Cheaper |
|---|---|---|---|---|---|
| Magic Magic vs. Raptors · NBA games | $0.39 | $0.36 | $0.37 | +$0.04 | Kalshi cheaper |
| Pacers 76ers vs. Pacers · NBA games | $0.40 | $0.38 | $0.38 | +$0.03 | Polymarket cheaper |
| Mavericks Thunder vs. Mavericks · NBA games | $0.36 | $0.33 | $0.34 | +$0.03 | Kalshi cheaper |
| Bucks Rockets vs. Bucks · NBA games | $0.27 | $0.26 | $0.27 | +$0.02 | Kalshi cheaper |
| Hawks Heat vs. Hawks · NBA games | $0.59 | $0.57 | $0.57 | +$0.02 | Kalshi cheaper |
| Sharks Sabres vs. Sharks · NHL games | $0.43 | $0.42 | $0.42 | +$0.01 | Kalshi cheaper |
| Warriors Warriors vs. Timberwolves · NBA games | $0.42 | $0.41 | $0.41 | +$0.01 | Kalshi cheaper |
| Trail Blazers Trail Blazers vs. Lakers · NBA games | $0.47 | $0.47 | $0.47 | $0.00 | same |
| Timberwolves Warriors vs. Timberwolves · NBA games | $0.58 | $0.59 | $0.60 | $0.00 | same |
| Lakers Trail Blazers vs. Lakers · NBA games | $0.53 | $0.54 | $0.54 | $0.00 | same |
| Sabres Sabres vs. Sharks · NHL games | $0.57 | $0.57 | $0.59 | $0.00 | same |
| Rockets Rockets vs. Bucks · NBA games | $0.73 | $0.74 | $0.74 | −$0.01 | book cheaper |
| 76ers 76ers vs. Pacers · NBA games | $0.60 | $0.62 | $0.63 | −$0.02 | book cheaper |
| Heat Heat vs. Hawks · NBA games | $0.41 | $0.43 | $0.43 | −$0.02 | book cheaper |
| Thunder Thunder vs. Mavericks · NBA games | $0.64 | $0.67 | $0.67 | −$0.02 | book cheaper |
| Raptors Magic vs. Raptors · NBA games | $0.61 | $0.64 | $0.64 | −$0.03 | book cheaper |
By league
| League | Outcomes | Exchange cheaper | Mean discount |
|---|---|---|---|
| NBA games | 26 | 46% | $0.00 |
| college football games | 12 | 33% | $0.00 |
| NHL games | 10 | 40% | $0.00 |
| Ligue 1 games | 4 | 25% | $0.00 |
| La Liga games | 2 | 50% | $0.00 |
| Bundesliga games | 2 | 0% | $0.00 |
What does "fair price" mean here?
A sportsbook moneyline includes the book’s margin (the vig or hold). Converting both sides of a market to implied probabilities gives a total above 100%; dividing each by that total removes the margin. The result is what the book itself thinks the outcome is worth, before it charges you.
Why compare it to Kalshi and Polymarket?
The exchanges are order books: the price is what other traders will sell at, with no built-in margin, only a small fee on winnings. When an exchange price sits below the book’s fair price, the same outcome is being sold cheaper than the sportsbook’s own estimate.
Is a positive number a guaranteed edge?
No. Exchange fees, the bid–ask spread, and the fact that DraftKings may simply be wrong all apply. It is a comparison of prices, not advice.
Where do the sportsbook prices come from?
DraftKings moneylines as published through ESPN’s public scoreboard, refreshed every ten minutes for games in the next three days. If that feed is unavailable, the column is blank.
Data: DraftKings via ESPN, Kalshi and Polymarket mids. Not affiliated with any of them. Pro alerts include the same gaps against the exchanges; sportsbook alerts are next.