PREDICTION MARKETS
Polymarket and Kalshi Arbitrage vs. Bookmakers
Polymarket and Kalshi price by trading, not analysts, diverging from bookmakers more often and longer. 642K Polymarket surebets in 30 days.
A prediction market is an exchange where an outcome's price comes from traders' deals: a “Team A wins” contract trades between $0 and $1, and a price of $0.45 means odds of 2.22. There's no analyst moving the line after every round. So the price reacts to the match more slowly than a bookmaker's and diverges from it more often. From September 6 to October 6, 2026, Dozor found 642,253 surebets involving Polymarket and 138,017 involving Kalshi: Polymarket is part of 13% of all surebets in the scanner.
Who Polymarket forms surebets with
| Pair | Surebets in 30 days | Over a minute | Median life |
|---|---|---|---|
| Olimp and Polymarket | 135,476 | 7,738 | 6.1 s |
| Duel and Polymarket | 80,260 | 11,062 | 4.2 s |
| 1xBet and Polymarket | 69,719 | 5,437 | 4.0 s |
| BetBoom and Polymarket | 39,014 | 3,849 | 6.4 s |
| Marathon and Polymarket | 37,755 | 2,575 | 6.1 s |
| Polymarket and Winline | 36,867 | 3,043 | 4.1 s |
The median lifetime of a surebet involving Polymarket is 4.1 seconds; for live surebets across the whole scanner it is 2.0. 8.3% of Polymarket surebets last longer than a minute versus 4.5% on average, and the Duel–Polymarket pair produces the most long-lived ones: 11,062 in 30 days. Kalshi had 138,017 surebets over the same period with a median lifetime of 4.0 seconds, most often paired with Olimp, 1xBet and Duel.
How an exchange differs from a bookmaker
- No per-player limits. An exchange doesn't restrict arbitrage bettors' accounts: it earns from fees, not from customers' losses. There's one constraint: order book depth, that is, how many contracts are available at the price you need. Dozor shows it and offers a minimum-depth filter.
- Priced in dollars, settled in crypto. Polymarket runs on USDC; Kalshi runs in US dollars for US residents. The exchange rate, the platform fee and the bid-ask spread are all included in the ROI calculation.
- Separate market settlement rules. An exchange contract is defined in text: what counts as a win, what happens if the match is cancelled. It may differ from a bookmaker's rules for the same match.
- Execution is a trade, not a bet. You can buy a contract at the price you need as long as there's volume in the order book. A large amount will move the price.
How Dozor works with exchanges
Polymarket and Kalshi are connected like regular books: their contracts are mapped to the same markets as bookmaker lines and take part in the surebet search on equal terms. In the card, the exchange leg shows the contract price, the equivalent odds and the order book depth. The minimum order book depth filter cuts out surebets you can't get into with the stake you need.
Frequently asked questions
Are there direct surebets between Polymarket and Kalshi?
Both markets trade the same major events, and discrepancies between them do happen. In esports, most of Polymarket's surebet volume is against bookmakers, not against Kalshi.
Why do exchange surebets live longer?
The price is moved by traders, not by a bookmaker's algorithm. Until someone places a new order, the old price stays.
What is order book depth?
The volume of contracts available at the price the surebet was calculated from. See the term in the glossary.
Live figures for Polymarket and its pairs are in the Bookmakers section.
Data on this page: Dozor surebet history from 17:21 UTC on September 6 to 11:58 UTC on October 6, 2026, 4,871,476 surebets. A breakdown of the mechanics with calculations is in the article on arbitrage between Polymarket, Kalshi and bookmakers.