Baseball
Where MLB prices disagree.
MLB is priced two different ways at the same time: traders set it on Kalshi and Polymarket, and the sportsbooks set it themselves. When the two disagree far enough to survive the fees, it lands here.
Where MLB gets priced
- Prediction markets
- Kalshi and Polymarket
- Sportsbooks
- DraftKings, FanDuel, BetMGM, BetRivers, Fanatics, Caesars
What we have recorded
21
Gaps found
0.6%
Median gap
3.9%
Biggest gap
- Oct 2Atlanta @ Los Angeles DPolymarket + BetRivers0.2%
- Sep 27Colorado @ Chicago WSPolymarket + BetRivers1.4%
- Sep 25Baltimore Orioles @ New York YankeesPolymarket + Fanatics0.7%
- Sep 24Pittsburgh @ DetroitKalshi + Polymarket0.2%
- Sep 24Colorado @ Chicago WSPolymarket + Kalshi0.2%
- Sep 23Milwaukee @ PhiladelphiaKalshi + FanDuel0.3%
- Sep 19Atlanta @ HoustonKalshi + BetRivers1.5%
- Sep 19Washington @ St. LouisPolymarket + Caesars0.6%
- Sep 19Atlanta @ HoustonPolymarket + Fanatics0.6%
- Sep 19Milwaukee @ BaltimorePolymarket + FanDuel0.8%
- Sep 18Toronto @ TexasPolymarket + BetRivers0.6%
- Sep 17Minnesota @ Los Angeles AKalshi + BetRivers0.7%
- Sep 16San Francisco @ Los Angeles DPolymarket + Kalshi0.1%
- Sep 15Miami @ ArizonaPolymarket + Caesars1.8%
- Sep 12San Diego @ San FranciscoCaesars + BetRivers1.1%
- Sep 11Philadelphia @ AtlantaPolymarket + FanDuel0.2%
- Sep 9Washington @ San DiegoKalshi + BetRivers3.9%
- Sep 8Texas Rangers @ Seattle MarinersPolymarket + FanDuel0.5%
- Sep 6Cincinnati @ Los Angeles DPolymarket + FanDuel0.5%
- Sep 5Washington @ Los Angeles DPolymarket + BetRivers0.4%
- Sep 5Tampa Bay @ TexasPolymarket + BetRivers0.5%
Every percentage is what the quoted prices implied at the moment we saw them, after fees and after the cost of your own order moving the book. Nobody placed these, and nothing already written is ever recalculated. The whole record across every sport is on the log.
Reading an MLB gap
A gap means backing one side on a prediction market and the other side at a sportsbook, splitting a stake between them so both outcomes pay back more than you put in. The percentage is what is left after Kalshi’s per-contract fee, Polymarket's 2%, and the price movement your own order causes, with the rounding running against the estimate.
It is an estimate from public prices at a moment in time, not a guarantee. A gap can close while you are placing the second order, and a half-filled pair is a one-sided bet rather than a hedge. The walkthrough runs the arithmetic end to end, and today’s live MLB board is on the front page.
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