Prediction market and sportsbook
Polymarket vs BetRivers
Both let you put money on the same game, and they get to their prices in different ways. Which means that several times a day they disagree about who is going to win. Here is what each one is, what each one costs you, and every disagreement between the two that Level has written down.
The two of them, side by side
Polymarket
- What it is
- The same idea as Kalshi and the same $1 contract, on a different exchange with a different crowd trading it.
- Who sets the price
- Also set by whoever is willing to trade, which is why the same game can sit at a different price here than on Kalshi at the same moment.
- What it costs you
- A flat cut of what you put in, whatever the price: $2.00 on a $100 order.
BetRivers
- What it is
- A sportsbook. You are not buying a contract off another person, you are taking a price the book itself is offering.
- Who sets the price
- The book sets the number and moves it to balance what has been bet on each side. It is priced so the book makes money whichever way the game goes.
- What it costs you
- No separate fee. The book takes its cut inside the odds it shows you, so the number on screen is already the number.
Those fees are the ones Level subtracts before showing you a number, worked out by the same code. Nothing on this site quotes a fee it does not also charge against its own figures.
Why they end up disagreeing
BetRivers moves its number to balance the money coming in on each side, because a book makes its living on the spread rather than on picking winners. Polymarket moves because somebody decided a contract was worth more or less than the last person paid for it. Two different pressures, so the two numbers are only ever loosely tied together.
When they drift far enough apart, backing one side on Polymarket and the other side on BetRivers pays back more than the two orders cost, whichever way the game goes. Far enough means after both fees and after the cost of your own order moving the price, which is most of the reason a gap that looks big turns out not to be one.
What we have recorded between these two
414
Gaps found
27.4%
Median gap
43.2%
Biggest gap
Seen so far in WTA, Ligue 1, MLS, Bundesliga, Serie A, UCL, La Liga, EPL, ATP, NFL, NCAAF, MLB, NHL.
- Oct 19Katarzyna Kawa vs Maja ChwalinskaPolymarket + BetRivers28.0%
- Oct 18Stade Rennais @ Strasbourg AlsacePolymarket + BetRivers24.3%
- Oct 18Los Angeles F @ Los Angeles GPolymarket + BetRivers19.4%
- Oct 18Angers @ LorientPolymarket + BetRivers38.0%
- Oct 18FC Köln @ SchalkePolymarket + BetRivers29.3%
- Oct 18Atalanta @ FrosinonePolymarket + BetRivers26.3%
- Oct 18Sporting CP @ LASKPolymarket + BetRivers11.4%
- Oct 18D.C. United SC @ FC CincinnatiPolymarket + BetRivers0.4%
- Oct 18Lazio @ Parma CalcioPolymarket + BetRivers26.7%
- Oct 18Juventus @ LazioBetRivers + Polymarket29.6%
- Oct 18Lens @ Paris FCPolymarket + BetRivers36.3%
- Oct 18Real Madrid @ SevillaBetRivers + Polymarket13.1%
- Oct 18Milan @ AtalantaPolymarket + BetRivers29.5%
- Oct 18Paris FC @ Stade RennaisPolymarket + BetRivers35.4%
- Oct 18Lyon @ NicePolymarket + BetRivers31.5%
- Oct 17Atlanta @ Chicago FirePolymarket + BetRivers30.1%
- Oct 17Kansas City @ AustinPolymarket + BetRivers28.7%
- Oct 17Porto @ EindhovenPolymarket + BetRivers26.3%
- Oct 17Lille @ GalatasarayPolymarket + BetRivers30.8%
- Oct 17Hull City @ BrentfordPolymarket + BetRivers29.8%
The 20 most recent of 414. Each percentage is what the quoted prices implied at the moment we saw them, after both fees and after the cost of your own order moving the price. Nobody placed these, and nothing already written down is ever recalculated. The whole record is on the log.
Before you go looking for one
You need an account at both, funded, before a gap shows up rather than after. Gaps close in minutes and a deposit does not clear in minutes, so an account with nothing in it is the same as no account when one appears.
And a gap is an estimate off public prices at a moment in time, not a guarantee. The price can move while you are placing the second order, and a pair where only one leg filled is an ordinary bet rather than a hedge. The walkthrough runs the whole thing end to end with real numbers, and today’s board is on the front page.
Other pairings
Kalshi vs PolymarketKalshi vs DraftKingsKalshi vs FanDuelKalshi vs BetMGMKalshi vs BetRiversKalshi vs FanaticsKalshi vs CaesarsPolymarket vs DraftKingsPolymarket vs FanDuelPolymarket vs BetMGMPolymarket vs FanaticsPolymarket vs Caesars