A trader holding Yes contracts on Kalshi or Polymarket watches the price move against the position and sells back for less than paid, eating the loss without checking a sportsbook first. The other option is betting the opposite side at a sportsbook for the exact stake that locks the same profit no matter how the market resolves.
The number that matters is how much to bet on the other side, and what profit locks in either way. Enter the position and the sportsbook price on the other outcome, and compare that locked profit against simply selling the contracts back on the exchange.
Start with the number of Yes contracts held, then the price paid per contract in cents. Select the exchange, since Kalshi, Polymarket, Robinhood, and no-fee platforms each charge a different amount on the way in, and that fee changes the outlay the hedge has to cover. Last, enter the sportsbook’s odds on the opposite outcome.
The result shows the position’s total outlay including the fee, the exact stake to bet at the sportsbook, and the profit if the outcome lands Yes and if it lands No. When those two profit figures match, that’s the locked profit, the amount that comes out no matter which side wins.
With 100 Yes contracts bought at 45 cents on Kalshi, the raw cost is $45. Kalshi’s fee adds to that, bringing the total outlay to $46.74. Each contract pays exactly one dollar if Yes happens, so 100 contracts are worth $100 on a Yes outcome and worth nothing on a No outcome unless the other side is covered.
At -110 on the No side, the decimal odds are 1.909. Dividing the 100 contracts by 1.909 gives a stake of $52.38, sized so a No win returns $100, the same amount the contracts would have paid on a Yes win. Whichever way the market resolves, the payout is $100 against a combined cost of $46.74 outlay and $52.38 hedge, leaving $0.88 locked in either way.
This matters once the sportsbook price on the other side has moved enough that the guaranteed profit beats what selling the contracts back on the exchange would return. A price gap that looks wide on the surface can shrink fast once the exchange fee is added to the outlay, so the fee is not optional in the comparison.
The common mistake is picking a round hedge amount that feels safe instead of the exact stake the math calls for, which leaves one outcome paying more than the other instead of locking a flat number. Ignoring the fee is the second mistake, since it quietly eats into what looked like a bigger edge.
A sharp bettor runs the exact stake, checks that the profit is the same on both sides, and only then compares that locked number against the price the exchange is currently offering to close the position outright. If selling back pays more than the hedge locks in, selling back wins.
Does the exchange fee change the sportsbook stake needed? It changes the outlay, not the formula for the stake itself, since the stake is set by the number of contracts and the sportsbook’s decimal odds. But a higher outlay from the fee lowers the locked profit, so it has to be included before deciding whether hedging beats selling back.
Why would a bettor hedge instead of just selling the contracts back on the exchange? Selling back locks in whatever the current exchange price offers right then, while hedging at a sportsbook locks in a profit based on that sportsbook’s price on the opposite outcome. Whichever number is higher is the better exit.
Can the profit differ between the Yes and No outcomes? It can if the stake isn’t sized correctly for the sportsbook’s odds. A properly sized hedge produces the same profit regardless of outcome, which is the entire point of running the numbers instead of guessing a stake.
What if the sportsbook doesn’t offer a close enough price on the other side? If the gap between the exchange price and the sportsbook price is too small to clear the fee, the hedge won’t add up to a real profit, and selling the contracts back on the exchange is likely the better move.