Checked against Polymarket’s documentation on prices and help on selling early on 13 October 2026.
The short answer
The price on the screen is not the price you sell at. Polymarket shows the midpoint between the best buy and sell offers (or the last trade, if they are more than 10¢ apart). An instant sale goes to the buy orders that are waiting, starting with the best one, so you get the bid, not the midpoint. Then the fee is taken from what you receive. A large sale can also reach lower bids, and on sports markets the price can move during the 3-second wait.
To see what your sales and buys cost in fees over the last 30 days, type your Polymarket @name or paste your address into the free check above.
Four reasons, with numbers
Say a sports market shows 71¢. The best buy order waiting is 70¢ for 100 shares, the next is 68¢ for 100 shares, then 65¢ for 300 shares. You sell 300 shares at once. This is an example, not a real market.
- 1. Bid, not midpoint. 300 shares at 71¢ would be $213.00. The first 100 go at 70¢.
- 2. A big sale goes down the list. The next 100 go at 68¢ and the last 100 at 65¢. Together: $70 + $68 + $65 = $203.00.
- 3. The fee on the sale. 0.05 × shares × price × (1 − price) for each part: $1.05 + $1.09 + $1.14 = $3.28. You receive $199.72.
- 4. The price can move before the sale goes through. On sports markets instant orders wait 3 seconds before they are matched, and an order can be turned down at the end of that wait (Polymarket help).
So the screen said $213, and $199.72 arrived: $10.00 from the bids and $3.28 from the fee.
When only part of an order goes through
If there are not enough buy orders at acceptable prices, only part of a sale (or a buy) may go through, and the rest stays in your position. That can look as if money went missing, until you see that some shares were not sold. Check the trade in your activity before you count the result.
How to get closer to the price you see
- Sell with an order at your own price. It waits for a buyer, pays no fee and gets a share of other traders’ fees. It may not sell, and on sports markets open orders are cancelled when the game starts.
- Look at the buy orders before a large sale. The order book shows how many shares are wanted at each price.
We don’t say whether to sell or hold; that is your call. What each choice costs is in cashing out early on Polymarket and does Polymarket charge a fee when you sell?
Questions
Why did Polymarket pay me less than the price shown?
The price shown is the midpoint between offers, but an instant sale gets the best waiting buy order, and a large sale also reaches lower ones. The fee on the sale is then taken from what you receive.
Is there a fee when I sell on Polymarket?
Yes, on an instant sale: shares × rate × price × (1 − price), taken from the proceeds. A sell order at your own price that waits for a buyer pays nothing.
Why does my position show a loss after I sold at a profit?
Often because the sale price was lower than the price on the screen, and the fees on the buy and the sale came on top. The profit on your profile also does not take out fees, so it can differ from the money that arrived.