Practice · lesson 21 of 22
How to short on Polymarket, and how to sell before a market resolves
There is no short button on Polymarket because there doesn’t need to be one: betting against an outcome means buying its NO shares, or selling YES on Polymarket US. You can also sell any position before the result at the current bid. How each works, what it costs, and how much you can lose.
In one minute
- To bet against an outcome, buy NO. At a YES price of 60¢, NO costs about 40¢.
- Polymarket US calls selling YES a short: it works exactly like owning NO, and your most you can lose is $1 minus the sale price.
- You can sell shares any time before the market resolves, at the best bid or with a limit order at your own price.
- On event contracts you cannot lose more than you put in; leveraged perpetuals are different.
Shorting means buying NO
Every Polymarket market has a YES and a NO share, and one of them pays $1 at resolution. Their prices add up to about $1: Polymarket’s own example matches a buy order for YES at 60¢ with one for NO at 40¢, because together they make $1 (Polymarket, prices and order book). So if you think YES at 60¢ is too expensive, buying NO at 40¢ is the short. It pays 60¢ profit per share if the outcome doesn’t happen.
Polymarket US says it plainly: selling YES creates a synthetic NO position whose profit and loss work exactly like owning NO, and the maximum loss is $1 minus the price you sold at (Polymarket US, buying Yes vs selling No). Kalshi says the same of its exchange: there is no inherent difference between buying YES and selling NO, or the other way round (Kalshi help centre).
Selling before the market resolves
You don’t have to hold to the result. Polymarket says you may sell shares at any point before a market resolves (Polymarket help centre), in one of two ways:
- Market sell: sells immediately at the best bids on the order book. Fast, but in a thin market the price can slide as you sell more.
- Limit sell: you choose the number of shares and the lowest price you will accept; it fills only when a buyer meets it, possibly in parts.
- Partial sells: you choose how many shares to sell, so you can take some profit and keep the rest.
On Polymarket US the proceeds go straight to your cash balance, and its documentation warns that prices can move quickly as a market nears resolution (Polymarket US, selling early). Selling at the bid means paying the spread; see bid vs ask.
What happens at resolution
When a market resolves, winning shares become redeemable for $1 each and losing shares are worth nothing; trading in that market stops (Polymarket, resolution). Winning shares stay redeemable at any time afterwards. Polymarket’s documentation also describes splitting a dollar into one YES and one NO share, and merging a YES and a NO back into a dollar (Polymarket, positions), which is why the two prices stay close to $1 combined.
How much can you lose?
- Buying YES or NO: at most what you paid, plus fees. A NO bought at 40¢ loses 40¢ if YES happens.
- Selling YES on Polymarket US: at most $1 minus your sale price. Its contracts are fully collateralised, so a short locks up $1 per contract (Polymarket US, collateral).
- Perpetual futures are another product: Polymarket and Kalshi offer leveraged perpetuals, where leverage magnifies losses. Polymarket’s are not available to US users.
Taker fees apply to buying NO the same way as buying YES; see Polymarket fees. To name your price instead of taking the market’s, use a limit order.
See it live on Kalshi
CFTC-regulated event contract exchange
Common questions
Can you short on Polymarket?+
Yes, by buying NO shares, which pay $1 if the outcome does not happen. On Polymarket US you can also sell YES, which its documentation says works exactly like owning NO.
How do I sell my shares on Polymarket?+
Open the position and choose sell. A market sell fills now at the best bids; a limit sell lets you set the lowest price you will accept and fills only when a buyer meets it. You can sell any time before the market resolves.
Can you lose more than you invest on Polymarket?+
Not on its event contracts: the most you can lose is what you paid for the shares, plus fees, or $1 minus your sale price on a Polymarket US short. Leveraged perpetual futures are a different product with different risks.
What happens to my shares when the market resolves?+
Winning shares become redeemable for $1 each and losing shares are worth nothing. Trading in the market stops, and winning shares stay redeemable afterwards.