A market order is an instruction to buy or sell a contract immediately at the best price currently available.
Last reviewed 4 December 2025 · Educational, not advice
When you place a market order, you are telling the platform to fill your trade right now, taking whatever prices are on offer. It prioritises speed and certainty of execution over price. The trade happens almost at once, but the exact price you pay or receive is not guaranteed in advance.
This is the opposite trade off from a limit order, where you set the price you are willing to accept and wait, accepting that the order may not fill at all. A market order fills now. A limit order fills at your price or not at all. Which one suits you depends on whether speed or price control matters more for the trade in front of you.
The price you actually get on a market order depends on the liquidity sitting in the order book. In a deep, busy market the best available price is close to where the market is trading, and a market order fills cleanly. In a thin market, the best available price can be some distance from the last traded price, and your order can fill at a worse level than you expected.
That gap between the price you saw and the price you got is called slippage. It is the main risk of a market order, and it grows as a market gets thinner or your order gets larger. Near a market close, when liquidity often dries up, slippage can be especially pronounced.
You want to buy a contract showing a last price of forty cents. You place a market order. If plenty of sellers are resting at forty one cents, you fill there, close to what you saw.
But if the book is thin, your order might take the cheapest available contracts at forty one, then forty three, then forty five cents until it is filled. Your average price is higher than the forty cents you first saw. That difference is slippage, and a limit order would have capped the price you paid at the cost of perhaps not filling.
Understanding how these markets work does not make trading safe. Prediction markets can lose you money, and a confident price can still be wrong. Stake only what you can afford to lose, never to chase a loss, and never on borrowed money. If it stops feeling like a free choice, step back. In the United States you can call or text the helpline on 1-800-GAMBLER or visit ncpgambling.org.
It is an instruction to buy or sell a contract immediately at the best price currently available. It prioritises fast, certain execution over price control, so it fills quickly but the exact price is not guaranteed in advance.
A market order fills now at whatever prices are available. A limit order sets the price you will accept and waits, filling at that price or not at all. One favours speed, the other favours price control.
Slippage is the gap between the price you expected and the price your market order actually filled at. It grows in thin markets and on larger orders, and it can be pronounced near a market close when liquidity dries up.
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