Markets Prediction
Get Promotion Codes
Jump toBest PlatformsLive Odds

Market Order

A market order is an instruction to buy or sell a prediction market contract immediately at the best available price, consuming existing resting orders on the order book. It prioritizes speed of execution over price certainty.

Updated June 25, 2026Market Mechanics
TL;DR
Buy or sell right now at whatever the current price is. Market orders guarantee a fill but expose you to slippage when liquidity is thin.

Key Points

✓A market order executes immediately by matching against the best resting [[limit-order]] on the opposite side of the [[order-book]].
✓You pay the ask price when buying and receive the bid price when selling, meaning you always cross the [[bid-ask-spread]].
✓In low-[[liquidity]] prediction markets, a large market order can sweep multiple price levels, causing significant [[slippage]].
✓Market order placers are classified as takers in the [[maker-taker]] fee model and typically pay higher fees than limit order makers.
✓Market orders are best suited to high-urgency situations where immediate execution outweighs the cost of crossing the spread.

How Market Orders Execute

When you submit a market order, the Matching Engine immediately scans the opposite side of the Order Book for the best available resting orders. A buy market order matches against the lowest-priced ask; a sell market order matches against the highest-priced bid. If your requested quantity exceeds what is available at a single price level, the engine walks up (or down) the book, filling against successively worse prices until the order is complete. This price walk is what produces Slippage: your average fill price differs from the price shown when you submitted the order. On Kalshi, market orders are categorized as taker orders and incur higher Trading Fees than Limit Order placements.

When to Use Market Orders in Prediction Markets

Market orders are appropriate when entering or exiting a Position quickly matters more than saving a few cents per contract. Breaking news events, late-stage markets approaching Market Resolution, or fast-moving sentiment shifts can all create situations where the cost of not trading outweighs the cost of crossing the Bid-Ask Spread. However, on thinly traded prediction markets, market orders carry real risk: a large order on a shallow book can move the price significantly against you before the Order Fill completes. Experienced traders often prefer Limit Order placements even in urgent conditions, using prices just inside the current spread to get fast fills at a controlled cost.

Related Terms

Limit Order
A limit order is an instruction to buy or sell a prediction market contract at a specific price or better, resting on the order book until a counterparty matches it or the order is cancelled. Unlike a market order, it guarantees a price but not an immediate fill.
Slippage
Slippage is the difference between the price a trader expects to pay (or receive) for an event contract and the actual price at which the order is filled, caused by insufficient liquidity at the desired price level. It is most common on large orders or in thin markets.
Bid-Ask Spread
The bid-ask spread is the gap between the highest price a buyer is willing to pay (the bid) and the lowest price a seller is willing to accept (the ask) for an event contract. This gap represents an implicit transaction cost every trader pays when entering or exiting a position.
Maker and Taker
The maker-taker model is a fee structure used by prediction market exchanges that charges different rates based on whether an order adds liquidity to the order book (maker) or removes it (taker). Makers place resting limit orders; takers fill those orders with market or aggressive limit orders.
Order Fill
An order fill is the execution of a buy or sell order in a prediction market, confirming that the specified quantity of contracts has been matched with a counterparty at an agreed price. Orders can be fully filled, partially filled, or left unfilled depending on available liquidity.

Find the best odds on every market

Compare live prices across Kalshi, Polymarket, and more — spot arbitrage and trade the sharpest line on any event.

Compare Markets