Market Order

What Is a Market Order?

A market order is the most basic type of trade instruction. It tells the broker or exchange to execute a buy or sell transaction immediately at the best available price. Market orders prioritize speed of execution above all else. You will get filled, but you may not get the exact price you see on the screen at the time you click the button.

When you submit a market buy order, it is matched against the best available sell orders (asks) in the order book. A market sell order is matched against the best available buy orders (bids). In highly liquid securities like major ETFs and large-cap stocks, the difference between the expected and actual fill price is typically minimal.

How Market Orders Work

The execution process involves your order interacting with the order book. If you place a market buy order for 100 shares and there are 500 shares offered at the best ask price, your order fills entirely at that price. However, if there are only 50 shares at the best ask, 50 shares fill at that price and the remaining 50 fill at the next available price level, which may be slightly higher. This process is called walking the book.

In practice, retail market orders in liquid stocks fill very close to the quoted price. Institutional market orders for large blocks may experience more price impact due to their size.

Market Order vs. Limit Order

The fundamental tradeoff between market and limit orders is certainty of execution versus certainty of price. A market order guarantees you get filled but not at what price. A limit order guarantees you will not pay more than your specified price but does not guarantee execution.

For everyday trading in liquid markets, market orders are perfectly adequate and offer the convenience of immediate execution. For less liquid securities, volatile conditions, or when precise price matters, limit orders provide better control over execution quality.