What is a Market Order? 175 September 15, 2021 A market order is designed to be executed immediately. It is meant to buy or sell at the best available price in the order book (which you can view before placing an order). Note that this is different from the last traded price. A common mistake is to think the last traded price is what you will get when placing a market order. The order book can change significantly since the last traded price, especially in less popular trading pairs. An order book consists of all traders’ limit orders (see image below) for that trading pair.The drawback of a market order is that you’re not guaranteed the exact price you’re trying to buy or sell at. It all depends on what is available in the order book when your order is being executed.