What is a market order?
A market order lets you purchase or sell a financial asset immediately at the best price currently available.
A market order lets you purchase or sell a financial asset immediately at the best price currently available. However, the last-traded price is not necessarily the price at which a market order will be executed, possibly incurring slippage.
Slippage is the difference in price from the market price at the time of placing your order and the average fill price once the order is completed.
The main advantages of market orders over limit orders are their simplicity, immediacy, and ability to, in most cases, completely fill.