Trading
Market Order
An order to buy or sell a security immediately at the best currently available price.
Example
Placing a market order to buy 100 shares of a stock fills essentially immediately at whatever the current ask price is, even if that price moved slightly between when you clicked and when the order executed.
Common Misconception
A market order guarantees speed, not price — on a fast-moving or thinly traded stock, the fill price can be noticeably different from the last quoted price you saw.
Why It Matters
For highly liquid stocks and ETFs, market orders are usually fine; for volatile or thinly traded securities, a limit order gives you more control over the price you actually pay.