What is a Market Order?
A market order is an instruction to execute a trade immediately at the best available price. It guarantees execution but not the exact price. For highly liquid stocks like Apple or Microsoft, the difference between the quoted price and the execution price (slippage) is usually just a penny or two. However, for thinly traded securities, slippage can be significant.
When to Use Market Orders
Market orders are best suited for liquid, large-cap stocks where the bid-ask spread is narrow, typically under $0.05. They are also appropriate when speed of execution matters more than price precision, such as when exiting a position during a fast-moving selloff. For a stock trading at $150 with a 1-cent spread, a market order will execute almost exactly at the displayed price.
Key Considerations
Avoid placing market orders during pre-market or after-hours sessions, when liquidity is thin and spreads widen dramatically. A stock that closed at $50 might show a pre-market bid of $48 and an ask of $52, meaning a market buy order could fill $2 above the previous close. For volatile or illiquid securities, limit orders provide much better price control.