Stop order is a conditional order instruction where a stop order becomes an executable order after its trigger condition is met; the trigger price is not a guaranteed fill price.
How it works
The order remains dormant until trigger criteria are met, activating without pre-committing resting liquidity in the visible order book.
Once the trigger condition is met, a Stop-Market order submits a market order prioritizing speed, while a Stop-Limit order submits a limit order protecting price boundaries.
Why it matters
Stop orders are a primary mechanism for automated trade management and risk discipline, helping enforce predetermined plan boundaries.
Stop-Market orders remain vulnerable to slippage and gaps, whereas Stop-Limit orders protect execution price but risk non-fill if the market gaps past the limit; in neither case is the trigger price a guaranteed fill price.
A simple market example
A trader buys stock at $50.00 and sets a Sell Stop-Market order at $47.00 to cap risk. If price falls to $47.00, the order triggers as a market sell for prompt execution against available liquidity.
Common mistakes
Confusing a Stop Order with a Limit Order and expecting a guaranteed fill exactly at the stop trigger price.
Placing stop orders too close to normal market noise, resulting in frequent premature exits before major trend moves.
Frequently asked questions
What is the difference between a Stop-Market order and a Stop-Limit order?
A Stop-Market order triggers a market order (prioritizing immediate execution when liquidity allows, but fill price is not guaranteed). A Stop-Limit order triggers a limit order (guaranteeing price ceiling/floor, risking non-fill).
Can stop orders be used to enter new positions?
Yes. Traders place Buy Stop orders above resistance levels to enter momentum breakouts only after the market proves upward continuation.
Do stop orders protect against overnight gap downs?
No. If a stock closes at $50.00 and opens the next morning at $42.00, a $47.00 stop order triggers at the $42.00 open, realizing a much larger loss than planned.
Educational content only. Definitions describe common market usage and may vary by jurisdiction, instrument, or institution.