Glossary · Orders & trading · Beginner-friendly
Stop-loss order
In plain English
A stop-loss is an order that tries to sell for you after price hits a danger level. It can limit damage, but in a sudden gap you may still get a worse price than the stop.
Everyday analogy: Like a fire alarm that opens the exit - you get out, but you don’t choose the exact second you step outside.
Try this on StockWatch
Click through real pages. Learning sticks better with examples you can see.
Why it matters
Stops turn a vague “I’ll get out if I’m wrong” into an instruction - but gaps and thin books still matter.
A bit more detail (optional)
How it works
When the stop price is reached, the order typically becomes a market order. In a fast gap, you may fill worse than the stop - especially overnight or in thin names.
Where people go wrong
Stops that are too tight get shaken out by normal noise. Stops that are too wide fail to protect capital. Place them from the thesis (invalidation), not from round-number superstition.
How to practice on StockWatch
Open a liquid quote, note recent volatility, and ask where your thesis is actually invalidated - then compare that level to a tight “noise” stop.
Simple examples
Gap through the stop
You set a stop at $48. Bad news gaps the stock open at $44. The stop triggers, but the fill is near $44 - not $48.
Overnight gap
Stop at $50; stock opens $46 on bad news. The order triggers as a market sell and fills near the open - risk limited, not surgically precise.
Easy mistakes to avoid
- Expecting the exact stop price as a guaranteed fill
- Setting stops so tight that normal noise knocks you out
- Expecting an exact fill at the stop price in a gap
- Parking stops at obvious round numbers everyone else uses
- Using a stop as a substitute for position sizing
Remember: A stop limits risk; it does not promise your exact exit price.