A stop-limit order combines two prices: a stop price that activates the order and a limit price that caps the price at which it may be filled. Once the market trades at or through the stop, a limit order enters the book and fills only at the limit price or better.
How the two prices behave
Take a sell stop-limit on EUR/USD with the stop at 1.0850 and the limit at 1.0845, placed while the pair trades at 1.0880.
- Above 1.0850 nothing happens. The order is inactive and invisible to the market.
- When the bid touches 1.0850 the order activates and becomes a working sell limit at 1.0845.
- If liquidity is available at 1.0845 or higher, it fills there or better.
- If the price drops straight through to 1.0838 — a gap, a data release, a thin book — the limit is never available, the order does not fill at all, the position stays open and the loss keeps running as the market moves further away.
The last outcome is normal behaviour, not a platform fault: the limit price is an instruction the platform must respect. The wider the distance between stop and limit, the higher the chance of a fill; the narrower it is, the tighter the worst acceptable price but the greater the chance of no fill.
Stop, limit and stop-limit compared
| Order type | Prices required | What it controls | What it does not control |
|---|---|---|---|
| Stop | One (stop) | Activation level; then becomes a market order | The fill price — any price is accepted |
| Limit | One (limit) | Worst acceptable fill price | Whether it fills at all |
| Stop-limit | Two (stop and limit) | Activation level and worst fill price | Whether it fills at all |
Order life works as with any pending order: day orders expire at the end of the trading day, GTC orders stay until filled or cancelled.
Where the boundary with a stop-loss sits
A stop-limit order is an execution instruction, not a risk control in itself. Using stops to close a losing position, where to place them and how they relate to position size is the subject of the lesson Stop-loss order.
What belongs here is the mechanical difference. A plain stop order accepts any execution price and therefore fills in fast markets. A stop-limit order refuses prices worse than the limit and can therefore leave a position open in exactly the conditions a trader was guarding against. Choosing between them is a choice between price control and execution certainty; the two prices are the whole of the instrument.
