A stop-loss is not a contract to exit at a price. It is an instruction that becomes a market order the moment the market touches your level. From then on it behaves like every other market order: it fills at the best price available. If the best price available is a long way from your level, that is where it fills.
When the gap appears
Weekend gaps
Friday’s close and Monday’s open are separate prices. News over the weekend is priced in instantly, with no trading in between.
Scheduled releases
A rate decision can reprice an instrument in under a second, straight through any levels sitting in the way.
Unscheduled shocks
Central bank interventions and geopolitical events arrive without a calendar entry.
Thin conditions
Even without news, a large order in a quiet market can clear several price levels at once.
What actually helps
- Size for the gap you can surviveNot for the stop distance you set. The stop is a plan; the gap is a possibility.
- Know your weekend exposureAsk what a 2% adverse gap would do to your account before Friday’s close, not after Monday’s open.
- Treat the calendar as a risk inputHolding a large position through a scheduled release is a decision. Make it deliberately.
- Do not widen a stop mid-tradeMoving a stop away from price converts a defined loss into an undefined one. It is the most expensive habit in trading.
Negative balance protection means a retail account cannot go below zero even after a severe gap. It does not protect the balance itself. See regulation and safety of funds.