How stop loss orders work and where they can surprise you
A standard stop loss becomes a market order when the trigger price is reached, which means the fill price can differ from the trigger price. In fast markets or across weekend gaps, the difference can be significant. A stop-limit variant only fills at your limit price or better, which controls the fill price but risks not filling at all if the market moves through the level. Some platforms and account types offer guaranteed stops for a fee; whether any such feature applies to a given broker, product or region must be confirmed directly, not assumed.
- A triggered stop usually fills at the next available price, which may be worse than the trigger level.
- Price gaps at market open or around news can cause fills well beyond the stop level.
- Stop-limit orders control fill price but may not execute in a fast move.
- Whether the trigger uses bid, ask or last price varies by platform and affects when a stop fires.


