A Stop order becomes a market order to buy or sell securities or commodities once the specified stop price is attained or penetrated. A Stop order is not guaranteed a specific execution price, and may execute significantly away from its stop price.
there is a lot more to stop orders than might seem at first - and you might want to check up first hand with IB on the technicals of exactly how IB handels stop orders to avoid an expensive problem in the future
its a key issue and you might get free advice now fro here that will cost you a lot of money later
study exactly how IB operates stops - i am not a fan of stops - but if you are going to have one - make sure you understand the fundamentals of correctly instigating it
It will depend on which type of stop you are using. If you use something like the 'double bid/ask' then there is the possibility that you stop will not fire if there are NOT two consecutive bids/asks at your stop price.
So to be safe, you would need to select the 'last' option which relies on just one price to trigger the stop.
The following is IB's wording of the types of stops:
If "Last" is selected, stop orders will be triggered based on the last price. For example, for a sell order, there must be one last price that is less than or equal to the trigger price.
If "Double last" is selected, stop orders will be triggered based on two last prices. For example, for a sell order, there must be two consecutive lasts that are less than or equal to the trigger price to trigger the order.
If "Double bid/ask" is selected, stop orders will be triggered based on two bids or asks. For example, for a sell order, there must be two consecutive asks that are less than or equal to the trigger price to trigger the order.
If "Default" is selected, then the double bid/ask method will be used for orders for OTC stocks and US options. All others orders will use the last method.
Another thought - on the Stop Trigger Configuration screen right at the bottom there is the option to 'Allow triggering outside of regular trading hours'.
If this is unticked, then your stop will not trigger if the price goes to your stop outside of normal trading hours. So just to be safe, tick the box as long as you don't mind being stopped out overnight if the need arises.