When creating a Trailing Stop order, enter your desired "hard" stop price into the Stop Price field. This acts as a "hard" stop and becomes active as soon as the Trail Stop order is entered.
For example, when creating a Sell Trailing Stop order you want to use a USD 1.00 trailing amount but also want to set an initial "hard" stop price of USD 0.50 from the current bid/ask/last. You will want to enter 1.00 in the "Trail Amount" field and enter a value into the "Stop Price" field that is USD 0.50 less than the price that the contract is currently trading. If the contract's price starts trading higher after the order is entered, then the calculated Trailing Stop sell price will follow by the trailing amount of 1.00 you entered in the "Trail Amount" field. Once the calculated Trailing Stop sell price passes the initial "hard" stop price you entered, then the calculated Trailing Stop price becomes active as the order's new stop price. Please note that the "hard" stop price you entered stays set at that price, so if the contract's price trades lower this "hard" stop will trigger.
If you only want the order to calculate an initial trail stop price from the current Bid/Ask/Last then you only have to use the "Amount" or "%" field and you can leave the "Stop Price" field blank at the time you transmit your Trailing Stop order.
Additional Information
- Trailing Stop in the TWS Users' Guide.
- Trailing Stop orders page of the IBKR website.
- Trailing Stop Study Notes