A stop-limit order can be broken down into a stop order and a limit order. The stop price is the price at which the limit order is triggered. Once your stop-limit order is triggered, the order goes onto the order book as a limit order.
What is a stop-market order?
A stop-market order is a lot like a stop-limit order, but rather than going onto the order book, a stop-market order is executed immediately as a market order.
During times of high volatility when the market price rises or falls sharply, the final transaction price of a market order may be higher or lower than the last transaction price that was displayed on the page when you placed the order. Make sure you pay attention to market depth and price fluctuations when placing a stop-market order.
Note: The system will perform a margin audit two times: once before you place the order and once before the order is filled. Your stop order may be rejected if your account does not pass the margin audit due to position limits or insufficient margin.