Fill or Kill (FOK) is a type of order used in financial trading that requires the entire order to be executed immediately, or canceled (killed) if it cannot be filled immediately. FOK orders are often used by traders who want to ensure that they receive the full quantity of their desired trade at the price they specified, and do not want to risk partial fills or delayed execution.
FOK orders are commonly used in fast-moving markets or for large orders where the trader wants to minimize the risk of slippage, which occurs when the execution price of an order differs from the expected price. By requiring immediate execution or cancellation, FOK orders help traders to manage their risk and ensure that they receive the desired price and quantity for their trade.