A conditional time-in-force order known as “fill or kill” (FOK) is used to trade stocks, currencies, metals, and energy. A broker is required to either execute the full order or cancel it right away when a trader or investor uses this kind of order. It is forbidden to open or partially close a position on a FOK order. Only the specified volume may be used to execute the order. An immediate-or-cancel order (IOC) and an all-or-none (AON) are combined in a FOK.