Fill or Kill (FOK)
The Fill or Kill Order or simply FOK, is an order type that some exchanges and trading platforms offer. This order type pertains to the concept that orders must be filled wholly or not executed at all.
Fill or Kill is pretty much like the All or Nothing Order (AON) in that the order should be filled fully or definitely not at all. The fundamental difference between the two is that the AON order doesn’t focus in a specific point in time.
The FOK is usually used when a trader opts to not accept partial asset delivery. One such example is when these have a time-based demand to fill their orders within the context of market or exchanges that are specific and unlinked. What an FOK order type ultimately does is allow traders to create a number of orders and wait for one that could be executed without being compelled to take the risk of receiving partial fills. Traders are only able to cancel the remaining orders once one of these orders is filled effectively.