A time-in-force order that requires filling promptly or entirely, or being canceled, is known as a fill or kill (FOK) order. They cannot, however, be partially filled; they must be filled at the limit price or better.
It shares characteristics with all or nothing (AON) orders frequently employed in stock trading. The only key distinction between the two orders is that an AON order does not have a time focus, whereas a FOK order concentrates on whether or not the order will be filled immediately.
Day traders who want to scalp or profit from modest price variations over a brief period typically employ FOK.
Additionally, traders employ them to prevent orders from being partially filled. When one FOK order is executed, a trader may issue many FOK orders at once and cancel the others.
In reality, the fill-or-kill (FOK) type of trade does not happen very frequently. Other ways of instructing a brokerage on the time frame in which a trade is to be executed include good ’til canceled (GTC), which keeps an order open until it can be filled at a specific price, and immediate or cancel (IOC), which means to fill all or part of the order instantly, then cancel any part that cannot be filled.
