🎯 Orders·advanced

Fill or Kill (FOK)

Also called: fok

An order that must fill IMMEDIATELY in full or be cancelled entirely — no partial fills allowed.

Fill or Kill (FOK) is an aggressive time-in-force instruction that says: "Fill my entire order right now at my specified price or better, or cancel it completely." There are no partial fills — if the broker can't fill the full size at the specified price, the order is killed. FOK is used by institutional traders who need certainty. If a fund needs to buy exactly 50 standard lots of EUR/USD at 1.0950 and any partial fill would mess up their hedging, they use FOK. The order either fills as a unit or doesn't fill at all. For retail traders, FOK is rarely useful. Retail size is usually small enough that partial fills aren't a problem. The exception is during news events when liquidity is thin — FOK lets you avoid getting filled at terrible prices in fragments.

Real trade example

Bank desks running interbank FX use FOK constantly to manage their exposure on big tickets. Retail platforms rarely see FOK orders because the size differential makes them unnecessary.

Related terms

Immediate or Cancel (IOC)

advanced

An order that fills as much as possible immediately, then cancels the unfilled portion — no resting orders.

Good Till Cancelled (GTC)

beginner

An order that stays active until you manually cancel it or it fills — used for set-and-forget pending orders.

Limit Order

beginner

An order to buy or sell at a specific price or better — guarantees price, not execution.

Market Order

beginner

An order to buy or sell immediately at the current market price — instant execution, no waiting.

Stop-Limit Order

intermediate

A combination order that triggers like a stop but fills like a limit — protects against bad fills during fast markets.

Trailing Stop

intermediate

A stop loss that automatically moves in your favor as price moves — locks in profit while letting winners run.

← Back to glossary Ask the desk a follow-up →