When Do Traders Need Fill or Kill Orders?

Community Submission - Author: John Ma

Many trading platforms offer a specialized order type called “Fill or Kill” (FOK) that serves a specific purpose: execute the entire order immediately, or don’t execute it at all. This all-or-nothing approach prevents traders from getting stuck with partial fills they don’t want.

At first glance, FOK sounds similar to “All or Nothing” (AON) orders—and it should, since both require complete execution or no execution. The key difference? AON doesn’t care about timing. FOK demands instant execution. This matters when you’re racing against the clock and can’t afford to wait around for gradual fills.

Why would a trader choose FOK over regular orders?

Picture this: you’re an altcoin enthusiast ready to launch a masternode, which requires holding exactly 1,000 units of a specific cryptocurrency. Time is tight—you need those coins now, not days from now. Instead of placing one large buy order on a single exchange and hoping for the best, you could simultaneously place multiple Fill or Kill orders across different markets, each requesting 1,000 units.

Here’s the beauty of FOK: you only get charged if you secure the full 1,000 units. If an order gets even one unit short, it’s automatically rejected—no partial purchase. Once one exchange fills your 1,000-unit FOK order completely, you instantly cancel all your other pending orders on rival platforms. You avoid overpaying for coins across multiple venues and skip the hassle of managing partial positions.

This makes FOK orders particularly valuable for traders who need all-or-nothing certainty and can’t afford delays or leftover fractions of their intended purchase.