Basics

Fill-or-Kill (FOK)

By Ryan Silk & Lawrence Polatchek · Reviewed April 2026 · Options Trading Glossary

Execute entire order immediately or cancel

What is Fill-or-Kill (FOK)?

Fill-or-Kill (FOK) An order that must be executed immediately in its entirety or canceled completely. No partial fills are allowed. Useful for multi-leg option strategies where you need all legs filled together at your desired price.

Complete Definition

An order that must be executed immediately in its entirety or canceled completely. No partial fills are allowed. Useful for multi-leg option strategies where you need all legs filled together at your desired price.

Related Terms

All Or None Good Til Canceled Limit Order

Written by

ApexVol Research Team

Quantitative options research

All calculations use live ORATS institutional data — the same source used by professional volatility desks.

Technical reviewer

Ryan Silk, ApexVol Founder

Reviewed for technical accuracy

10+ years trading options. Built ApexVol's pricing engine, Greeks model, and IV-rank methodology.

This guide is updated as market conditions and ORATS data change. Last revised 2026-05-12. How we research →

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