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Order Types
What Is a Fill-or-Kill Order? (And AON, IOC)
A family of order qualifiers most retail traders never touch — but they explain how large or all-or-nothing orders behave.
NoVo Options Trading · 2026
Fill-or-kill (FOK), all-or-none (AON), and immediate-or-cancel (IOC) are order qualifiers that control whether an order must fill completely, immediately, or be canceled. They matter mostly for larger or size-sensitive orders.
What each does
Fill-or-kill: the entire order must fill immediately and completely, or it’s canceled — no partial fills, no waiting. All-or-none: the order must fill completely (all contracts) but can wait — it won’t partially fill. Immediate-or-cancel: fill whatever you can right now, cancel the rest — partials allowed, no resting.
Why they exist
They protect traders placing larger orders from awkward partial fills. If you want 50 contracts and a partial 12-lot would leave you mis-hedged or over the liquidity, AON or FOK ensures you either get all of it or none. For most retail scalpers trading a few liquid contracts, these rarely matter — a normal limit fills fine.
These qualifiers are about completeness and immediacy of the fill — useful for size, mostly irrelevant when you’re trading a handful of liquid contracts.
The takeaway
FOK/AON/IOC are niche qualifiers for controlling partial fills on larger orders — good to recognize, rarely needed for small scalps. As your size grows relative to a strike’s liquidity, they become more relevant. For typical retail 0DTE, a standard limit does the job.
More on this: IOC, FOK, and AON: The Options Order Types Nobody Explains · Marketable vs Non-Marketable Orders, Explained
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NoVo is a software tool for market analysis and for executing trades you initiate, not financial advice. This article is general education, not investment advice. Options trading involves substantial risk of loss, up to and including your entire capital. NoVo makes no guarantee of profit, win rate, or performance, and past results do not predict future outcomes. You are responsible for your own broker account, configuration, and trading decisions.