Time in force: DAY, GTC, IOC, FOK and AON

Who this is for — Anyone who needs to know how long an order can remain active and what happens to unfilled quantity. A limit price sets the worst acceptable price; time in force governs time and the treatment of the remainder.

Time in force (TIF) is the instruction that determines how long an order remains valid. It may also determine whether a partial execution is allowed and whether the remaining quantity stays open or is cancelled. It guarantees neither a fill nor a particular price.

TIF is often associated with a limit order, but supported combinations depend on the system. Some venues accept time qualifiers on protected market orders, stop orders or stop-limit orders; others permit only specific combinations.

Time in force governs time and remainder handling; price, quantity and other instructions remain separate constraints.

The main instructions

Instruction	Duration or constraint	Partial fill	Treatment of remainder
DAY	until the end of the defined trading day or session	normally allowed	cancelled at the applicable expiry
GTC	until cancellation, execution or a system-imposed limit	normally allowed	remains active
IOC	attempts immediate execution	yes	cancelled immediately
FOK	requires the entire quantity immediately	no	the whole order is not executed if the condition is not met
GTD/GTT	until a specified date or time	normally allowed	cancelled at expiry

DAY does not necessarily mean “until 11:59 p.m.” Expiry may coincide with the regular session, an electronic session or a time defined by the broker. FINRA also notes that participation in extended trading hours may require a separate instruction.

GTC does not mean “forever.” A broker may impose a maximum duration; a contract may expire; corporate actions, halts, tick-size changes or risk rules may cause cancellations. Coinbase International, for example, documents a thirty-day limit for GTC and GTT in its FIX specification. That number does not carry over to other venues.

IOC attempts to execute all or part of the quantity immediately at an allowed price. Any quantity that does not find a counterparty is cancelled and does not join the queue.

FOK instead requires the entire quantity to be immediately available at the stated price or better. If that condition is not satisfied, there must be no partial fill.

AON is not FOK

All or none (AON) is a quantity qualifier: the order must be executed in full or not executed. It does not, by itself, require immediacy. FINRA explains that an AON order may remain pending until the full quantity becomes available, the order is cancelled or the applicable expiry is reached; an FOK order must be completed immediately or eliminated.

The distinction can be written compactly:

FOK = complete + immediate
AON = complete, but not necessarily immediate
IOC = immediate, but may be partial

AON is not available on every market or order-entry channel. Priority, visibility and interaction with the book may also differ, so the venue rulebook and broker terms remain controlling.

One order, different outcomes

Assume a buy limit for 10 units at 100, with only 6 units immediately available at 100 or less.

Instruction	Possible outcome on arrival
DAY or GTC	6 units execute and 4 remain in the book, if the venue permits a partial fill
IOC	6 units execute and 4 are cancelled
FOK	no execution because all 10 units are not immediately available
AON	no partial execution; the order may wait for the full quantity if supported

This is a teaching model, not a fill prediction. The book can change before the order arrives; pre-trade controls, queue priority, self-trade prevention or risk limits may produce a rejection or a different result. See Order priority and partial fills.

Venue and broker dependence

Identical abbreviations do not imply identical implementations. CME lists DAY, GTC, GTD, GFS, Fill and Kill and Fill or Kill among its available choices. Coinbase Exchange documents GTC, GTD/GTT, IOC and FOK, and makes post-only incompatible with IOC and FOK. A broker may expose only a subset, translate the labels in its interface or impose its own expiry.

At minimum, an operator should verify:

which session ends a DAY order;
the effective maximum life of a GTC order;
whether IOC accepts a minimum quantity;
which price and quantity are tested for FOK;
whether AON is available and how it is prioritised;
behaviour during auctions, halts and extended hours;
the status returned after rejection, expiry or cancellation.

TIF is also distinct from post-only. The former governs duration and residual quantity; the latter governs the order's initial interaction with liquidity. A platform may allow GTC post-only while prohibiting IOC post-only.

Reading order states

An accepted order has not necessarily executed. Logs should distinguish receipt, acceptance, opening, partial fill, complete fill, cancellation, expiry and rejection. Order lifecycle reconstructs those stages.

To compare instructions, retain the order identifier, submitted TIF, timestamps, original quantity, executed quantity and reason for the remainder. The label “cancelled” alone does not reveal whether cancellation resulted from IOC, DAY expiry, user action or a venue control.