An order can have an acceptable price and still leave part of its requested quantity unfilled. Time in force helps specify what should happen next. Reading that instruction separately from the order type and the eventual execution report prevents an immediate partial fill from being mistaken for a fully completed order.
Follow the evidence
Trace how the event could reach markets, then inspect a competing explanation.
Compare explanations
Switch lenses to see what each account explains—and what remains uncertain.
Suppose an invented order requests 100 units at an acceptable price, while only 40 units are immediately available under the assumed execution conditions. With an illustrative IOC instruction, 40 units can execute and the remaining 60 can be canceled. The result is a partial execution followed by no working remainder. Under the illustrative FOK condition, the requested 100 units must be available for immediate execution in full. If that requirement cannot be satisfied, no portion executes in this simplified example. The distinction concerns the handling of the quantity; neither instruction creates additional liquidity or guarantees that a desired trade will occur. Day and GTC instead describe persistence beyond an immediate attempt. Their operational boundaries still need the venue’s rules: a trading day may have defined sessions, and an advertised GTC policy may include expiration or other conditions. A protocol label is useful terminology, but the customer-facing service must explain what that label means in its actual environment.
Suppose an invented order requests 100 units at an acceptable price, while only 40 units are immediately available under the assumed execution conditions. With an illustrative IOC instruction, 40 units can execute and the remaining 60 can be canceled. The result is a partial execution followed by no working remainder. Under the illustrative FOK condition, the requested 100 units must be available for immediate execution in full. If that requirement cannot be satisfied, no portion executes in this simplified example. The distinction concerns the handling of the quantity; neither instruction creates additional liquidity or guarantees that a desired trade will occur. Day and GTC instead describe persistence beyond an immediate attempt. Their operational boundaries still need the venue’s rules: a trading day may have defined sessions, and an advertised GTC policy may include expiration or other conditions. A protocol label is useful terminology, but the customer-facing service must explain what that label means in its actual environment.
Keep the requested order settings, the broker’s acknowledgment and the execution reports together. Establish whether the intended instruction was accepted before interpreting the fills. A request entered into a form does not, by itself, prove that an order reached the venue with the same parameters. For a completed IOC example, reconcile the executed quantity and the canceled remainder with the requested total. If an order remains working, confirm its current status and expiry conditions from the relevant records. Avoid interpreting an abbreviated status label as proof that nothing executed; a canceled order can already have fills. The worked quantities are hypothetical and do not describe an observed order. The historical FIX references were reviewed on 8 October 2026. Provider support, session definitions and service-specific expiry rules require the provider’s own current documentation.
FIX separates duration from the execution outcome
The official FIX documentation identifies TimeInForce as field 59 and includes Day, Good Till Cancel, Immediate Or Cancel and Fill Or Kill among its values. These instructions concern the order’s persistence or immediate execution requirements. A separate price instruction, such as a limit, answers a different question. FIX Trading Community — TimeInForce, field 59
The FIX Trading Community’s order-state scenarios show an IOC order receiving a partial fill before its remainder is canceled. They also show an FOK order canceled when it cannot be filled immediately in its entirety. The July 2020 document records these protocol scenarios without promising that every venue supports every instruction. FIX Trading Community — Order State Changes, July 2020
The same available quantity can produce different records
Suppose an invented order requests 100 units at an acceptable price, while only 40 units are immediately available under the assumed execution conditions. With an illustrative IOC instruction, 40 units can execute and the remaining 60 can be canceled. The result is a partial execution followed by no working remainder.
Under the illustrative FOK condition, the requested 100 units must be available for immediate execution in full. If that requirement cannot be satisfied, no portion executes in this simplified example. The distinction concerns the handling of the quantity; neither instruction creates additional liquidity or guarantees that a desired trade will occur.
Day and GTC instead describe persistence beyond an immediate attempt. Their operational boundaries still need the venue’s rules: a trading day may have defined sessions, and an advertised GTC policy may include expiration or other conditions. A protocol label is useful terminology, but the customer-facing service must explain what that label means in its actual environment.
Use the accepted instruction and final reports
Keep the requested order settings, the broker’s acknowledgment and the execution reports together. Establish whether the intended instruction was accepted before interpreting the fills. A request entered into a form does not, by itself, prove that an order reached the venue with the same parameters.
For a completed IOC example, reconcile the executed quantity and the canceled remainder with the requested total. If an order remains working, confirm its current status and expiry conditions from the relevant records. Avoid interpreting an abbreviated status label as proof that nothing executed; a canceled order can already have fills.
The worked quantities are hypothetical and do not describe an observed order. The historical FIX references were reviewed on 8 October 2026. Provider support, session definitions and service-specific expiry rules require the provider’s own current documentation.