IOC, day, GTC, and other common order instructions

Order instructions tell the market how long an order should remain active or how it should behave if it cannot be filled at once. In options, these instructions matter because they shape exposure, speed, and price control in changing liquidity conditions.

Common order instructions define how an order is handled once it is sent to the market. IOC, or immediate-or-cancel, means the order should execute at once in whole or part and any remainder is cancelled. A day order remains active for the trading day unless filled or cancelled, while a GTC order generally remains working beyond the day until it is filled, cancelled, or expires under the broker’s rules. In the article, IOC is highlighted as useful when you want a quick liquidity test without leaving an order exposed for long. More broadly, these instructions matter because time in force is part of liquidity management: it affects whether you are probing the market briefly or leaving an order resting as conditions change.

• Trading 101: Basic Order Types investor bulletin
• Order Types
• Futures Order Types