Validity instructions

PrepNuggets

Traders specify when an order should be executed. Most orders are day orders, meaning they expire if unfilled by the end of the trading day. 

Good til canceled orders last until they are filled or when the trader cancels the order. 

Immediate-or-cancel orders are canceled unless they can be filled immediately.

Good-on-close orders are only filled at the end of the trading day. If they are market orders, they are referred to as market-on-close orders. These are often used by mutual funds because their portfolios are valued using closing prices. There are also good-on-open orders, though not as common.

See also: Stop order