Day Order
A day order is a buy or sell instruction that expires automatically at the end of the regular trading session on the day it is entered, if it has not been executed by that time.
A day order is the default order duration for virtually all equity trades placed on U.S. exchanges and electronic trading platforms. If you place a limit order to buy 100 shares at $45 and the stock never trades down to $45 during that session, the order is cancelled without execution at the close of regular market hours — typically 4:00 PM Eastern Time for NYSE and Nasdaq-listed securities.
The day order convention exists to prevent accumulation of stale orders in the market. Markets are dynamic: prices, news, and investor circumstances change constantly. An order that made sense at 9:30 AM may be undesirable by 3:30 PM, and one that was not filled may be irrelevant the following morning. By automatically expiring unfilled orders, the day order system keeps order books cleaner and reduces the risk of unintended executions.
Day orders apply to limit orders, stop orders, and most other order types except those that are explicitly designated as good-till-cancelled (GTC) or an alternative duration. Market orders, by their nature, are almost always filled immediately and rarely need a duration qualifier, though they are technically day orders as well.
Investors who actively monitor their portfolios during trading hours often prefer day orders because they maintain full control: each day they can reassess the market and decide whether to re-enter the order at the same or a different price. This contrasts with GTC orders, which require active cancellation if the investor's view changes.
It is worth noting that extended-hours trading sessions — pre-market and after-hours — may have separate rules. Orders designated for extended-hours sessions typically still expire at the end of that session. Investors should check with their broker whether day orders placed during extended hours also participate in regular-hours trading or are confined to the extended session. FINRA and SEC oversight extends to order handling practices across all sessions, and broker-dealers must maintain accurate records of order placements, modifications, and cancellations.