A day order is a trading instruction that remains active only during the current trading session and automatically expires if not executed by the market close. This order type prevents trades from executing at potentially unfavorable prices during after-hours trading or the next day’s opening session. Day orders provide traders with precise control over order timing and execution windows.

Day orders are the default order duration for most trading platforms and are particularly useful for active traders who monitor positions closely. Unlike Good-Till-Canceled (GTC) orders that remain active until executed or manually canceled, day orders eliminate the risk of forgotten orders executing at inappropriate times. This order type is essential for intraday trading strategies.

Real-world example: A day trader places a day order to buy 500 shares of Microsoft at $330, knowing the order will automatically cancel at 4 PM if not filled, preventing execution during volatile after-hours trading.