The term At-the-Close refers to broker instructions to buy or sell securities at the very end of the trading day. If an At-the-Close order cannot be executed in the final minutes of trading, then it will be canceled.
At-the-Close instructions typically involve market or limit orders to buy or sell stocks. When placed, an At-the-Close order must be executed in the closing few minutes of a trading day. If the entire order, or any portion of it, cannot be executed before the closing bell, then it is automatically canceled. It is possible for an At-the-Close order to be partially filled.
If combined with a market order, a trader is trying to buy or sell a security at a value near the security's closing price. How near the order's value is to the closing price will depend on factors such as the market's liquidity for the security being traded. By placing an At-the-Close order, the trader does not have to worry about executing a market order later in the day.
Traders that believe a security will move significantly up or down near the end of the day, and are looking for a specific price point, have the option of combining At-the-Close instructions with a limit order. If the price of the security does not pass through the limit price, then the order is not executed.
All-or-None, Fill-or-Kill, Good-Til-Canceled, Immediate-or-Cancel, National Best Offer, National Best Bid, market order, limit order, day order, One-Triggers-the-Other, One-Cancels-All, Good-Til-Date, At-the-Opening, Market-on Open, Market-on-Close, Time-in-Force, Market-if-Touched, Trailing If-Touched