Instructions to an agent or broker to buy or sell a security at the price obtainable at the time the trading opens, otherwise to cancel the order.It is an at the opening order is a way for an investor to secure a position at the opening of a trading session.A trader can place a market at the opening order or a limit at the opening order. A market at the opening order is an order to buy or sell a specific number of shares at the best price available at the opening of the market session, regardless of what that price might be.An order specifying that a trade is to be executed at the opening of the market, otherwise it’s canceled. limit at the opening order specifies the price that the investor will accept. If the specified price is not available, then the limit at the opening order is canceled. An at the opening order is often employed if an investor anticipates a large price movement during the session and wishes to get in early.
With this type of order you are not necessarily guaranteed the opening price.