Create a Market-On-Close Order
An MOC (market-on-close) order will execute as a market order as close to the closing price as possible.
To create an MOC order
Click the Ask price to create a BUY order, or the Bid price to create a SELL order.
In the Type field, select MOC as the order type.
To transmit the order, click the "T" in the Status field.
For a more detailed description of MOC orders, visit the Order Types information page.