The possible order types for an equity order are:

• Buy: A buy order is an order to acquire an equity.
• Sell: A sell order is an order to liquidate an equity.
• Buy to close: A buy to close order is an order to buy back a previously opened short sale position. It can only be conducted in a margin short account.
• Short sell order: A short sell order is an order to sell borrowed securities in anticipation of a price decline and is required to return an equal number of shares at some point in the future. It can only be conducted in a margin short account.