What do AON, OPG, and CLO mean?
These are available order qualifiers you can elect to attach to your stock orders; they are listed under “Instructions” on the order entry page.
AON - AON orders are qualified as All-or-None. A buy or sell order can be marked AON to signify that no partial transaction is to be executed. This type of instruction can only be used for orders greater than 100 shares, and cannot be used for NYSE listed symbols.
OPG – OPG orders are qualified as At-the-Open, also referred to as Market-on-Open (MOO). An OPG qualifier requests that your order will be executed at the official opening price of the primary listing exchange. The order will be accepted if it is received before 9:15AM (ET). The order can be cancelled after 9:15AM, but it cannot be edited. After 9:28AM, OPG orders cannot be edited or cancelled. Any unfilled orders after the opening will be cancelled.
CLO - CLO orders are qualified as At-the-Close, also referred to as Market-on-Close (MOC). A CLO qualifier requests that your order will be executed as close to the closing price as possible. The order will be accepted if it is placed before 3:40PM (ET) . CLO orders cannot be edited or cancelled after 3:45PM (ET). Any unfilled orders after closing of the market will be cancelled.