The type of order instructing the execution of the entire order quantity at the stated price (or better), or none of it. This prevents partially filled orders. The difference between All-or-None and Fill-or-Kill is that the AON order is left open if the entire order quantity cannot be filled, whereas the FOK order will be cancelled.

All or none or AON is, in investment banking or securities transactions, "an order to buy or sell a stock that must be executed in its entirety, or not executed at all".