All or None (AON)
An order that must fill completely or not at all, but unlike FOK it can wait for a full match.
All or None (AON) requires the complete order quantity to be filled before any execution occurs. Unlike FOK, it does not demand immediate execution — it can remain in the book waiting for the full size to become available.
AON orders are not displayed in the public order book and may never fill if the required size is never available at the limit price.
Use AON when transaction costs or lot-size requirements make a partial fill economically unworkable.