An order in a security that initiates an automatic execution immediately upon entry into an exchange system/ order book. Auto-ex orders are filled only against securities in the same venue, and hence execute solely against the quotes/ orders of the venue participants (subject to automatic execution functionality of the venue that does not involve charging a separate quote-access fee).

Auto-ex orders are cancellable before trade initiates through the quote or order of a participant that is not eligible to receive such orders or if the orders would lock or cross such a quote or order.