The order mass cancel request message requests the cancelation of all of the remaining quantity of a group of orders matching criteria specified within the request. NOTE: This message can only be used to cancel order messages (reduce the full quantity).
An order mass cancel request is assigned a ClOrdID <11> and is treated as a separate entity. The order mass cancel request is acknowledged using an Order Mass Cancel Report. The Order Mass Cancel Report will contain the ClOrdID <11> that was specified on the Order Mass Cancel Request. The ClOrdID <11> assigned to the cancel request must be unique amongst the ClOrdID <11> assigned to regular orders, replacement orders, cancel requests, and order mass cancel requests.
An immediate response to this message is required. It is recommended that an ExecutionRpt with ExecType <150>=Pending Cancel be sent unless the Order Mass Cancel Request can be immediately accepted (ExecutionRpt with ExecType <150>=Canceled) or rejected (Order Cancel Reject <3> message).
Specifying order cancellation criteria is specified using the MassCancelRequestType <530> field: