Hi all, could someone explain the difference between tags CustOrderCapacity (582) and OrderCapacity (528)? Thank you.
Similar to CustOrderHandlingInst(1031) and DeskOrderHandlingInst(1035). I believe it is for cases where you have a client (customer) sending an order to a broker who sends it to a venue for execution. It allows you to specify the order capacity (or order handling instruction) of both the client and the broker in the same message, i.e. the message from the broker to the venue.
These two fields serve two different purposes despite similar sounding names. OrderCapacity(528) is typically used in-conjunction with OrderRestrictions(529). These two fields are a replacement to the old FIX 4.2 Rule80A(47) field. Rule 80A is a US specific rule, given that the name was too specific to US market, FIX 4.3 changed that to be generic OrderCapacity and OrderRestrictions. OrderCapacity is the capacity of the order submitter when they send in that order.
CustOrderCapacity historically is used by listed derivatives initially. There is a regulatory angle to this field in that the CFTC requires this information to state the type of customer who originated the order.