The CRO field is filled in when the transfer is in favour of the same institution as the ordering bank, while the TRN field is filled in when the transaction is between different banks. Specifically, the assignment logic is as follows:

• the CRO is assigned to a credit transfer executed on the same bank
• the TRN is assigned to a credit transfer executed within the cut-off time on another bank
• the CRO at the time of entry is assigned to a booked credit transfer, in favour of the same bank or another institution; when executed the CRO remains if in favour of the same bank, it becomes TRN if credited to another institution.