All parties to the transactions must be financial institutions.
If the Sender wishes to instruct the Receiver to debit its account serviced by the Receiver and to credit one of its several accounts at an institution specified in field 57a, field 58A in the related sequence must contain the number of the account to be credited and the name of the Sender.
If the Sender wishes to instruct the Receiver that funds are to be moved between two accounts owned by the Sender and serviced by the Receiver, field 53B must specify the number of the account to be debited and field 58A, in the sequence relating to this order, must specify the number of the account to be credited and the name of the Sender.
Each transfer of funds between the ordering institution and a beneficiary institution is always related to another transaction. Field 21 must refer to this transaction.