Mandatory
This field specifies the related reference.
This field must not start or end with a slash '/' and must not contain two consecutive slashes '//' (Error code(s): T26).
This field contains the reference number assigned by the Receiver to the related securities loan, eg, the contents of field 20 Transaction Reference Number of the MT 516 Securities Loan Confirmation received or the contents of field 20 Transaction Reference Number of the previous MT 581 received.
If the Receiver's reference is not known, NONREF must be used in this field.