Mandatory in a conditional sequence (C4)
This field contains the identification of the individual allocation.
This field must not start or end with a slash '/' and must not contain two consecutive slashes '//' (Error code(s): T26).
If the message is an amendment to individual allocations, ie, field 22A in sequence A is AMNA, in a previously sent MT 303, this field must contain the same values as the original allocations which have to be amended.