Optional
This field identifies the financial instrument.
At least Identification of a Security (Subfield 1) or Description of Security (Subfield 2) must be present; both may be present (Error code(s): T17).
ISIN is used at the beginning of Identification of Security (Subfield 1) and must be composed of uppercase letters only (Error code(s): T12).
When a non-ISIN identifier is used, one of the following codes must be used in Narrative:
Either the ISIN identifier or a non-ISIN identifier, or both, must be used.
It is strongly recommended that the ISIN be used.