246. The underlying should be identified by using a unique identification for this underlying based on its type. Fields 2.13-2.18 describe the underlying, and the field 'Underlying identification type' in particular indicates that the underlying is either a basket, index or asset identified with an ISIN.

247. In the case of derivatives on indices, the counterparties should report the ISIN of the underlying index, if available, rather than the ISIN of the derivative. In addition, under the RTS on reporting the counterparties should report the standardised code indicating the index (if available) as well as the name of the index which should always be populated.

248. In the case of credit derivatives, field 'Underlying identification' should be reported in case of Credit Default Swap (CDS) based on specific reference obligation. For CDS hedging against the default of an entity, such entity should be reported in the 'Reference entity' field.