ISO 6523 ICD (International Code Designator)

The ICD is an ISO 6523 code that states which registry an organisation identifier comes from.

Definition

The ISO/IEC 6523 standard defines a structure for identifying organisations unambiguously. It introduces the ICD (International Code Designator), a code that designates the identification scheme — that is, the registry or authority — an identifier belongs to.

A complete identifier therefore reads in two parts: the ICD (which registry) and the identifier itself (the value within that registry).

Role

Without the ICD, the same number could be interpreted in several ways. The ICD resolves this ambiguity by stating the source:

• a national legal company number (for example a SIRET) falls under a given ICD;
• a DUNS number, a GS1 GLN or a VAT number each fall under a distinct ICD.

So the ICD + identifier pair is globally unique and interpretable without knowing the issuing context.

Good to know

The ICD is central to the e-invoicing ecosystem. In the PEPPOL network and in the EN 16931 standard, party identifiers are qualified by a scheme often based on ISO 6523 ICD values.

ICD codes are published and maintained by a registration authority, which keeps them stable over time.