Identifying Systems are consistent and unique identifiers that can relate to corporate legal entities, or more specifically aspects of their activities, or registration with an official register, e.g a tax numbers refers to a legal entity's registration with a tax office, charity numbers refer to an entity's registration with the body that authorises charities.
It's worth noting that such registrations (and hence the identifiers) are in general subtly separate from the entity itself, having their own attributes, associations and even lifespan. For example, an entity can be removed from a Charity Register but still carry on trading, albeit without the tax benefits of charitable status. Similarly, in some countries an entity may have more than one tax numbers over a period of time, or may use its parent's tax number.
There are many such identifying systems, and only those OpenCorporates has data for are listed below. If you know of other identifying systems you think we could usefully import, please let us know
