# Organization identifiers Normally, publishers collect *legal identifiers* from the organizations that are part of the contracting process. [Organization identifiers](../../schema/identifiers.md#organization-ids) can be provided in OCDS by identifying the **organization registers** used in the source data, choosing an appropriate **organization register prefix** for each one, and identifying the organizational ID for each registry or list and organization in the data. Use [org-id.guide](http://org-id.guide) to find the code for the register your identifiers are drawn from. If no code exists for the register, contact the [Data Support Team](../../support/index) to register an organization list. If a publisher chooses not to register an organization list with org-id.guide, the publisher ought to describe the organization list in a [publication policy](../publish.md#finalize-your-publication-policy), and needs to ensure that its prefix doesn't collide with a list code in org-id.guide. ## Worked example The Government of the UK uses identifiers from [Companies House](https://www.gov.uk/government/organisations/companies-house) to uniquely identify suppliers. Companies House has an entry in [org-id.guide](http://org-id.guide/list/GB-COH), which specifies the "GB-COH" code for the registry. IBM has been assigned the company number ‘04336774’ by Companies House. The globally unique organization identifier for IBM can then be expressed as in the `identifier` section in the sample below: ```{jsoninclude} ../../examples/organizations/identifiers.json :jsonpointer: /releases/0/parties/1 :expand: identifier, additionalIdentifiers ``` The publisher also collects an extra identifier, which is disclosed in the `additionalIdentifiers` block. The extra identifier is the VAT identification number for suppliers. Note that the VAT registry is not present in org-id.guide, but the publisher followed the instructions in the [org-id meta-data guide](http://docs.org-id.guide/en/latest/metadata/#assigning-a-code) to build the "GB-VAT" code used in the `scheme` field: the two-letter country prefix ("GB") plus a short abbreviation for the registry ("VAT"). The publisher checked that it does not conflict with any list code in org-id.guide.