{
  "id": "UBL-SR-53",
  "country": "EU",
  "syntax": "ubl",
  "group": "syntax",
  "severity": "fatal",
  "severity_note": "fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.",
  "spec": "Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL",
  "statement": "CompanyID (VAT Identifier) must be stated when providing the PartyTaxScheme/TaxScheme/ID.",
  "statement_lang": "en",
  "context": "cac:PartyTaxScheme",
  "test": "exists(cac:TaxScheme/cbc:ID) and exists(cbc:CompanyID)",
  "meaning": "The company identifier must be stated when a party tax scheme identifier is present. The statement ends with a period and says must. It does not say shall. It is 89 characters. The flag is fatal. The context is a party tax scheme. The published test calls exists for the tax scheme identifier and for the company identifier. It does not call count and it does not use <=.",
  "fix": "Send the company identifier when the tax scheme identifier is present.",
  "example_fail": "A party tax scheme names a tax scheme identifier and omits the company identifier.",
  "example_pass": "A party tax scheme names both a tax scheme identifier and a company identifier.",
  "example_note": "Illustration of the condition in the official statement. Not an example published by the source.",
  "source_url": "https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/UBL-SR-53/",
  "source_retrieved": "2026-10-18",
  "last_verified": "2026-10-18"
}