# ibr-sr-57

Source: https://xmlvalid.com/rules/ibr-sr-57

> Company identifier MUST exist in the party tax scheme class.

- Level: error
- Rule sets: PINT Billing rules 1.1.3, PINT Billing rules (as shipped with PINT AE) 1.0.4
- Context: `//cac:PartyTaxScheme`
- Test: `exists(cbc:CompanyID)`

Validate a document against these rules: https://xmlvalid.com/validate