Route: Sources & references
Sources & references
This site is an educational reference. It is written using publicly available information from official and institutional sources. Links below are provided for transparency. Access dates reflect when they were last checked for this site.
European Commission
- Tax Identification Numbers (TIN) portal (accessed 2026-01-19)
OECD
- Tax Identification Numbers guidance and country information (accessed 2026-01-19)
National administrations
Tax identifiers are defined by each country. For country-specific formats and rules, consult the relevant national tax administration.