TIN Check Switzerland
The OASI (Old Age and Survivors Insurance Number) consists of 13 digits (format: 756.9999.9999.99). The first 3 digits correspond to an initial country code that is “756” for Switzerland.
The TIN is called the UID-number (Unternehmens-Identifikationsnummer) and is centralized at a federal level. The TIN consists of 9 digits with the prefix CHE (format: CHE-999.999.999).