The UID is composed of 9 numbers, is randomly generated and contains no information about the enterprise (anonymous identifier). The Swiss origin of the number is indicated by the "CHE" prefix, which is the three-letter country code of the ISO 3166-1 standard. The last number refers to the check digit (C) determined by the Modulo 11 standard calculation method.
To make it easier to read, the prefix is separated from the numerical part by a dash. The numerical part of the UID is divided into three blocks of three numbers separated by a full stop:
On letterheads, invoices, receipts or other printed matter, the UID suffix is used to indicate whether a UID unit is registered in the commercial register or whether it is subject to value added tax. This suffix is not an integral part of the UID as a unit's situation may change over time with regard to being registered in the commercial register or being subject to VAT. The number stays the same, only the suffix can change.
If a UID entity is registered in the commercial register, its UID is completed with the suffix "RC", as in the example:
If a UID entity is registered in the VAT register, its UID is completed with the suffix "TVA", as in the example:
If a UID entity is registered in both the commercial and VAT register, both suffixes are added to the UID and separated by a slash:
The RC suffix is always indicated first. If a UID entity is removed from a register, the relevant suffix is also removed.
The UID register provides the suffixes as additional information. They can be indicated in French, German or Italian. The keeping of suffixes by the UID services is optional. The use of the UID suffix by the UID entities is also optional unless specifically required by legal provisions (e.g. when the UID is used as a VAT number).