The federal law on business identification number has changed with effect from 1 Jan 2014. The old registration number format was 8 characters but the new format supports 19-20 characters.
The current VAT number validation format is CH + 6 digits (the six
digits after the prefix should be numeric). Example: CH123456. Swiss companies
can continue to use the current VAT number format until the end of 2013.
Effective from January 2014, there are changes in the validation of Tax
Registration Number. The new VAT number validation is formatted as CHE + nine
numeric positions + extension. Example: CHE-123.456.789 MWST.
The following validation is implemented.
The total length of the new VAT number, therefore, can be 19 or 20
a) Apply Patch 15964400 as detailed in Doc ID 1521534.1 - New Swiss (CHE) Tax Registration Number
b) Enter/update existing tax registration number as
per new format before January 2014 to avoid any user interface, reporting or
data issue. The tax registration number as per old format will not be valid
effective from January 2014.
You can enter the registration number using multiple
navigations but the most common interface is: Tax Manager > Parties: Party Tax Profiles > Tax Registrations
For full details on this change in legislation, please review the Federal Administration website.