OMTax is the cantons' joint web solution for collecting supplementary tax. The application was developed and is operated by the Swiss Tax Conference on behalf of the cantons.

The following pages provide you as a company with information and services relating to the joint OMTax web solution.

In a protected area, employees of the OMTax support organisation of the federal and cantonal tax administrations have access to the business organisation documents, the test and training documents, the user administration and the Jira service desk tool for error management.

The OMTax application will be available in the ePortal at www.omtax.admin.ch from 2 January 2025. From that date, the taxable business units of large corporate groups can register in OMTax and make their declaration for the supplementary tax.