By virtue of Article 12 of the FATCA agreement (most-favoured-nation clause; hereinafter referred to as the "MFN clause"), Switzerland is entitled to equal treatment if the United States agrees on more favourable terms with another partner jurisdiction. The MFN clause states that the United States has to notify Switzerland of any such more favourable terms and apply them automatically as if they were specified in the FATCA agreement, effective as at the date of the entry into force of the FATCA agreement with the other partner jurisdiction.
The United States notified Switzerland about the application of the MFN clause for the first time in a letter dated 27 March 2015 (hereinafter referred to as the "MFN letter"). This was triggered by the FATCA agreement entered into with Bermuda, which came into force on 19 August 2014. The amendments to the agreement and Annex I have been published in the national languages in the Classified Compilation of Federal Legislation. The amended English version is also available.
In order to coordinate the retroactive application of the amendments notified by means of the MFN letter, Switzerland and the United States signed a mutual agreement in Bern on 28 July 2015: