The two states had signed the protocol on 23 September 2009 in order to revise their 1996 DTA. Ratified in 2010 by the Federal Assembly, the protocol was blocked in the US Senate, which gave its final approval on 17 July 2019, almost ten years later.

The exchange of information between the two states is the core element of the revision. There is no longer any distinction between tax evasion and tax fraud for both individual and group requests. The revision is now in line with the international standard on the exchange of information upon request, already applied by Switzerland to more than 100 states.

Requests can be made on or after the protocol has entered into force, i.e. from 20 September 2019. Requests in relation to financial accounts must relate to cases which have occurred since 23 September 2009, i.e. the date of signature of the protocol of amendment. Requests based on the FATCA agreement are still admissible for cases from 30 June 2014. It is anticipated that a large number of requests will be filed by both states in the next few months.

The protocol's entry into force paves the way for a further revision of the double taxation agreement which was signed back in 1996 and might need an update.