The US is currently the second most important trade partner of Switzerland and the most important investment location for Swiss companies. Moreover, offices of American companies located in Switzerland contribute considerably to Swiss prosperity1. This is one of the reasons why, according to the statistics on foreigners of the Federal Office of Migration, 17,648 US citizens (other than dual citizens) were permanent residents of Switzerland as of November 20152. It is estimated that around 100,000 Swiss-American dual citizens live in Switzerland. At the same time, most Swiss citizens who live outside of Europe reside in the US. The number of Swiss citizens living in the US amounted to 78,696 as of the end of 20143.
In the context of Swiss-American succession, US tax and succession law must be considered in addition to Swiss law. This arises, for example, when counseling American citizens with residence in Switzerland or Swiss citizens who own US real estate or US securities. There is a considerable potential for conflict when it comes to succession planning because the Swiss and US succession and tax laws are organized differently and are not compatible in all aspects. In international succession matters between the US and Switzerland it is also important to consider the Swiss-American treaty of friendship, commerce and extradition of 25 November 1850 (subsequently "Treaty")4. Articles V and VI of the Treaty which address conflict of law issues are particularly significant.
Before dealing in detail with the handling of Swiss-American estates, the principles of US matrimonial property and succession law must be examined in order to understand the problems arising in connection with such estates. Specific references to US law refer to the state of New York.
II Principles of US Matrimonial Property and Succession Law
There is no uniform US matrimonial property and succession law. Each of the 50 federal states has its own conflict of law rules and substantive matrimonial property and succession law. Attempts to comprehensively harmonize the private law of the federal states by way of Model Laws such as the Restatements5 and the Uniform Probate Code, which were recommended to the individual states for adoption and for the transformation of their legislation, have remained widely unsuccessful. The Restatements have influenced the succession laws of certain states and some states have at least adopted parts of the Uniform...