US citizens living in Switzerland are generally denied retirement funds. 
Excluded are: US persons according to the FATCA agreement with USA. US Persons: US citizens, USA birthplace or a US territory (Marianen, Guam, Puerto Rico the American Virgin Islands) 
The VZ website is not intended for users who are subject to a jurisdiction that prohibits publication of and/or access to the VZ website due to nationality, residence/registered office... This specifically applies to users who are nationals of or reside in the USA (so-called US persons). 
The investment products of QUANTUS are not offered, sold or delivered in the USA or to US individuals (as defined in Regulation S of the Law). The information on this website constitutes neither an offer nor a solicitation in the USA or to US citizens to invest in investment products of QUANTUS.