KEY POINTS
  • The wealthy are building "passport portfolios" — collections of second, and even third or fourth, citizenships — in case they need to flee their home country.
  • Recent high-profile examples of second citizenships include billionaire tech investor Peter Thiel, who added a citizenship in New Zealand, and former Google CEO Eric Schmidt, who applied for citizenship in Cyprus.
  • The top destinations for supplemental passports among Americans are Portugal, Malta, Greece and Italy, according to Henley & Partners.

A version of this article first appeared in CNBC's Inside Wealth newsletter with Robert Frank, a weekly guide to the high-net-worth investor and consumer. Sign up to receive future editions, straight to your inbox.

Wealthy U.S. families are increasingly applying for second citizenships and national residences as a way to hedge their financial risk, according to a leading law firm.