Along with stock and real estate portfolios, the global rich are now buying a new form of economic security: passport portfolios.

Wealthy investors from around the world are increasingly shopping for visas or citizenship in other countries, hoping for a personal hedge against their own volatile governments or economies. A vast majority are new millionaires and billionaires from emerging-market countries, especially China, Russia and nations in the Middle East. Often, they’re shopping for passports or entree into Europe, the United States, Canada and Australia.

Experts estimate that these “economic citizens” are spending $2 billion a year on second or third passports and visas. Demand is so strong that governments around the world have started an arms race of sorts for V.I.P. visas, offering ever-faster residencies and passports for ever-higher prices. Over the past year, Australia, Canada, Britain and several other European countries have raised the prices or investment requirements of their so-called golden visas and created a new fast lane for citizenship.

“Wealthy people in fragile countries want to have a second option in a more stable country,” said Christian H. Kalin, group chairman of Henley & Partners, a citizenship advisory firm based in London. “The wealthy already diversify their assets for protection. Now they want to make sure their residency is diversified as well. Why not have a portfolio of passports, too?”