Citizenship is the relationship between an individual and a sovereign State, defined by the laws of that State and involving corresponding duties and rights. Principal grounds for acquiring citizenship are birth within a certain territory, descent from a citizen parent, marriage to a citizen, and naturalization. The conditions under which the privilege of naturalization is granted vary from State to State, but family relationships or lengthy periods of residence are usually essential, besides character and other requirements. While residence is granted to investors and wealthy individuals in most countries, there are only very few countries now which have clear provisions in their laws to grant citizenship for economic considerations and without any residence requirements.

The USA, Canada, Belgium, Australia, Singapore, and the United Kingdom are countries which offer residence to wealthy individuals and investors, as well as citizenship at a later stage. Other countries offer citizenship-for-investment programs, sometimes also known as Economic Citizenship Programs.