National Insurance number
The National Insurance number is a number used in the United Kingdom in the administration of the National Insurance or social security system. It is also used for some purposes in the UK tax system. The number is described by the United Kingdom government as a "personal account number".
Social Security (United States)
The analogy to insurance, however, is limited by the fact that paying FICA taxes creates no legal right to benefits and by the extent to which Social Security is, in fact, funded by FICA taxes. During 2011 and 2012, for example, FICA tax revenue was insufficient to maintain Social Security's solvency without transfers from general revenues. These transfers added to the general budget deficit like general program spending.