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 Institution
The Social Security Institution () is the governing authority of the Turkish social security system. It was established by the Social Security Institution Law No:5502, which was published in the Official Gazette No: 26173 on June 20, 2006. This brought five different retirement systems that affected civil servants, contractual paid workers, agricultural paid workers, and self-employed workers into a single retirement system offering equal actuarial rights and obligations.