What is a taxpayer identification number?

A taxpayer identification number is a number assigned to a taxpaying entity for the purposes of identification by the Internal Revenue Service. As of 2015, this identification number can be issued by either the IRS itself or by the Social Security Administration.

The SSA assigns independent taxpayers with a Social Security number. Other types of taxpayer identification numbers, such as the Employer Identification Number, are assigned by the IRS to corporations or individuals who do not qualify for an SSN. The taxpayer identification number is necessary as it is used for tax return filings, claiming tax treaty benefits and claiming certain exemptions.