What are the three types of Taxpayer Identification Numbers (TINs) I keep hearing about?
A TIN is either a Social Security Number (SSN) issued to individuals by the Social Security Administration (SSA), an Employer Identification Number (EIN) issued by the Internal Revenue Service (IRS) or an Individual Taxpayer Identification Number (ITIN) issued by the IRS, normally to nonresident aliens. Each of these TINs consists of nine numeric digits.