A Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a nine-digit number the IRS assigns in the following format: XX-XXXXXXXX. However, for employee plans, an alpha (for example, P) or the plan number (e.g. 003) may follow the TIN/EIN.
The IRS uses the number to identify taxpayers that are required to file various business tax returns. TINs are used by employers, sole proprietors, corporations, partnerships, nonprofit associations, trusts, estates of decedents, government agencies, certain individuals, and other business entities.
Warning: Please be advised that it is against the law to use a TIN for anything other than business use. A TIN cannot be used as a Social Security Number.
Please visit the Internal Revenue Service (IRS) web site for more information if you do not know your company's TIN, or need information on how to apply for one.