Taxpayer Identification Number (TIN)

Identifying number assigned to a taxpayer. The TIN for an individual is the individual's Social Security number. An Employer Identification Number (EIN) is used for corporations, partnerships, estates and trusts.

IRS identification number needed before most bank accounts can be opened. For individuals and sole proprietors, the tax number is the individual's Social Security number. A business tax identification number is the employer's identification number, required of corporations, nonprofit organizations, associations, and partnerships. A bank's liability for noncompliance with the IRS rule after January 1, 1984 is $50 per account. A bank must also withhold 20% of the interest earned on the account in a special escrow account. See also Backup Withholding.