Taxpayer Identifying Number Law and Legal Definition

According to 31 CFR 306.2 [Title 31 -- Money and Finance: Treasury; Subtitle B -- Regulations Relating to Money and Finance; Chapter II -- Fiscal Service, Department of the Treasury; Subchapter B -- Bureau of the Public Debt; Part 306 -- General Regulations Governing U.S. Securities; Subpart A -- General Information], taxpayer identifying number means “the appropriate identifying number as required on tax returns and other documents submitted to the Internal Revenue Service, i.e., an individual's social security account number or an employer identification number. A social security account number is composed of nine digits separated by two hyphens, for example, 123-45-6789; an employer identification number is composed of nine digits separated by one hyphen, for example, 12-3456789. The hyphens are an essential part of the numbers and must be included.”