Form W-9 is used in the United States income tax system by a third party who must file an information return with the Internal Revenue Service. It requests the name, address, and taxpayer identification information of a taxpayer.
A W-9 form is an Internal Revenue Service (IRS) form, also known as a Request for Taxpayer Identification Number and Certification form, which is used to confirm a person’s taxpayer identification number (TIN). This confirmation can be requested for either an individual defined as a U.S. citizen or a person defined as a resident alien.
The information obtained on a W-9 form is most often used to create a version of the Form 1099. A Form 1099 contains information about any income that may have been received by the TIN holder that would not normally be listed on a W-2. This includes, but is not limited to, income paid to a person as part of a contract; certain real estate transactions; mortgage interest paid by an individual; dividends paid against an investment; and various other financial transactions.
The IRS requires those who are not defined as U.S. citizens or resident aliens to use the appropriate W-8 form in place of a W-9 form.
Even though employees are legally required to supply certain personal information to their employers, an employee's privacy is protected by law. An employer who discloses an employee's personal information in any unauthorized way may be subjected to civil and criminal prosecution.