What Is an IRS W-9 Form?

An IRS W-9 form, also known as the Request for Taxpayer Identification Number and Certification is a document that is submitted by an individual to his or her employer or any organization that is required to file a W-2, according to the IRS and TurboTax. A W-9 form is not submitted directly to the IRS but is used by an employer at the end of a financial year to report the wages and salaries paid to an employee, explains TurboTax.

W-9 forms are also used by employers as part of their payroll process to correctly identify an employee's Taxpayer Identification Number, according to TurboTax. This form is also used to gather information about wages paid to independent contractors, interest payments on mortgages, proceeds from real estate sales or purchases, and IRA contributions, according to the IRS and the Defense Tax Group.

Financial entities that disburse payments to employees or contractors are responsible for collecting W-9 forms, but the filing of these forms is not mandated by the IRS. In some cases, the IRS requires employers to place a percentage of an employee's paycheck into a backup withholding reserve fund that is used to pay the employee's personal income tax, reports TurboTax. However, it is the employee's responsibility to notify their employer of such a requirement.