The Form W-9 is used in the United States income tax system by any third party who must file an information return with the Internal Revenue Service (IRS). The form is not actually sent to the IRS, rather it is held by the individual who files the information return for verification purposes, and is eventually reported on the Form-1099.

W-9s are required for business-to-business relationships where more than $600 is paid in the calendar year.

If you need one for your event, you can download it here.