The title of Form W-8ECI is Certificate of Foreign Person’s Claim That Income Is Effectively Connected With the Conduct of a Trade or Business in the United States. What Types of 1099 Income are Subject to Backup Withholding? According to the IRS in its Topic No. 37, Backup Withholding ...
Boxes A through F all provide identifying information: your Social Security number, your employer's tax ID number or EIN, everyone's addresses, and their full legal name. Box D is a control number that identifies your unique Form W-2 document in your employer's records. The numbered boxes ...