What Is Form W-9?
The Request for Taxpayer Identification Number and Certification is an IRS form under which a US person provides a taxpayer identification number to a requester.
Also known as: Request for Taxpayer Identification Number and Certification, W-9 form.
How Form W-9 works
Form W-9 is requested by a payer, bank, broker or platform which must file an information return with the IRS, and the US person completing the form certifies a correct taxpayer identification number, generally an SSN or EIN, together with exemption codes where relevant. The decisive question is US person status, which covers US citizens and resident aliens wherever they live, as well as domestic partnerships, corporations, estates and trusts. A missing or incorrect number can trigger backup withholding, currently 24% of reportable payments according to IRS requester instructions. Foreign persons use the appropriate Form W-8 or Form 8233 instead, and the completed W-9 stays with the requester rather than going to the IRS.
Form W-9 vs Form W-8BEN
Unlike Form W-8BEN, which certifies foreign status for a non-resident alien individual, Form W-9 certifies US person status and a taxpayer identification number for information reporting.
Example
Illustrative example: A US citizen who has lived in Country A for several years opens a brokerage account with a US firm and is asked for tax documentation. Because citizenship keeps US person status, the citizen completes Form W-9 with an SSN, and the broker reports income on information returns.
Common misconception
Myth: A US citizen resident abroad for years can complete Form W-8BEN instead of Form W-9.
Reality: A US citizen remains a US person for Form W-9 purposes regardless of residence, so Form W-8BEN, which certifies foreign status, does not fit that profile.
Frequently asked questions
Do US citizens living abroad fill out a W-9?
Form W-9 applies to US citizens living abroad, because the IRS defines US persons to include every US citizen, irrespective of country of residence.
What is the difference between a W-9 and a W-8BEN?
Form W-9 certifies a US person's taxpayer identification number, whereas Form W-8BEN certifies foreign status of a non-resident alien individual for US withholding.
Related terms
- US Person — Status which Form W-9 certifies
- Form W-8BEN — Foreign-status counterpart often confused with W-9
- Tax Identification Number (TIN) — Number certified on the form
- Accidental American — Profile often surprised by W-9 requests
Related guides
- Global tax reform and US digital nomads — US obligations which follow citizens abroad
- Accounting and bookkeeping for digital nomads — Documentation requested by banks and platforms
Sources
Last verified: 2026-10-08. This entry is general information, not tax or legal advice; rules vary by country and change over time.
