Form W-9, Request for Taxpayer Identification Number and Certification, is how a business collects the legal name, tax classification and taxpayer identification number of a person or company it pays. You keep the form; it is not sent to the IRS. Its purpose is to let you file accurate information returns, such as Form 1099-NEC, later.
When to request it
The best time is before the first payment, as part of onboarding a new vendor. Once a vendor has been paid, there is less incentive to send paperwork back. A simple rule: no W-9, no first payment. That rule prevents most January scrambles.
Not every vendor needs a 1099, but collecting a W-9 from every new service provider costs little and settles the question later. Corporations are generally exempt from 1099-NEC reporting, with exceptions such as certain payments to attorneys, and the W-9 tells you how the vendor is classified.
What to check on a returned form
- Name on line 1 matches the name associated with the taxpayer identification number. For a single-member LLC that is disregarded for tax, line 1 is usually the owner's name, with the business name on line 2
- Tax classification is checked: individual or sole proprietor, C or S corporation, partnership, trust or estate, or LLC with its tax classification
- TIN is present: a Social Security number or an employer identification number, not both
- Signature and date in Part II
The IRS offers a TIN matching program for authorized payers to check name and number combinations before filing.
Backup withholding
If a payee does not provide a TIN, or the IRS notifies you that the name and TIN do not match, you may be required to start backup withholding on reportable payments and deposit it with the IRS. Collecting a correct W-9 up front is the easiest way to avoid this.
Storing W-9s securely
W-9s contain Social Security numbers. Store them in a secure, access-controlled location, not in email inboxes or shared folders open to everyone. Keep them for as long as you may need to support information returns; see our guide on how long to keep business records.
How we use W-9s in bookkeeping
We record each vendor's tax classification and 1099 status in the accounting system when the vendor is created. Payments are then tracked automatically through the year, and at year end the 1099 list is a report, not a research project.
Storing W-9s securely
W-9s contain taxpayer identification numbers. Store them in an access-controlled folder or your accounting software's vendor record, not in email inboxes.
Request an updated form when a vendor's name or entity changes.
Key terms
Definitions for terms used in this guide, from our small business glossary:
- Exempt and Non-Exempt Employees: Non-exempt employees must receive overtime under federal law; exempt employees meet specific tests that remove that requirement.
- Backup Withholding: Backup withholding is federal income tax a payer must withhold from certain payments when the payee's taxpayer identification number is missing or incorrect.
- Taxpayer Identification Number (TIN): A taxpayer identification number is the number the IRS uses to identify a person or entity, such as an SSN, EIN or ITIN.
