What is Form W-9?
Form W-9 is the IRS form a business asks an independent contractor (or any payee who'll receive a 1099) to fill out so it has the contractor's correct legal name, business structure, and TIN (taxpayer identification number) for year-end 1099 reporting.
Full explanation
Form W-9 (Request for Taxpayer Identification Number and Certification) is collected BEFORE payments start, not after. The business uses the information to file the eventual 1099-NEC or 1099-MISC accurately — the contractor's legal name (matching their tax return), business structure (sole proprietor, LLC, S-corp, partnership), and TIN (either SSN for individuals or EIN for entities).
If a contractor refuses to provide a W-9 or provides clearly false information, the business is required to start "backup withholding" — 24% of every payment withheld and remitted to the IRS — until the contractor furnishes valid information. This is a strong incentive to collect W-9s upfront before sending any payment.
The W-9 is NOT filed with the IRS by either party. The business keeps it on file (typically for at least 4 years) to support the 1099 reporting accuracy. The contractor signs the form certifying the TIN is correct under penalty of perjury. Updated W-9s should be collected whenever a contractor's legal name, business structure, or TIN changes.
W-9 vs W-4: W-9 is for non-employee contractors (1099 reporting). W-4 is for W-2 employees (federal income-tax withholding). The two forms collect different information for different purposes — never substitute one for the other.
Frequently asked questions about Form W-9
Who needs to fill out a W-9?
Any independent contractor, freelancer, attorney, vendor, or other non-employee who will be paid $600+ in a year by a business that needs to file a 1099 for them. Also some banks and brokerages request W-9 to support 1099-INT or 1099-B reporting.
What happens if I don't fill out a W-9?
The paying business is required to start backup withholding — 24% of every payment withheld and remitted to the IRS — until you furnish the W-9. You'll get the withheld amount back when you file your tax return, but it disrupts cash flow until then.
Is a W-9 filed with the IRS?
No. The W-9 stays with the business that requested it (kept for their records). The IRS sees the information indirectly through the 1099 filed at year end, which uses the W-9 data.