IRS Form W-9 is a Request for Taxpayer Identification Number and Certification used by businesses to collect a vendor's, contractor's, or partner's Social Security Number (SSN) or Employer Identification Number (EIN) for 1099 reporting purposes.
Form W-9 (irs.gov/forms-pubs/about-form-w-9) is the standard IRS form businesses use to collect taxpayer identification information from U.S. persons and entities before making reportable payments. When a business pays a contractor, freelancer, vendor, or partner $600 or more in a calendar year for services, rents, royalties, or other reportable payments, it must file a 1099 information return with the IRS and provide a copy to the payee — and the W-9 supplies the tax identification data needed to do that. The form collects: legal name (individual or business entity name), business name/disregarded entity name (if different), federal tax classification (individual/sole proprietor, C-corp, S-corp, partnership, LLC, trust, estate), exemption codes (for exempt payees and FATCA), address, taxpayer identification number (SSN for individuals, EIN for businesses), and the payee's certification signature that the information is accurate and the payee is not subject to backup withholding. Backup withholding: if a vendor fails to provide a valid W-9 or provides an incorrect TIN, the payer must withhold 24% of payments as backup withholding under IRC §3406 and remit it to the IRS (irs.gov/businesses/small-businesses-self-employed/backup-withholding). Businesses should collect W-9s before issuing the first payment. LLCs must indicate their tax classification on the W-9 (C-corp, S-corp, partnership, or disregarded entity/sole proprietor), which determines how they are reported on information returns. The current Form W-9 instructions are at irs.gov/pub/irs-pdf/fw9.pdf.
Any time you make a reportable payment of $600 or more to a U.S. person or entity (contractors, vendors, landlords, attorneys, etc.) in a calendar year and need to file a 1099. Collect the W-9 before the first payment to avoid backup withholding complications. You don't need a W-9 from C-corporations or S-corporations for most payments (they are exempt payees for 1099-NEC/MISC), but you do need one from LLC vendors to confirm their tax classification (irs.gov/forms-pubs/about-form-w-9).
If a payee refuses to provide a W-9, provides an incorrect TIN, or has been notified by the IRS of underreporting, the payer must withhold 24% of reportable payments as backup withholding under IRC §3406 and remit it using Form 945. The W-9 includes a certification that the payee is NOT subject to backup withholding. Payers who fail to collect W-9s and fail to withhold when required can face IRS penalties (irs.gov/businesses/small-businesses-self-employed/backup-withholding).
No. Form W-4 (Employee's Withholding Certificate) is completed by employees to set federal income tax withholding on wages — it's an employment relationship form. Form W-9 is for independent contractors, vendors, and other non-employees — it establishes taxpayer identification for 1099 reporting. Misclassifying an employee as a contractor (and using W-9 instead of W-4) is an IRS audit trigger and exposes the business to employment tax liability under IRC §3509 (irs.gov/businesses/small-businesses-self-employed/independent-contractor-self-employed-or-employee).