The W-9 is the most basic vendor document, and it is the one that causes the most end-of-year problems when it was not collected correctly — or at all.
This guide covers everything you need to know to get W-9 collection right.
When You Are Required to Collect a W-9
The IRS requires you to collect a W-9 from any U.S. person or entity you pay more than $600 in a calendar year for services. This includes independent contractors, freelancers, LLCs, and sole proprietors. Payments for rent, legal services, and other specific services also trigger the requirement regardless of amount.
Corporations (C-corps and S-corps) are generally exempt from 1099 reporting, but you should still collect a W-9 to document the exemption.
The W-9 gives you the information you need to file a 1099-NEC at year end. If you pay a vendor without a W-9 on file and they do not provide their TIN, you are required to withhold 24% of all payments for backup withholding and remit that amount to the IRS.
Collect the W-9 before the first payment. Not after.
What Is on a W-9
The W-9 (Request for Taxpayer Identification Number and Certification) collects:
- Name — the individual's legal name or the business name
- Business name / DBA — if different from the legal name
- Federal tax classification — individual/sole proprietor, LLC (with tax treatment), C-corp, S-corp, partnership, trust, or other
- Address — used for mailing the 1099 at year end
- TIN — either a Social Security Number (for individuals) or Employer Identification Number (for businesses)
- Signature and date — certifying the information is correct
What to Verify on Every W-9
Name and TIN must match. The IRS cross-references 1099s against their records. If the name and TIN do not match what the IRS has on file, you will receive a CP2100 notice — the "B notice" — which triggers a backup withholding requirement. This is an operational headache you want to avoid.
You can verify name/TIN combinations using the IRS TIN Matching Program before filing your 1099s.
Entity type must be selected. This is frequently left blank, and it matters — it determines whether you need to file a 1099-NEC, 1099-MISC, or no 1099 at all.
Signature and date must be present. An unsigned W-9 is not valid. The signature is a legal certification that the information is accurate.
Address must be legible and complete. You will use this to mail the 1099 if you do not have an email address for the vendor.
Common W-9 Mistakes
Accepting a W-9 with a Social Security Number from a business entity. If the form says "LLC" but the TIN is formatted like an SSN (XXX-XX-XXXX), verify whether the LLC is a single-member LLC treated as a disregarded entity. This is actually allowed — but you need to understand which type of entity you are working with.
Not getting an updated W-9 when information changes. If a vendor changes their name, entity type, or TIN, you need a new W-9. Request updates whenever you have reason to believe the information may have changed.
Storing W-9s insecurely. W-9s contain Social Security Numbers or EINs. They must be stored securely — encrypted at rest, access-controlled, and not in a shared Google Drive folder accessible to everyone in the company.
How Long to Keep W-9s
The IRS does not specify a retention period for W-9s, but the standard guidance is to retain them for at least four years after the tax year in which the information was used. Since W-9s are referenced for 1099 filing, keep them for at least four years after the last 1099 filed using that W-9.
What Happens If You Do Not Collect a W-9
If you pay a vendor more than $600 without a W-9 on file and cannot obtain a valid TIN, you are required to withhold 24% of all payments and remit to the IRS. This creates an accounting burden and can damage your vendor relationship.
If the vendor refuses to provide a W-9, you have the right to withhold 28% of each payment until they comply. Document every request for the W-9 and their refusal in case of an IRS audit.
Making W-9 Collection Systematic
The operational goal is to make W-9 collection a mandatory step before any vendor is activated in your payment system — not an afterthought when 1099 season arrives in January.
A vendor compliance platform enforces this at onboarding: the vendor cannot be cleared for payment until a valid W-9 is on file. The platform validates that required fields are present and stores the form securely with access controls appropriate for tax identification data.