W-9 Instructions

Click here to access the Vendor W-9 Upload Form.

As part of onboarding suppliers, the university requires a W-9 from anyone that is added to the university supplier database. 

This not only covers any potential tax requirements, but it assists the university in validating identity and ensuring that vendor records are not duplicated. Supplier Services will ask the supplier/individual for a W-9 when a new record is added.  

NOTE: A W-9, or any documents with personally-identifiable information, should NOT be electronically attached to the Vendor document in KFS under any circumstances. 

The W-9 Process

  • Department creates a new vendor request.
  • Supplier Services will approve the request as inactive, until the W-9 has been received from the vendor; the initiator will receive an FYI in their KFS Action List.
  • Supplier Services will send a request to the vendor, with instructions on how to upload the W-9.
  • When the vendor uploads the W-9, Supplier Services will update the record and activate it.
  • The original initiator will receive an FYI in their KFS Action List that the vendor is now active and ready to be used.

If you prefer visual aids, we also have a flow chart (PDF) of the process.

Receiving a W-9

While it is preferable that Supplier Services requests the W-9 from the vendor/individual, there may be situations where it is easier and more comfortable for the payee if the department collects the W-9. Examples are Human Subjects and speakers receiving Honoraria payments. In these cases, you can assist with the Vendor W-9 Upload Form

You will need a vendor ID from KFS, so it is best if you process the vendor request FIRST before uploading the W-9.  Add a note on the vendor request that you will be receiving and uploading the W-9.  That way, Supplier Services will not also request it.

Security Considerations

A W-9 contains personal information that requires protection. Once the W-9 is uploaded, make sure it is destroyed or securely stored. We recommend that you consult with your security team to ensure that any electronic W-9 files have been properly secured or destroyed.


If you have any questions about vendor onboarding or W-9 requirements, contact Supplier Services at vendordesk@ucdavis.edu.