A W-9 Form
must be completed for all new domestic vendors. A new W-9 must be completed if tax classification changes.
W9s are for US based individuals and businesses with either a social security number (SSN) or Employer of Identification number (EIN). Incomplete or illegible documentation will cause delays in processing. This is not required for reimbursements. Refer to http://www.irs.gov/pub/irs-pdf/fw9.pdf
for more information.