Vendors and Customers

Vendor/Customer update processing is essential to accurate and timely vendor payments, customer refunds, and tax reporting. Departments are responsible for the quality and authenticity of data entered on VCC/VCM transactions, and are responsible for coordinating and maintaining their vendor and customer relationships. This includes accepting changes only from authorized vendor personnel. 

Unless requested by an authorized vendor/customer, departments should not make any additions or modifications to the Vendor/Customer Table (VCUST).


The Vendor/Customer update process


1. Departments receive paperwork directly from an authorized vendor.
2. Departments input the information in MMARS consistent with the information received from the vendor.

3. Departments save and validate the document (VCC/VCM) in MMARS.

4. Departments mail original W-9s and any additional back-up documentation to the Office of the Comptroller for final update in MMARS. The VCC or VCM Doc ID must be clearly written on the top of the W-9 form. Incomplete or inaccurate W-9s, VCCs, and/or VCMs will be returned to the Department's MMARS liaison for correction and re-submission.


Departments should refer to the Vendor/Customer Job Aids* for more information.


*Job Aids can be viewed only inside state government.


William McNamara, Comptroller of the Commonwealth

One Ashburton Place, 9th Floor, Boston MA 02108

For your protection, please do not email personal information (e.g. Social Security Number, Bank Account Number, Passwords).

For assistance, please call us at

(617) 727-5000

  • Twitter
  • Facebook
  • LinkedIn
  • Instagram