Merger or Acquisition? 5 Steps to Merge Vendors into Your Vendor Master File

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I’ve been there.  Your company acquires another company and now you have inherited their vendors, good or bad.  Rarely does Vendor Maintenance have control over the state of the acquired company’s vendor records. Further, there may be no leverage to require a clean-up prior to adding those vendors to your vendor master file.  There is, however, a 5-step process that can minimize impact. 

Follow these 5 steps to minimize the potential for adding inaccurate and/or fraudulent vendors to your vendor master file.


  • Step 1:  Create a Vendor Template - If the Vendor Maintenance team is handling the vendor add process, require that the acquired company export vendors out of their system into the vendor template that includes all the required fields from your Accounting System/ERP.  This will help to ensure you receive the required data needed.


  • Step 2:  Request IRS Tax Information – If your company will assume responsibility for the annual tax files for the current year, request invoice and payment data from January 1st.  For prior year corrections, request invoice and payment data as well as copies of tax filings and 1099s/1042s for the past four (4) years.

  •  Step 3:  Follow Your Normal Validation Process

    • Request Documents - Require the same documentation that a new vendor being onboarded needs to submit.  This may not be possible but ask in case the company has those documents attached to their current vendor record.

    • Perform IRS Bulk TIN Match – Reach out to vendors that are not successful and request an IRS W-9 (US) or IRS W-8x (Non-US/Foreign) form.

    • Verify Banking Details – Validate bank ABA Routing #s, SWIFT Codes and IBANs. Validate Bank Account Name and Bank Account Number match using or a reseller such as Reach out to vendors for those that do not match. 

    • Sanction and Exclusion Lists – Verify vendor Legal Name and Bank Name against the list.  Bulk uploads can be done with paid subscriptions only.  Reach out to leadership if any vendors or vendor banks appear on this list. 

  • Step 4:  Add Vendors to Vendor Master File – Add the legacy vendor id on the vendor record.  Include in the comments a standardized statement with the acquisition information and the path to where the vendor acquisition file will be stored. 



  • Step 5:  Create a Vendor Mapping File –  This is a separate file that can be shared outside of Vendor Maintenance with Sensitive Personal Information (SPI) omitted or masked. Include the legacy vendor ID and new vendor ID.  Other details can be included to verify that key data matches between the legacy system and your Accounting System/ERP based on the acquisition requirements. 


The process is complete!  Your new validated vendors are added to your Vendor Master File.  Let me know if I can help.

Debra R Richardson


Debra is an accounts payable speaker, consultant, and trainer with over 20 years of experience in AP, AR, general ledger, and financial reporting for Fortune 500 companies including Verizon, General Motors and Aramark.

For the past eight years, Debra has focused on Global Vendor Maintenance, and implemented a vendor self-registration portal for 140k+ global vendors across five Accounting Systems/ERPs. In her consultancy, she focuses on internal controls and authentication to prevent fraud in the vendor master file.