Duplicate DUNS Numbers: How to Merge or Resolve

Scenario: Assigned Automatically Without Your Knowledge

D&B doesn't only assign DUNS numbers when someone applies directly — it can also independently profile a business it becomes aware of through public records, government filings, or business directories, and assign a number without the business ever requesting one.

• Years later, when the business (or an employee unaware of this) applies directly for a DUNS number, D&B may issue a second one instead of recognizing the existing record.
• This is especially common for older, well-established businesses that were profiled long before anyone at the company thought to check.
• Neither record is "wrong" on its own — they simply both represent the same business independently.

✔ THE FIX

Search D&B's lookup tool using your business name and address before assuming you need a new number, and if two records surface, request a merge rather than continuing to use either in isolation.

Scenario: A Rename or Move Created a New Record

This happens when a legal name change or office move is handled as a brand-new DUNS application instead of an update to the existing record — often because whoever filed the paperwork didn't realize the business already had a number.

• The old record (under the previous name or address) often remains active in D&B's system, sitting alongside the new one.
• This fragments payment history across both records, since vendors may have reported trade data to whichever DUNS number they had on file at the time.
• See our Update Name/Address guide for how to properly update an existing record without triggering this issue.

✔ THE FIX

Identify which record is older or more established, and request that D&B merge the newer record into it, carrying forward the correct current name and address.

Scenario: Mergers & Acquisitions

When two companies combine, each one may have had its own established DUNS number and payment history prior to the merger — and simply choosing to use one going forward doesn't automatically resolve the other in D&B's system.

• Depending on the deal structure, one entity may be legally absorbed into the other, or both may continue to exist as related but distinct entities.
• If the intent is for one combined entity to operate going forward, the "extra" DUNS number from the absorbed company generally needs to be formally resolved with D&B.
• This is more complex than a simple rename, since it may involve reconciling two separate sets of payment and financial history.

✔ THE FIX

Provide D&B with the merger or acquisition documentation clarifying which entity legally continues, and request a formal review of how the two records should be resolved.

How to Request a Merge — Step by Step

1. Confirm both numbers represent the same legal entity. Use the comparison above to rule out an intentional multi-location setup before proceeding.
2. Gather both DUNS numbers. Look them up directly through D&B if you only know one, using your business name and address to search for others.
3. Collect supporting documentation. Incorporation certificates, registration filings, or merger/acquisition documents help D&B confirm which record should be treated as authoritative.
4. Contact D&B support directly to request a merge. Clearly state that you believe two DUNS numbers represent the same business and provide both numbers.
5. Indicate a preference if you have one. If one record has a more complete or accurate history, you can note this, though D&B makes the final call on which record survives.
6. Verify the result once complete. Check D&B's own record (not a third-party copy) to confirm only one active number remains and that your details are correct.

How to Prevent This Going Forward

• Always search before applying. Look up your business by name and address before submitting any new DUNS application, especially for older or previously government-registered businesses.
• Update, don't reapply, after a rename or move. Use D&B's profile update process rather than submitting a fresh application — see our Update Name/Address guide.
• Centralize who manages your DUNS number internally. Duplicate numbers often happen when multiple people (an old employee, a new hire, an outside agency) each assume no number exists yet.
• Document your DUNS number clearly during any merger or acquisition planning. Resolve the numbering question as part of the deal, not as an afterthought.