DUNS Number Explained: Business Identity, Credit, and Compliance
What is a DUNS number? The Data Universal Numbering System (D-U-N-S®) Number is a unique nine-digit business identifier issued by Dun & Bradstreet (D&B). It is used globally to identify business entities, link corporate relationships, and support workflows such as government contracting, credit reporting, supplier onboarding, and international trade.
Why People Look Up a DUNS Number
Most users researching DUNS have one of two goals: (1) comply with a contract or registration requirement, or (2) build business credit. Understanding your “why” helps you complete the right steps in the right order.
- Contracting/compliance: You need a business identifier for SAM registration, vendor onboarding, grants, or supplier qualification.
- Credit building: You want to establish a D&B credit profile so lenders and vendors can evaluate your business.
Business Identity Stack (How IDs Work Together)
Businesses often confuse EIN, DUNS, SIC, and NAICS. They are not competing identifiers—they solve different problems. This “identity stack” shows how they fit together.
Tax identity (IRS): Identifies your business for federal tax reporting and payroll.
Common use: Banking, payroll, tax filings, vendor forms that require a tax ID.
Business entity identity (D&B): Anchors a global business profile and links corporate relationships.
Common use: Government contracting, supplier onboarding, credit reporting, international trade workflows.
Industry classification (North America): Describes what your business does for economic statistics and many B2B segmentation workflows.
Common use: Government reporting, market sizing, analytics, and operational segmentation.
Legacy industry classification: Still widely used across B2B data systems, compliance workflows, and historical comparability.
Common use: Sales/marketing segmentation, legacy datasets, longitudinal reporting, and industry benchmarking.
SICCODE.com focus: If you need to state your industry accurately (for contracts, credit profiles, or vendor onboarding), the highest-impact step is selecting the correct SIC and NAICS codes before you submit profiles to third parties.
Identity Comparison Table
If you are unsure which identifier you need, use this quick-reference table:
| Identifier | Issued by | What it identifies | Most common “why” |
|---|---|---|---|
| EIN | IRS | Your tax entity for reporting and payroll | Banking, payroll, tax filings |
| DUNS | Dun & Bradstreet | Your business identity and corporate linkage profile | Contracts, vendor onboarding, business credit profile |
| NAICS / SIC | NAICS: U.S./Canada/Mexico; SIC: legacy U.S. standard | Your industry activity (what you do) | Classification for bids, reporting, segmentation, and compliance |
DUNS, PAYDEX & Business Credit (The Credit-Building Intent)
One of the most common reasons small businesses seek a DUNS number is to establish a D&B business credit profile. In practice, the DUNS number is the anchor that ties your trade experiences and business identity to a single record.
- Why it matters: Without a DUNS number, many lenders and vendors may not have a consistent way to recognize your business as a distinct credit entity.
- What to expect: As your business builds verified history, D&B can generate business credit indicators (including the PAYDEX® score) that reflect payment performance.
- Practical takeaway: Your identity data (name, address, industry, and contacts) should be consistent across systems to avoid fragmented or duplicate credit records.
Risk signal: Your industry classification can influence how risk teams interpret your business. If your business model changes, confirm your updated SIC/NAICS codes first, then update third-party profiles to avoid mismatches and misunderstandings.
Government Contracting Context
For contracting, DUNS numbers are frequently used to link your company identity across procurement systems. Many workflows begin with SAM registration and may lead to additional identifiers depending on agency and contract type.
- SAM registration: DUNS is often used for vendor registration and identity tracking.
- CAGE code: A DUNS number may be required to obtain a CAGE code for certain government contracting workflows.
- Operational readiness: Accurate classification (SIC/NAICS) supports bid eligibility, set-aside programs, and reporting alignment.
Where to Get a DUNS Number
DUNS numbers are issued directly by Dun & Bradstreet:
- Register through Dun & Bradstreet.
- Submit your business information for verification.
- Once verified, your nine-digit DUNS number is assigned.
For federal contracting guidance, visit the SBA: Basic Requirements for Federal Contracting.
SIC/NAICS Classification Help (Before You Submit Profiles)
Many registration and onboarding flows require SIC and NAICS codes. These codes describe your primary activity and are commonly used to evaluate eligibility, segment vendors, and support compliance reporting.
- Find your NAICS code: What is a NAICS Code?
- Find your SIC code: What is a SIC Code?
- Browse directories: SIC Code Lookup / Directory and NAICS Code Lookup / Directory
Best practice: If you are registering for contracting or updating a D&B profile, confirm your SIC/NAICS selection first to prevent downstream mismatches in vendor systems, credit records, and reporting.
Managing Your D&B Profile (Data Maintenance)
Data decay is one of the biggest causes of procurement delays and credit-profile confusion. If your business changes, update your records quickly and consistently:
- Moved locations: Update your address and phone to prevent verification failures and duplicate records.
- Changed your business model: Re-check your primary SIC/NAICS codes and update classification to match your current operations.
- Expanded or restructured: Ensure legal name, DBA, and entity structure are consistent across profiles.
- Ongoing hygiene: Keep websites/domains, key contacts, and workforce size current to reduce “stale entity” flags.
Frequently Asked Questions
- Is a DUNS number free?
Businesses registering for government contracting or grants can typically obtain a DUNS number at no cost through the appropriate workflow. - Is a DUNS number the same as SAM registration?
No. A DUNS number identifies your business entity. SAM is the federal system that uses identifiers as part of vendor registration. - Do I still need SIC and NAICS codes?
Yes. DUNS identifies your business; SIC and NAICS classify what your business does. - Can one company have multiple DUNS numbers?
Yes. Different physical locations or legal entities can have separate DUNS records depending on how they are registered and verified. - What should I do if my business changes industry focus?
First, confirm your updated SIC/NAICS codes, then update third-party profiles (including D&B) to match your current operations and prevent classification mismatch.