DUNS vs UEI for an LLC: D&B Credit, SAM.gov, and the 2022 Federal Switch

What changed in April 2022 and what stayed the same

Before April 4, 2022, the federal government used the DUNS number as the standard identifier for entities receiving federal contracts and grants. SAM.gov, the central federal entity registration system, required a DUNS number as part of the registration. Federal contractors had to obtain a DUNS from Dun & Bradstreet, then register that DUNS on SAM.gov.

Effective April 4, 2022, the federal government transitioned to the Unique Entity Identifier (UEI), a 12-character alphanumeric identifier assigned directly by SAM.gov. The transition followed a US government decision in the late 2010s to move the federal identifier in-house, away from a third-party commercial source. SAM.gov now assigns the UEI as part of registration; an applicant does not separately apply for a UEI before reaching SAM.gov.

DUNS for private business credit, separate from federal use

The DUNS number remains the foundational identifier in Dun & Bradstreet's business-credit ecosystem. An LLC building a business-credit profile typically registers for a DUNS at no cost through D&B, then adds Net 30 vendor accounts and a business credit card to build the PAYDEX score and the broader credit profile. The five-step credit-building process is covered in detail in the LLC business credit DUNS guide.

DUNS is also used in some non-federal vendor systems. Large procurement platforms and corporate supplier networks sometimes ask for a DUNS as a verification field. Trade-credit services and some commercial insurance carriers reference DUNS as part of their underwriting. The federal switch to UEI did not change these private uses.

UEI registration on SAM.gov: the path for an LLC

SAM.gov is the federal central contractor registration system. An LLC pursuing federal contracts or grants registers on SAM.gov, and the UEI is assigned during the registration. The process is free; SAM.gov does not charge any fee for UEI assignment or for the registration itself. Several third-party services advertise paid SAM.gov registration assistance, but none of those services are necessary for the registration itself.

1. 1Create or sign in to a SAM.gov account. The account is tied to the individual filer, not to the LLC.
2. 2Start a new entity registration for the LLC. SAM.gov asks for the legal business name, the EIN, the physical business address, and the type of registration (entity for federal awards, or entity-validation-only).
3. 3Validate the entity. SAM.gov runs an entity validation check that confirms the LLC's name and address against public records. The validation can take time; if it fails automatically, the system routes the registration to a manual review.
4. 4Receive the UEI. Once validation passes, SAM.gov assigns the 12-character UEI. The UEI appears on the SAM.gov record and is the federal identifier from that point forward.
5. 5Complete the full registration. For federal contracts (as opposed to federal grants only), additional information is required, including NAICS codes, representations and certifications, and points of contact.
6. 6Receive a CAGE code. SAM.gov assigns a Commercial and Government Entity (CAGE) code automatically during full registration for federal contracting; the CAGE is used by the Department of Defense and some other agencies.

NAICS code selection and what it does for the LLC

The North American Industry Classification System (NAICS) code identifies the LLC's primary industry for federal contracting purposes. SAM.gov registration asks the LLC to select one or more NAICS codes that describe the business. The codes affect which contract opportunities the LLC qualifies for and which size standards apply for small-business determination. A founder selecting NAICS codes for the first time should review the SBA size-standards table for the relevant codes and pick codes that match the LLC's actual or planned business activity.

An LLC operating in multiple categories selects multiple NAICS codes, designating one as the primary. The primary code is what most contracting officers see in the LLC's SAM.gov profile. Secondary codes broaden the LLC's eligibility for contract opportunities in adjacent categories. Changing the codes later is possible through the SAM.gov record update process.

Grants.gov for federal grants in addition to SAM.gov

Federal grants and federal contracts use different application systems. SAM.gov is the central entity registration for both, but the application portal is different. Grants.gov is the central federal grants application portal; applicants register on Grants.gov in addition to SAM.gov to apply for federal grant opportunities.

The Grants.gov registration uses the LLC's UEI from SAM.gov as the link between the two systems. A change to the LLC's address or other information on SAM.gov flows through to Grants.gov automatically when SAM.gov updates the record. The LLC does not need to maintain two separate registration records; the UEI is the link.

Address verification on SAM.gov: what passes and what fails

SAM.gov validates the LLC's physical address against public records during entity validation. The validation checks that the address is a real street address, that it is associated with the LLC's name through public records (state Secretary of State filings, business license records), and that it is not flagged as a non-business address category.

• Passes. A real commercial street address in a save office city that appears on the LLC's state filing, the EIN record, and the LLC's other public records. The address has USPS Delivery Point Validation and is not classified by SAM.gov as a non-business address.
• Often passes with verification. A founder's home address used for the LLC; the address is real but the validation may take longer if the LLC's name is not associated with the address in public records.
• Often fails. A PO Box. SAM.gov requires a physical street address, not a PO Box, for entity registration.
• Often fails. An address that flags as a Commercial Mail Receiving Agency in the address-classification data SAM.gov uses, when the address is not the LLC's actual operating location.

When the LLC needs both DUNS and UEI

An LLC pursuing federal contracts or grants needs the UEI. An LLC building a private business-credit profile needs the DUNS. A single LLC pursuing both tracks needs both identifiers, and the two are obtained from different systems (UEI from SAM.gov, DUNS from D&B). The two identifiers do not connect; an LLC can have one without the other, both, or neither.

When the LLC needs both, the sequence does not matter for the systems themselves but does matter for the LLC's address consistency. Setting up the principal business address before either registration is the cleanest path. The same address fills the SAM.gov entity validation, the DUNS profile at D&B, the EIN record at the IRS, and the bank record. Address consistency across the four records is what keeps the validation and credit profiles from flagging the LLC.

Common mistakes when registering for the UEI

• Paying a third-party service for SAM.gov registration. The registration is free at sam.gov. Paid services exist, but their value is administrative help, not gatekeeping; the LLC can register itself without the service.
• Assuming the LLC still needs a DUNS first to register on SAM.gov. The DUNS is no longer a requirement; SAM.gov assigns the UEI directly.
• Using a PO Box on the SAM.gov registration. PO Boxes fail the physical-address requirement; the registration will not validate.
• Selecting too few or too generic NAICS codes. The codes determine eligibility for contract opportunities and small-business size standards; a thoughtfully selected primary plus a small set of secondary codes is more useful than a single generic code.
• Skipping the annual renewal. The SAM.gov registration expires annually and must be renewed; an expired registration removes the LLC from federal-contract eligibility until renewed.
• Letting the address fall out of sync between SAM.gov and the LLC's other records. Changing the LLC's address requires updating SAM.gov, the IRS (Form 8822-B), the state SOS (Articles of Amendment), and the bank in the same window.

Checklist: registering an LLC on SAM.gov for the UEI

1. 1Confirm the LLC is formed at the state level and has its EIN from the IRS. SAM.gov does not register an LLC; it registers an existing LLC for federal awards.
2. 2Set up the LLC's principal business address through save office onboarding if not yet in place. Confirm the address passes the Address Checker for USPS Delivery Point Validation.
3. 3Create a personal SAM.gov account for the individual who will manage the LLC's registration.
4. 4Start a new entity registration for the LLC; enter the legal name, EIN, and physical business address.
5. 5Pass the entity validation. If the validation fails automatically, follow the SAM.gov resolution path; do not abandon and restart.
6. 6Receive the UEI and (for full registration) the CAGE code. Both appear on the SAM.gov record.
7. 7Select the NAICS codes that describe the LLC's business, with one as primary.
8. 8Complete the representations and certifications for federal contracting, if pursuing contracts rather than grants only.
9. 9Register on Grants.gov using the UEI, if pursuing federal grants.
10. 10Set a calendar reminder to renew the SAM.gov registration annually before it expires.