CAGE, UEI and NAICS: What a Prime's Supplier-Vetting Search Actually Resolves

Defence procurement · 5 min read · 8 cited facts

When a prime's procurement team vets a supplier, the search does not start on the supplier's website. It starts in SAM.gov, and it resolves three identifiers that answer three different questions: where you are (the CAGE code), whether you are registered to be found and paid (the UEI), and what the government thinks you do (the NAICS code). They come from three different issuers, and conflating them is how vetting stalls. We will use a real example throughout — our own: CAGE 4J0A3, UEI JQ1MBE7MJW81, NAICS 334515, all public record and checkable in SAM.gov without taking our word for any of it.

CAGE: a five-character code for a location, issued by DLA

The Commercial and Government Entity code is defined in FAR 52.204-16 and 52.204-18: an identifier assigned to entities in the United States and its outlying areas by the Defense Logistics Agency's CAGE Branch, 'to identify a commercial or government entity by unique location'. That last phrase is the part suppliers miss. A CAGE code names a place, not a corporate family — a company with three performing facilities can hold three codes, and FAR 52.204-18 obliges a contractor to maintain the correct code for each location of contract performance, including subcontract performance. US entities are assigned one automatically during SAM registration; entities outside the US need an NCAGE, assigned through NATO's codification system and recorded by DLA in the same master file. Source: FAR 52.204-16 and 52.204-18 — acquisition.gov. Retrieved 2026-08-24.

The format is five alphanumeric characters. Ours, 4J0A3, resolves to the Tustin, California facility that builds and services the systems — the same address a solicitation response carries. When a solicitation asks for the word 'CAGE' in front of the number, that is FAR 52.204-16(b) speaking, and the code must match the name and address on the offer. Source: US CAGE and NCAGE Registration Procedures — DoD Procurement Toolbox. Retrieved 2026-08-24.

UEI: the SAM.gov key that replaced DUNS

The Unique Entity ID is a 12-character alphanumeric identifier generated by SAM.gov itself. On 4 April 2022 it replaced the proprietary DUNS number as the authoritative identifier across federal award systems — GSA's stated reason was to separate the government's identifier from any single commercial validation vendor. Two format details save transcription time: the letters O and I are never used, and the first character is never zero. The transition did not touch CAGE codes. Source: 'GSA Systems Switch to Unique Entity ID (SAM) on April 4, 2022' and GSA UEI stakeholder FAQ — US General Services Administration. Retrieved 2026-08-24.

The detail that matters for vetting: a UEI is not proof of an active registration. SAM.gov will issue a UEI to an entity that only needs to report as a sub-awardee and never completes a registration, and a full registration, once made, lapses unless renewed every 365 days. An entity that quotes a UEI has proved it exists in SAM.gov — nothing more. Check the registration status behind the identifier; SAM.gov shows it, and search resolves by legal business name, CAGE code or UEI. Source: SAM.gov entity registration pages — SAM.gov. Retrieved 2026-08-24.

NAICS: the code the size standard hangs on

The North American Industry Classification System is the standard federal statistical agencies use to classify business establishments, published for the US by the Census Bureau, currently in the 2022 revision. 334515 is 'Instrument Manufacturing for Measuring and Testing Electricity and Electrical Signals' — the code that covers the benches this site writes about, the ones that hold an aircraft bus inside MIL-STD-704F Table I limits. Source: 2022 NAICS record for 334515 — US Census Bureau. Retrieved 2026-08-24.

NAICS is where 'small business' stops being a self-description. The contracting officer designates a NAICS code for each contract under 13 CFR 121.402, and SBA's size-standard table at 13 CFR 121.201 attaches a threshold to each code — for 334515 the standard is 750 employees. A firm can be small under one code and other-than-small under another on the same day; the code on the solicitation is the one a set-aside is judged against. A supplier can also hold several: ours lists 811219, Other Electronic and Precision Equipment Repair and Maintenance, and 336413, Other Aircraft Parts and Auxiliary Equipment Manufacturing, alongside the primary. Source: SBA Table of Size Standards, 13 CFR 121.201 — US Small Business Administration. Retrieved 2026-08-24.

• Resolve the CAGE code and confirm the address matches the facility that will actually perform the work.
• Look behind the UEI: is the SAM registration active, and when does it expire? A bare UEI proves existence, not standing.
• Read the supplier's NAICS codes and size representations against the code your solicitation carries — not against the supplier's preferred code.

What none of the three identifiers carries is capability. They anchor an entity; they say nothing about whether it has delivered. Delivery history lives in the public award record — FPDS and USAspending — which is why our government capability page leads with contracting agencies and prime customers rather than adjectives. An identifier gets a supplier found; the award record gets it trusted.