The table
| ID | What it is | Who issues it | Format | When you need it |
|---|---|---|---|---|
| UEI | The authoritative federal entity identifier ("Unique Entity ID"), replacing DUNS | SAM.gov (GSA) — generated during validation, free | 12-character alphanumeric | Every federal award interaction since April 2022; UEI-only registration suffices for subcontractors |
| CAGE | Commercial and Government Entity code — identifies a legal entity at a specific location | DoD Defense Logistics Agency; SAM forwards your data automatically, free | 5 characters | Assigned during full registration; required for contract awards and DoD work |
| NCAGE | The NATO-issued CAGE equivalent for entities outside the U.S. | NATO Support and Procurement Agency | 5 characters | Foreign entities must obtain it BEFORE starting SAM registration |
| DUNS | Legacy proprietary identifier — retired for federal use April 4, 2022 | Dun & Bradstreet (private company) | 9 digits | Not needed. D&B/DUNS screenshots are explicitly unacceptable as SAM validation documents |
| TIN | Taxpayer Identification Number (EIN, or SSN for some sole proprietors), matched against IRS files during registration | IRS (EIN) / SSA (SSN) | 9 digits | Full registration for U.S. entities; the name+TIN must exactly match IRS records |
| MPIN | Marketing Partner ID Number — a credential that lets partner systems (e.g., SBA's) read your record | You create it yourself during registration | Self-chosen | Core Data step of full registration; later logins to partner applications |
The mental model
Think of it as four different questions the government asks about you: who are you (UEI — identity), where are you (CAGE — a specific legal entity at a specific location, which is why multi-site companies hold multiple CAGE codes), are your taxes real (TIN — matched to IRS records), and may this other system read your file (MPIN — a key you made up). DUNS answered the first question until 2022; it now answers none.
Practical consequences: a solicitation asking for your "UEI and CAGE" is asking for two things you already have if your SAM registration is active; nothing needs to be purchased, ever. If a form or portal still demands a DUNS number, it is out of date — point the requester at GSA's April 2022 transition notice.
FAQ
What replaced the DUNS number?
The Unique Entity ID (UEI), a 12-character identifier generated by SAM.gov itself. Federal systems switched on April 4, 2022.
Is a CAGE code the same as a UEI?
No. The UEI identifies your entity government-wide; the CAGE code (assigned by DLA) identifies a legal entity at a specific location and is required for contract awards. Full SAM registration gets you both automatically.
Does a CAGE code cost money?
No. SAM.gov sends your information to DLA and the CAGE code is assigned at no cost as part of registration.
What is an MPIN used for?
The Marketing Partner ID Number is a self-created credential entered during SAM registration that authorized partner systems use to access your record.