Unique Entity Identifier (UEI) / DUNS Number

How It Works

Every organization receiving federal funding must have a Unique Entity Identifier (UEI), a 12-character alphanumeric code assigned through SAM.gov registration. The UEI was introduced on April 4, 2022 as part of GSA's Integrated Award Environment transition away from the Data Universal Numbering System (DUNS) Number, a 9-digit proprietary identifier owned by Dun & Bradstreet that the federal government had licensed since 1978. The switch eliminated an annual licensing fee of roughly $18-25 million and put entity identification under direct federal control, addressing years of GAO and IG concerns that a commercial vendor should not hold the keys to federal contractor identification. During a transition period (April 2022 to September 2022), systems displayed both UEI and DUNS, but legacy DUNS is now deprecated and new registrations receive only a UEI. Historical award records on USASpending.gov still display DUNS for transactions before April 2022, which complicates longitudinal analysis, a contractor's UEI and legacy DUNS may not always cleanly cross-reference if name, address, or parent-subsidiary relationships changed over time. UEIs are publicly searchable on SAM.gov and are the recommended primary key for identifying a contractor across federal systems, though TaxDollarData also tracks CAGE codes and normalized recipient names to handle legacy data and cases where the same corporate family operates multiple registered entities with different UEIs (common for joint ventures, wholly-owned subsidiaries, and M&A transitions). The UEI is 12 alphanumeric characters assigned algorithmically with a checksum digit; it is not meaningful on its own but serves purely as a unique key. When a company registers a new legal entity (new state of incorporation, new TIN, merger into a new parent), it receives a new UEI, which can fragment a contractor's spending history across multiple identifiers and is a common source of analytical confusion.

Related Terms

• SAM.gov (System for Award Management), The federal government's central registration database for entities doing business with the government, required for receiving contracts, grants, or other awards.
• CAGE Code (Commercial and Government Entity), A 5-character alphanumeric identifier assigned by the Defense Logistics Agency to companies that do business with the federal government, used for contract administration and cataloging.
• NAICS Code, The North American Industry Classification System code, a 6-digit number that classifies a business by the type of economic activity it performs, used to determine small business size standards.