The UEI is the federal government's primary identifier for contracting entities. It is a 12-character alphanumeric string assigned through SAM.gov when an entity registers or migrates from the legacy DUNS system. The UEI replaced the Dun and Bradstreet DUNS Number on April 4, 2022 — a change driven by the federal government's move away from a proprietary identifier owned by a private vendor toward one managed directly through SAM.gov.
UEI is required on every federal contract action, every entity registration record, and every reportable subcontract. Agencies use the UEI to track award activity in USAspending.gov, validate entity status during source selection, and link records across procurement systems. Unlike DUNS, the UEI is assigned at no cost and is generated by the government during entity registration rather than requested from a third party. Firms with an existing DUNS number had their UEI auto-assigned during the transition.
For small contractors, UEI registration is operational hygiene rather than strategy — but it is a hard prerequisite for award. A lapsed SAM.gov registration means a missing or invalid UEI, which means contracting officers cannot make award. Many small businesses have lost contracts they had won at the source-selection stage because their SAM registration lapsed during the award lag. Annual SAM renewal and active UEI maintenance are foundational discipline that every small federal contractor must run on a calendar.