| Abbreviation | Definition |
|---|---|
| UDI | Universal Direct Group, PLC |
| UDL | Unified Design Labs |
| UDMC | United Defense Manufacturing Corporation |
| UDN | Uganda Debt Network |
| UDN | Universal Domain Network |
| UDR | The UD Registry, Inc. |
| UDR | United Dance Resource |
| UDR | Universal Drill Rigs |
| UDS | Universal Documentation Systems |
| UDT | United Dominions Trust |
| UDTC | Upper Deck Trading Cards |
| UDU | Umuaka Development Union |
| UDV | Ulric de Varens |
| UDW | Unternehmensberatung der Wirtschaft, GmbH |
| UDWA | Unterstützungskasse der Wohnungswirtschaft, e. V. |
| UE&C | United Engineers & Constructors, Inc. |
| UEA | United Energy Associates, Inc. |
| UEA | United Equipment Accessories, Inc. |
| UEB | UranErzbergBau, GmbH |
| UEBV | Ulstein Equipment B.V. |