| Abbreviation | Definition |
|---|---|
| UMMC | Ural Mining and Metallurgical Company |
| UMN | United Media Network |
| UMP | Underground Music Productions |
| UMP | United Midwest Promotions |
| UMP | United Midwestern Promoters |
| UMPA | University Medical Practice Associates |
| UMR | Underground Music Revolution |
| UMR | Underground Musicians Resource |
| UMRG | Universal Motown Records Group |
| UMT | United Management Technologies |
| UMT | Universal Microwave Technology, Inc. |
| UMTC | Urban Mass Transit Company Limited |
| UMV | Uddevalla Mekaniska Verkstad |
| UMVD | Universal Music and Video Distribution Corporation |
| UMW | United Mine Workers Union |
| UMXU | CSX Intermodal Inc |
| UMXU | Union Pacific Railroad Company |
| UMZ | Ulbinsk Metallurgical Combine |
| UNAC | United Nations Ammo Company |
| UNC | United Nuclear Corporation |