| Abbreviation | Definition |
|---|---|
| UTCX | Union Tank Car |
| UTCX | Union Tank Car Company |
| UTEU | Unienergy Technologies |
| UTHZ | TAL International Inc |
| UTHZ | Transamerica Leasing Incorporated |
| UTKU | Unitek Solvent Services |
| UTLU | Universal Truckload Services |
| UTLX | Union Tank Car |
| UTLX | Union Tank Car Company |
| UTLZ | United Trailer Leasing |
| UTLZ | United Trailer Leasing Company |
| UTPX | Suburban Propane LP |
| UTPX | Union Texas Petroleum Corporation |
| UTR | Union Transportation |
| UTTX | Trailer Train (TTX Corporation) |
| UTTX | TTX Company |
| UUAX | Up-Up and Away |
| UUAX | Up-Up and Away Incorporated |
| UUUZ | Uiterwyk Corporation |
| UYLU | United Yugoslav Lines |