| Abbreviation | Definition |
|---|---|
| UCOMP | United GlobalCom, Inc. Preferred |
| UCOMP | United GlobalCom, Incorporated Preferred (de-listed) |
| UCOMP | United GlobalCom, Incorporated Preferred (de-listed) |
| UCOR | Urocor, Inc. |
| UCOR | Urocor, Incorporated (de-listed) |
| UCOR | Urocor, Incorporated (de-listed) |
| UCTN | C T N Media Group, Inc. |
| UCTN | CTN Media Group, Incorporated (de-listed) |
| UCTN | CTN Media Group, Incorporated (de-listed) |
| UDCN | UDC Homes, Inc. |
| UDCNQ | U D C Homes, Inc. |
| UDCNQ | UDC Homes, Incorporated, in bankruptcy (de-listed) |
| UDCNQ | UDC Homes, Incorporated, in bankruptcy (de-listed) |
| UDHI | Union Dental Holdings, Inc. |
| UDIG | U S A Digital, Inc. |
| UDIG | USA Digital, Incorporated (de-listed) |
| UDIG | USA Digital, Incorporated (de-listed) |
| UDWK | U S Dataworks |
| UDYN | Unidyne Corporation |
| UEIC | Universal Electronics, Inc. |