| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 2 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 3 | Union Texas Petroleum Corp. | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 4 | Union Valley Petroleum Corporation | Enid, OK 73701 | Oil & Gas Operator | Feb 2024 |
| 5 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 6 | United Production Company LLC | Edmond, OK 73083-5348 | Oil & Gas Operator | Feb 2024 |
| 7 | United States Trading & Trans | Dallas, TX 75380-3342 | Oil & Gas Operator | Dec 1994 |
| 8 | Universal Fuels Company | Oil & Gas Operator | Oct 1993 |