| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | Underwood, D. W. | Eldorado, TX 76936 | Oil & Gas Operator | Nov 1997 |
| 2 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 3 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 4 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 5 | Upstream Properties, LLC | Southlake, TX 76092 | Oil & Gas Operator | Feb 2026 |