| 201 | Union Pacific Austin Chalk Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 202 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 203 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 204 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Sep 2024 |
| 205 | Usfg Oil & Gas, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Dec 2005 |
| 206 | Vega Operating Company | Eaton, CO 80615 | Oil & Gas Operator | Dec 2024 |
| 207 | Verdun Oil & Gas LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2024 |
| 208 | Watt Energy, LLC | Port Barre, LA 70577 | Oil & Gas Operator | Dec 2024 |
| 209 | WCS Oil & Gas Corporation | Dallas, TX 75209 | Oil & Gas Operator | Aug 2021 |
| 210 | Weber Energy Corporation | Dallas, TX 75219 | Oil & Gas Operator | Feb 2017 |
| 211 | Westpark Petroleum, Inc. | Austin, TX 78755 | Oil & Gas Operator | Dec 2024 |
| 212 | Wildfire Energy Operating LLC | Houston, TX 77224 | Oil & Gas Operator | Dec 2024 |
| 213 | Wildhorse Resources MNGT Co, LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | May 2019 |
| 214 | Williams, Clayton Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Dec 2024 |
| 215 | Williams, Clayton Energy, L.L.C | Midland, TX 79705 | Oil & Gas Operator | May 1993 |
| 216 | Williams, Clayton W., Jr., Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 217 | Winn Exploration Co., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2024 |
| 218 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | Dec 2024 |