| 201 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 202 | White Butte Oil Operations, LLC | | Oil & Gas Operator | Aug 2025 |
| 203 | White Rock Oil & Gas, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 204 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 205 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 206 | Williston Industrial Supply Corporation | Williston, ND 58801 | Oil & Gas Operator | Mar 2012 |
| 207 | WPX Energy Williston, LLC | | Oil & Gas Operator | Aug 2025 |
| 208 | Wyoming Resources Corporation | Rapid City, SD 57702 | Oil & Gas Operator | Oct 2018 |
| 209 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 210 | Zavanna, LLC | | Oil & Gas Operator | Aug 2025 |
| 211 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Jul 2025 |
| 212 | Zenergy Operating Company, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2016 |
| 213 | Zinke & Trumbo, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2007 |