| 401 | Western Field Exploration, Inc. | Dilley, TX 78017 | Oil & Gas Operator | Jul 2025 |
| 402 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Jul 2025 |
| 403 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 404 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 405 | Williams, Clayton Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Jul 2025 |
| 406 | Williams, Clayton Energy, L.L.C | Midland, TX 79705 | Oil & Gas Operator | May 1993 |
| 407 | Williams, Clayton W., Jr., Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 408 | Windsor Exploration Company | Dallas, TX 75204 | Oil & Gas Operator | Jan 1994 |
| 409 | Wolco Energy, Inc. | Dallas, TX 75220 | Oil & Gas Operator | May 1997 |
| 410 | World Energy Corporation | Laredo, TX 78041 | Oil & Gas Operator | Aug 2003 |
| 411 | Wright Brothers Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Jul 2025 |
| 412 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 413 | Yarborough Oil & Gas L.P. | Midland, TX 79701 | Oil & Gas Operator | Oct 2000 |
| 414 | Young, Clint Inc. | Graham, TX 76450 | Oil & Gas Operator | Jul 2025 |
| 415 | Young, John H., Inc. | Houston, TX 77027 | Oil & Gas Operator | Jul 2025 |
| 416 | Zaf Oil | San Antonio, TX 78230 | Oil & Gas Operator | Aug 2002 |
| 417 | Zaza Energy, LLC | Houston, TX 77010 | Oil & Gas Operator | Jul 2025 |