| 601 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 602 | Western Sky Oil & Gas | Abilene, TX 79604 | Oil & Gas Operator | Aug 2003 |
| 603 | Westico Energy Co. | Abilene, TX 79605 | Oil & Gas Operator | Nov 2004 |
| 604 | Westlake Energy Consultants Corp | Thousand Oaks, CA 91362 | Oil & Gas Operator | Aug 2003 |
| 605 | Westwood Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2013 |
| 606 | White, Frank | Abilene, TX 79604 | Oil & Gas Operator | Feb 2026 |
| 607 | White, Oscar | Tuscola, TX 79562 | Oil & Gas Operator | Feb 2026 |
| 608 | Whitehall Operating Inc. | Houston, TX 77040 | Oil & Gas Operator | Nov 1994 |
| 609 | Whiteside, H. W. | Abilene, TX 79604 | Oil & Gas Operator | Nov 1998 |
| 610 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 611 | Whitt Oil & Gas, Inc. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 612 | Wilbanks, Bruce A. | Midland, TX 79701 | Oil & Gas Operator | Aug 1996 |
| 613 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 614 | Wilcox Oil Company | Rule, TX 79547 | Oil & Gas Operator | Aug 2008 |
| 615 | Wilcox Petroleum Operating LLC. | Rule, TX 79547 | Oil & Gas Operator | Feb 2026 |
| 616 | Willow Creek Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2009 |
| 617 | Winchester Energy, LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 618 | Winco Oil Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 619 | Windham Resources | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 620 | Windham Resources, Inc. | Tuscola, TX 79562 | Oil & Gas Operator | Feb 2004 |
| 621 | Window Operating Co., The | Coleman, TX 76834 | Oil & Gas Operator | Feb 2026 |
| 622 | Woodbine Petroleum, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Aug 2003 |
| 623 | Xtreme Operating Company LLC | Flower Mound, TX 75022 | Oil Operator | Feb 2026 |
| 624 | Young, L. M. | Brownwood, TX 76804 | Oil & Gas Operator | Aug 2003 |