| 501 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 502 | Western Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 503 | Western Reserves Corporation | Abilene, TX 79608 | Oil & Gas Operator | Jan 2008 |
| 504 | Westoil LLC | Austin, TX 78747 | Oil & Gas Operator | Feb 2026 |
| 505 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 506 | Westridge Oil & Gas Properties | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 507 | Wheat, Buck Resources, Inc. | Eastland, TX 76448 | Oil & Gas Operator | Dec 2009 |
| 508 | White Heart, Inc. | Georgetown, TX 78628 | Gas Operator | Jun 1996 |
| 509 | White Knight Production LLC | Lafayette, LA 70505 | Oil & Gas Operator | Feb 2024 |
| 510 | Whitehead Prod. Co., Inc. | Humble, TX 77338 | Oil & Gas Operator | Dec 2025 |
| 511 | Whittier Operating Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2007 |
| 512 | Williams Prod. Gulf Coast, L.P. | Benbrook, TX 76126 | Oil & Gas Operator | Jan 2012 |
| 513 | Willowbend Investments, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 514 | Wilson Exploration Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 1996 |
| 515 | Winchester Oil & Gas LLC | Rockdale, TX 76567 | Oil Operator | Feb 2026 |
| 516 | Winfield Operating Company | Dallas, TX 75214 | Oil & Gas Operator | Feb 2026 |
| 517 | Wise Exploration | Perrin, TX 76486 | Oil & Gas Operator | Feb 2026 |
| 518 | Wise Production Company | Bowie, TX 76230 | Oil & Gas Operator | Feb 2026 |
| 519 | Wise Well Service | Bowie, TX 76230 | Oil & Gas Operator | Jul 2017 |
| 520 | World Producers, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1994 |
| 521 | WPX Energy Gulf Coast, LP | Benbrook, TX 76126 | Oil & Gas Operator | May 2012 |
| 522 | Wy Woodland Operating, LLC | Covington, TX 76636 | Oil & Gas Operator | Feb 2026 |
| 523 | Xplore Operating, LLC | Arlington, TX 76001 | Oil & Gas Operator | Feb 2026 |
| 524 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 525 | Young Marshall R Oil Co | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2011 |
| 526 | Young Resources, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1999 |
| 527 | Young, L. M. | Brownwood, TX 76804 | Oil & Gas Operator | Aug 2003 |
| 528 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | Feb 2026 |