| 601 | W & T Offshore, L.L.C. | Houston, TX 77046 | Gas Operator | Jan 1999 |
| 602 | Wagner & Brown, LTD. | Midland, TX 79702 | Oil & Gas Operator | Aug 2014 |
| 603 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2025 |
| 604 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 605 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 606 | Walkabout Operating, LLC | Lubbock, TX 79424 | Oil & Gas Operator | Jul 2025 |
| 607 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Jul 2025 |
| 608 | Warwick Oil & Gas, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 1993 |
| 609 | Watco Energy, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Apr 1996 |
| 610 | West Mountain Operating Co, Inc. | Longview, TX 75604 | Oil & Gas Operator | Feb 2019 |
| 611 | Whitaker Properties, L. P. | Carthage, TX 75633 | Oil & Gas Operator | Sep 1997 |
| 612 | White Pine Petroleum Corporation | Wichita, KS 67202 | Oil & Gas Operator | Dec 2019 |
| 613 | White Stride LLC | Piedmont, OK 73078 | Oil & Gas Operator | Jul 2025 |
| 614 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 615 | Wilco Properties, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Jan 2004 |
| 616 | Wilcox Operating Corporation | Shreveport, LA 71115 | Oil & Gas Operator | Jul 2025 |
| 617 | Wildhorse Resources MNGT Co, LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | May 2019 |
| 618 | Wildhorse Resources, LLC | Houston, TX 77279 | Oil & Gas Operator | Feb 2015 |
| 619 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jul 2025 |
| 620 | Williamson Oil & Gas, Inc. | Shreveport, LA 71166 | Oil & Gas Operator | Dec 2024 |
| 621 | Willow Springs Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Sep 1999 |
| 622 | Wilson Hydrocarbon Inc. | Houston, TX 77066 | Oil & Gas Operator | Jul 2025 |
| 623 | Wimco | Dallas, TX 75229 | Oil & Gas Operator | Jul 2008 |
| 624 | Winchester Production Co., LTD. | Shreveport, LA 71129 | Oil & Gas Operator | Sep 2008 |
| 625 | Winchester Production Company | Shreveport, LA 71129 | Oil & Gas Operator | Nov 2008 |
| 626 | Wind River Resources Inc | Tulsa, OK 74136-6381 | Oil & Gas Operator | Jun 2010 |
| 627 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 628 | WJ South Waskom #1, LLC | Dallas, TX 75205 | Oil Operator | Jul 2025 |
| 629 | Wnu Energy LLC | Pinedale, WY 82941 | Oil & Gas Operator | May 2025 |
| 630 | Woodbine Production Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |
| 631 | Wynn-Crosby Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 632 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 633 | Young, Clint Inc. | Graham, TX 76450 | Oil & Gas Operator | Jul 2025 |
| 634 | Zadeck Energy Group | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2011 |
| 635 | Zivney Energy | White Oak, TX 75693 | Oil & Gas Operator | Jul 2025 |