| 601 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Dec 2025 |
| 602 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 603 | United Oil Corporation | Denver, CO 80202-3813 | Oil & Gas Operator | Jan 2026 |
| 604 | Upland Operating, LLC | Dallas, TX 75226 | Oil & Gas Operator | Apr 2026 |
| 605 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Apr 2026 |
| 606 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Apr 2026 |
| 607 | Valpoint Operating, LLC | Amarillo, TX 79101 | Oil & Gas Operator | Apr 2026 |
| 608 | Van Orsdol Paul | Bristow, OK 74010 | Oil & Gas Operator | Feb 2026 |
| 609 | Veenker Resources Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2026 |
| 610 | Vess Oil Corporation | Dallas, TX 75201 | Oil & Gas Operator | Apr 2026 |
| 611 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2026 |
| 612 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 613 | Walker Keith F | Ardmore, OK 73401 | Oil & Gas Operator | Jan 2019 |
| 614 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2026 |
| 615 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2026 |
| 616 | Warren Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Jan 2016 |
| 617 | Warren Drilling Co | Dexter City, OH 45727 | Oil & Gas Operator | Dec 2025 |
| 618 | Washita Oil And Gas, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 619 | Weiser-Brown Operating Company | Magnolia, AR 71754 | Oil & Gas Operator | Apr 2026 |
| 620 | Western Farmers Electric Coop | Anadarko, OK 73005-0429 | Oil & Gas Operator | Apr 2012 |
| 621 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 622 | Wheeler Energy Co. | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 623 | Wheeler Energy, LLC | Tulsa, OK 74101 | Oil & Gas Operator | Apr 2026 |
| 624 | Whiteman Industries Inc | Oklahoma City, OK 73101 | Oil & Gas Operator | May 2025 |
| 625 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 626 | Wil-MC Oil Corporation The | Irving, TX 75015-2510 | Oil & Gas Operator | Mar 1999 |
| 627 | Will Energy Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jan 2026 |
| 628 | Wilshire Enterprises Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 629 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 630 | Woods Petroleum Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 631 | WR Oil & Gas LLC | Plano, TX 75024-3523 | Oil & Gas Operator | Feb 2026 |
| 632 | Wrather Jr J D | Beverly Hills, CA 90210-4724 | Oil & Gas Operator | Mar 1993 |
| 633 | Wynn-Crosby Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Jan 2026 |
| 634 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 635 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Feb 2026 |
| 636 | Young Tommy Oil Inc | Woodward, OK 73802-0893 | Oil & Gas Operator | Jan 2026 |
| 637 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 638 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 639 | Zeal Production Company | Sperry, OK 74073-4714 | Oil & Gas Operator | Feb 2026 |
| 640 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 641 | Zimtex Energy LLC | Perryton, TX 79070-5818 | Oil & Gas Operator | Nov 2017 |
| 642 | Zinke & Trumbo LTD | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2017 |