| 501 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 502 | Trafalgar House Oil & Gas Inc | Houston, TX 77002-7346 | Oil & Gas Operator | Jan 1992 |
| 503 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 504 | Transok LLC | Oklahoma City, OK 73124-0300 | Oil & Gas Operator | Jul 2020 |
| 505 | Travis Peak Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 506 | Trepco Production Company Inc | Yukon, OK 73099 | Oil & Gas Operator | Feb 2026 |
| 507 | Trepel Petroleum Exploration & | | Oil & Gas Operator | Apr 2014 |
| 508 | Triad Energy, Inc. | Oklahoma City, OK 73105-1401 | Oil & Gas Operator | Feb 2026 |
| 509 | Tridon Oil Inc | Lafayette, LA 70505-2305 | Gas Operator | Dec 2013 |
| 510 | Trinity Operating (Usg), LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 511 | Tripower Resources LLC | Ardmore, OK 73402 | Oil & Gas Operator | Apr 2026 |
| 512 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 513 | Trout Disposal Well Inc | Hammon, OK 73650 | Oil & Gas Operator | Jan 2025 |
| 514 | Troy Energy Operating LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2026 |
| 515 | TRP-Ok Properties LLC | Norman, OK 73072 | Oil & Gas Operator | Feb 2026 |
| 516 | Truckers Disposal Inc | Skiatook, OK 74070 | Oil & Gas Operator | Feb 2026 |
| 517 | Truevine Gas Company | Ada, OK 74821-1422 | Oil & Gas Operator | Jan 2026 |
| 518 | Tucker Ron & Co | Norman, OK 73069-8511 | Gas Operator | Sep 2017 |
| 519 | Turntable Energy Inc | Ponca City, OK 74604 | Oil & Gas Operator | Oct 2025 |
| 520 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 521 | Txok Energy Resources Company | Tulsa, OK 74172-0140 | Oil & Gas Operator | Feb 2017 |
| 522 | Tytan Operating Company LLC | Edmond, OK 73083-3794 | Oil & Gas Operator | May 2016 |
| 523 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 524 | Unicon Producing Company | Houston, TX 75252 | Gas Operator | Mar 1994 |
| 525 | Union Texas Petroleum Corp | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 526 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Dec 2025 |
| 527 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2026 |
| 528 | United Energy Operating, LLC | Edmond, OK 73083 | Oil & Gas Operator | Apr 2026 |
| 529 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Apr 2026 |
| 530 | Vanguard Permian, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 531 | Vantage Point Operating Co. | Houston, TX 77057 | Oil & Gas Operator | Dec 2014 |
| 532 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Dec 2025 |
| 533 | Vectra CBM LLC | Littleton, CO 80128-4557 | Gas Operator | Jan 2014 |
| 534 | Vega Energy Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2015 |
| 535 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2026 |
| 536 | W F D Oil Corp. | Edmond, OK 73012 | Oil & Gas Operator | Jan 2026 |
| 537 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2026 |
| 538 | Ward Oil Company An Okla Corp | McAlester, OK 74501 | Oil & Gas Operator | Feb 1993 |
| 539 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2026 |
| 540 | Waterbridge Arkoma Operating LLC | Houston, TX 77056 | Oil Operator | Jan 2026 |
| 541 | Weatherly Nell M Estate | Ada, OK 74821-0669 | Oil & Gas Operator | Feb 1997 |
| 542 | Wentworth Operating Company | Oklahoma City, OK 73162-1863 | Oil & Gas Operator | Feb 2026 |
| 543 | Wheeler Energy Co. | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 544 | Wheeler Energy, LLC | Tulsa, OK 74101 | Oil & Gas Operator | Apr 2026 |
| 545 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 546 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 547 | Whitmar Natural Resources Co | Tulsa, OK 74136-9998 | Oil & Gas Operator | Jun 2004 |
| 548 | Whitmar Operating Company | Tulsa, OK 74103-3515 | Oil & Gas Operator | Apr 2009 |
| 549 | Wilcox Pipe & Supply Co | Oklahoma City, OK 73189 | Oil & Gas Operator | May 2006 |
| 550 | Wild Outdoors Oil LLC | Duncan, OK 73533 | Oil & Gas Operator | Feb 2026 |
| 551 | Williams Reid Oil Co | Dallas, TX 75234 | Oil & Gas Operator | Jan 2026 |
| 552 | Williford Energy Company | Tulsa, OK 74135 | Oil & Gas Operator | Apr 2026 |
| 553 | Wilshire Enterprises Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 554 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 555 | Wohlford Properties Inc | Barling, AR 72923 | Gas Operator | Apr 2022 |
| 556 | Wolf Howard Lee | Burneyville, OK 73430-9617 | Oil & Gas Operator | Jun 2000 |
| 557 | Worldwide Energy Corporation | Freer, TX 78357 | Oil & Gas Operator | Jan 1997 |
| 558 | WPX Energy Mid-Continent Co | Oklahoma City, OK 73102-5010 | Oil & Gas Operator | Apr 2016 |
| 559 | Wynn-Crosby Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Jan 2026 |
| 560 | Wytex Production Corporation | Fort Smith, AR 72903 | Oil & Gas Operator | Jan 2026 |
| 561 | Xae Corporation | Norman, OK 73072 | Oil & Gas Operator | Apr 2021 |
| 562 | Xanadu Exploration Company | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2026 |
| 563 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 564 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Feb 2026 |
| 565 | Yarberry Oil Company | Wichita Falls, TX 76308-5120 | Oil & Gas Operator | Apr 2015 |
| 566 | Z G Exploration Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2005 |
| 567 | Zeiders Bros. Oil & Gas Company, L.L.C. | Edmond, OK 73003 | Oil & Gas Operator | Jan 2026 |
| 568 | Zenith Oil & Gas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2026 |
| 569 | Zinke & Trumbo LTD | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2017 |
| 570 | ZZ Energy LLC | Norman, OK 73070 | Gas Operator | Jan 2026 |