| 401 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Jun 2026 |
| 402 | Texas Tea Of Colorado LLC Dba Texas Tea LLC | | Oil & Gas Operator | Jun 2021 |
| 403 | Thomas L Spring LLC | | Gas Operator | Feb 2026 |
| 404 | Tidal Wave Energy, Inc. | New Castle, PA 16105 | Oil & Gas Operator | Jun 2022 |
| 405 | Tigges Oil LLC | | Oil & Gas Operator | Dec 2022 |
| 406 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Dec 2025 |
| 407 | Timka Resources, LTD | | Oil & Gas Operator | Mar 2026 |
| 408 | Tindall Operating Company | Englewood, CO 80112 | Oil & Gas Operator | Jan 2025 |
| 409 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 410 | Tom Fenno Production LLC | | Oil Operator | Apr 2017 |
| 411 | Top Operating Company | | Oil & Gas Operator | Jul 2022 |
| 412 | Trend Exploration Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 413 | Trinity Energy Corp | Gibsonia, PA 15044-9106 | Oil & Gas Operator | Dec 2007 |
| 414 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Apr 2026 |
| 415 | Tudex Petroleum Inc | | Oil & Gas Operator | Sep 2019 |
| 416 | Twin Arrow Inc | Rangely, CO 81648 | Oil & Gas Operator | Sep 2009 |
| 417 | Tyler Rockies Exploration LTD | Tyler, TX 75710-0119 | Oil & Gas Operator | Dec 2025 |
| 418 | Umad LLC | | Oil & Gas Operator | Feb 2010 |
| 419 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Dec 2010 |
| 420 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Jun 2026 |
| 421 | United States Exploration, Inc. | Denver, CO 80802 | Oil & Gas Operator | Apr 2007 |
| 422 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2026 |
| 423 | Vecta Oil & Gas LTD | Dallas, TX 75235 | Oil & Gas Operator | Dec 2025 |
| 424 | Verdad Resources LLC | | Oil & Gas Operator | Feb 2026 |
| 425 | Vision Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 426 | Vista Operating, Inc. | | Oil & Gas Operator | Dec 2014 |
| 427 | Visual Optics Inc | | Oil Operator | Dec 2012 |
| 428 | Vitruvian Exploration LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2016 |
| 429 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Jun 2026 |
| 430 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | Jun 2026 |
| 431 | Ward & Son* Alfred | | Oil & Gas Operator | Jul 2021 |
| 432 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Feb 2026 |
| 433 | Wavetech Helium Inc | | Gas Operator | Feb 2026 |
| 434 | Wellington Operating Company | | Oil & Gas Operator | Mar 2026 |
| 435 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Apr 2026 |
| 436 | Wesco Operating Inc | Casper, WY 82602 | Oil & Gas Operator | Apr 2026 |
| 437 | West Texas Operating Co LLC D/B/A Xtreme Energy Co | Victoria, TX 77902-2326 | Oil & Gas Operator | Jan 2026 |
| 438 | Western Gas Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 439 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 440 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Jan 2026 |
| 441 | Westgate Oil Company, Inc. | Eureka, KS 67045 | Oil & Gas Operator | Mar 2026 |
| 442 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Mar 2026 |
| 443 | Wexpro Development Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Feb 2026 |
| 444 | Wiepking-Fullerton Energy LLC | | Oil & Gas Operator | Feb 2026 |
| 445 | Williford Energy Company | Tulsa, OK 74135 | Oil & Gas Operator | Jun 2026 |
| 446 | Williford Resources LLC | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2026 |
| 447 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 448 | Wise* Wayne L | | Oil & Gas Operator | Dec 2023 |
| 449 | Wme Yates LLC | | Gas Operator | Dec 2023 |
| 450 | Wold Oil Properties Inc | Denver, CO 80203 | Oil & Gas Operator | Feb 2018 |
| 451 | Wolverine Resources LLC | | Oil & Gas Operator | Jan 2024 |
| 452 | Woodard* Sandra K | | Oil Operator | Jul 2024 |
| 453 | Woodbury Resources LLC | | Oil & Gas Operator | Apr 2024 |
| 454 | WPX Energy Rocky Mountain LLC | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 455 | Wy Woodland Operating, LLC | Covington, TX 76636 | Oil & Gas Operator | Jun 2026 |
| 456 | Wyman* Louis M Dba Wyman Inc | | Oil & Gas Operator | Feb 2026 |
| 457 | Wynn-Crosby Operating, LTD. | Dallas, TX 75201 | Oil & Gas Operator | Jun 2026 |
| 458 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Jun 2026 |
| 459 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Jun 2026 |