| 401 | Ameristate Exploration LLC | Austin, TX 78701 | Oil & Gas Operator | Nov 2009 |
| 402 | Ameritech Oil & Gas Corporation | Dallas, TX 75248 | Oil & Gas Operator | May 1996 |
| 403 | Amerril Energy LLC | Houston, TX 77042 | Oil & Gas Operator | Feb 2026 |
| 404 | Ames Financial, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 405 | Ames Oil | Cross Plains, TX 76443 | Oil & Gas Operator | Feb 2026 |
| 406 | Ames Oil Corporation Of Texas | Austin, TX 78720 | Oil & Gas Operator | Mar 2015 |
| 407 | Amexco, LLC | San Antonio, TX 78259 | Oil & Gas Operator | Feb 2026 |
| 408 | Amherst Energy Holdings, LLC | Highland VLG, TX 75077 | Oil Operator | Feb 2026 |
| 409 | Aminex USA, Inc. | Somerset, TX 78069 | Oil & Gas Operator | May 2018 |
| 410 | Amirmex Inc. | Denver, CO 80234 | Oil & Gas Operator | Feb 2026 |
| 411 | Amistad Energy Services, LLC | Katy, TX 77450 | Oil & Gas Operator | Oct 2017 |
| 412 | Amity Oil Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Aug 1977 |
| 413 | Ammo Energy, LLC | Oklahoma City, OK 73160 | Oil & Gas Operator | Feb 2009 |
| 414 | Ammonite Energy Texas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2003 |
| 415 | Amoco Production Co-Ratliff City | Ratliff City, OK 73081 | Oil Operator | May 1998 |
| 416 | Amoco Production Company | Houston, TX 77253 | Oil & Gas Operator | Jun 2015 |
| 417 | Ampak Oil Company | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 418 | Amplify Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 419 | Amron Petroleum, Inc. | Midland, TX 79708 | Oil & Gas Operator | Jan 1996 |
| 420 | Ams Energy Solutions LLP | Katy, TX 77493 | Oil Operator | Feb 2026 |
| 421 | Amt Resources, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 422 | Amtex Energy | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 423 | Amtex Energy, Inc. | Fort Worth, TX 76147 | Oil & Gas Operator | Feb 2026 |
| 424 | Amx Energy, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Feb 2026 |
| 425 | Ana-Tok Operating Co., Inc. | Pampa, TX 79066 | Oil & Gas Operator | Jun 2001 |
| 426 | Anadarko Austin Chalk Company | Houston, TX 77251 | Oil & Gas Operator | Feb 2006 |
| 427 | Anadarko E&P Company LP | Houston, TX 77251 | Oil & Gas Operator | Aug 2014 |
| 428 | Anadarko E&P Onshore LLC | Houston, TX 77046 | Oil & Gas Operator | Feb 2026 |
| 429 | Anadarko Minerals Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 430 | Anadarko Ogc Company | Houston, TX 77251 | Oil & Gas Operator | Dec 1998 |
| 431 | Anadarko Petroleum Co | Houston, TX 77227 | Oil & Gas Operator | Feb 1998 |
| 432 | Anadarko Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Dec 2025 |
| 433 | Ananda Energy Inc. | Pampa, TX 79065 | Oil & Gas Operator | Jan 2021 |
| 434 | Anaqua Oil & Gas, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2008 |
| 435 | Anatexas Offshore, Inc. | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 436 | Anathema, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Dec 1994 |
| 437 | Ancell Oil Co. | Wichita Falls, TX 76309 | Oil & Gas Operator | Dec 2018 |
| 438 | Anchor B Production, Inc. | Orla, TX 79770 | Oil & Gas Operator | Aug 2003 |
| 439 | Anchor Oil Company | Gruver, TX 79040 | Gas Operator | Feb 2026 |
| 440 | Anchor Operating Co. | Houston, TX 77055 | Oil & Gas Operator | Feb 2026 |
| 441 | Anchor Petroleum, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Jan 1996 |
| 442 | Anco Account | Wichita Falls, TX 76301 | Oil & Gas Operator | Oct 1995 |
| 443 | Andalucia Oil Company | San Antonio, TX 78258 | Oil Operator | Feb 2026 |
| 444 | Andco Oil | Pampa, TX 79066 | Oil & Gas Operator | Oct 1994 |
| 445 | Andector Exploration Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 446 | Anderman/Smith Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 1995 |
| 447 | Anderson Energy Corporation | Arvada, CO 80004 | Oil & Gas Operator | Feb 2026 |
| 448 | Anderson Oil & Gas Account | Wichita Falls, TX 76301 | Oil & Gas Operator | Nov 2013 |
| 449 | Anderson Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 2015 |
| 450 | Anderson Oil Corporation | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Nov 1999 |
| 451 | Anderson Oil LTD. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 452 | Anderson Petro-Equipment, Inc. | Montgomery, TX 77356 | Oil & Gas Operator | Feb 2026 |
| 453 | Anderson Producing, Inc. | Houston, TX 77057 | Oil & Gas Operator | Sep 2013 |
| 454 | Anderson Production | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 455 | Anderson, Carl T. | Wichita Falls, TX 76301 | Oil & Gas Operator | Feb 2014 |
| 456 | Anderson, Dorman | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 2012 |
| 457 | Anderson, E D | Cisco, TX 76437 | Oil & Gas Operator | Nov 2009 |
| 458 | Anderson, James K. Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 459 | Anderson, Roger W. Corp. | Clyde, TX 79510 | Oil & Gas Operator | Apr 2020 |
| 460 | Anderson, Steven C. | Victoria, TX 77902 | Gas Operator | Jun 2004 |
| 461 | Ando Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 1998 |
| 462 | Andrew Alan Exploration, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2017 |
| 463 | Andrew, Robert Oneal | Olney, TX 76374 | Oil & Gas Operator | Sep 1998 |
| 464 | Andrews & Corkran, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Feb 2000 |
| 465 | Andrews, B. C. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 466 | Andrus Resources Corporation | Houston, TX 77046 | Oil & Gas Operator | Oct 2002 |
| 467 | Anegada Resources | Kerrville, TX 78029 | Oil & Gas Operator | Jan 2002 |
| 468 | Anejo Production, LLC | Bangs, TX 76823 | Oil & Gas Operator | Feb 2026 |
| 469 | Angel Operating LLC | Metairie, LA 70033 | Oil Operator | Feb 2026 |
| 470 | Angelo, Ernest, Jr. | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 471 | Angle Oil Company | Hays, KS 67601 | Oil Operator | Sep 2002 |
| 472 | Anloc, LLC | Houston, TX 77024 | Oil & Gas Operator | Apr 2019 |
| 473 | Anr Production Company | Houston, TX 77046 | Oil & Gas Operator | Aug 2017 |
| 474 | Anschutz Exploration Corporation | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 475 | Anson Company | Oklahoma City, OK 73124 | Oil & Gas Operator | Apr 2018 |
| 476 | Antara Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 2004 |
| 477 | Antares Energy Company | Houston, TX 77010 | Oil & Gas Operator | Feb 2026 |
| 478 | Antares Oil Corp | Denver, CO 80202 | Oil & Gas Operator | Oct 2015 |
| 479 | Antelope Energy Company LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 480 | Antelope Energy Partners, LLC | Houston, TX 77027 | Oil & Gas Operator | Feb 2026 |
| 481 | Antelope Production Co. | Midland, TX 79701 | Oil & Gas Operator | Oct 1995 |
| 482 | Antelope Resources Inc | Billings, MT 59101 | Oil & Gas Operator | May 2017 |
| 483 | Antero Resources I, LP | Denver, CO 80202 | Oil & Gas Operator | Jun 2005 |
| 484 | Antero Resources II, LP | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 485 | Anthony Oil & Gas Co. | Shreveport, LA 71135 | Oil Operator | May 1993 |
| 486 | Anthony, Bob G. Inc. | Brookhaven, MS 39601 | Oil & Gas Operator | Feb 2026 |
| 487 | Anticline Energy, LLC | Three Rivers, MI 49093 | Oil & Gas Operator | Jul 2023 |
| 488 | Antilley, Joe | Abilene, TX 79602 | Oil & Gas Operator | Jan 2024 |
| 489 | Antle Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 490 | Antle, E. | Graham, TX 76450 | Oil & Gas Operator | Oct 1994 |
| 491 | Aoco Operating Company, L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Feb 2005 |
| 492 | Aoco Operating, L.P. | Houston, TX 77008 | Oil & Gas Operator | Mar 2008 |
| 493 | Aog, Inc. | Norman, OK 73070 | Oil & Gas Operator | Nov 2014 |
| 494 | Aogp, LLC | Turtle Lake, WI 54889 | Oil & Gas Operator | Sep 2019 |
| 495 | Aop Operating Corporation | Dallas, TX 75313 | Oil & Gas Operator | Aug 2003 |
| 496 | Ap Operating, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Feb 2026 |
| 497 | Apache Corporation | Houston, TX 77042 | Oil & Gas Operator | Feb 2026 |
| 498 | Apache Energy Resources Corp. | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 499 | Apache Oil Company | San Antonio, TX 78227 | Oil & Gas Operator | Jun 2023 |
| 500 | Apache Production Company | Holliday, TX 76366 | Oil & Gas Operator | Feb 2026 |