| 401 | Adamson Exploration Co. | Kilgore, TX 75662 | Oil Operator | May 2026 |
| 402 | Adamson Exploration Corporation | Kilgore, TX 75662 | Oil & Gas Operator | Mar 2008 |
| 403 | Adamson, Michael A. | Sapulpa, OK 74066 | Oil Operator | Oct 2015 |
| 404 | Adco LTD. | | Oil & Gas Operator | Dec 1983 |
| 405 | Adco Producing Co. | | Oil & Gas Operator | Mar 1989 |
| 406 | Adcock, Carol | Ozona, TX 76943 | Oil & Gas Operator | May 2026 |
| 407 | Adcock, Leroy | Ozona, TX 76943 | Oil & Gas Operator | Jun 2009 |
| 408 | Add Energy Co | Butler, PA 16002-0471 | Gas Operator | Dec 2020 |
| 409 | Addax Operating, LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2026 |
| 410 | Addie, James & John Thornton | | Oil & Gas Operator | Dec 2024 |
| 411 | Addington Exploration, LLC | | Oil & Gas Operator | Dec 2006 |
| 412 | Addis Family Tru | | Oil Operator | Apr 1992 |
| 413 | Addis, Icer Estate Of | Wichita, KS 67208 | Gas Operator | Jun 2015 |
| 414 | Addison - Graves, L.L.C. | Archer City, TX 76351 | Oil Operator | May 2026 |
| 415 | Addison Oil, LLC | Addison, TX 75001 | Oil & Gas Operator | Mar 2013 |
| 416 | Addison Resources Inc. | | Oil & Gas Operator | Jul 1998 |
| 417 | Addison, Kenneth | Archer City, TX 76351 | Oil & Gas Operator | Dec 2017 |
| 418 | Adeco Energy Corporation | Norman, OK 73071 | Oil & Gas Operator | Apr 2014 |
| 419 | Adeco, Inc. | Hays, KS 67601 | Oil Operator | Jan 2026 |
| 420 | Adela Oil | Seguin, TX 78155 | Oil & Gas Operator | Jun 2000 |
| 421 | Adelaide Energy LLC | FT Morgan, CO 80701 | Oil Operator | Jan 2026 |
| 422 | Adelaide Energy, Inc. | | Oil Operator | May 2022 |
| 423 | Adenryen, LTD. Co. | Richardson, TX 75082 | Oil Operator | May 2026 |
| 424 | Adexco Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2024 |
| 425 | Adgo Resources LLC | Midland, TX 79701 | Oil & Gas Operator | Nov 2018 |
| 426 | Adkins Jim | Weleetka, OK 74880-8057 | Oil & Gas Operator | Apr 2020 |
| 427 | Adkins Production Co. | | Oil Operator | Aug 2015 |
| 428 | Adkins, Franklin | Ona, WV 25545-0070 | Oil & Gas Operator | Dec 2021 |
| 429 | Adkins, Michael H. | Austin, TX 78747 | Oil & Gas Operator | May 2026 |
| 430 | Adkins, R. L. Corp. | Lubbock, TX 79408 | Oil & Gas Operator | Jun 2013 |
| 431 | Adkins, Russell M & Mary | Louisa, KY 41230 | Oil Operator | Dec 2019 |
| 432 | Adkins, Teddy D. | | Oil & Gas Operator | Dec 2020 |
| 433 | Adler Energy LC | | Oil Operator | May 2017 |
| 434 | Adm Industrial O | | Oil Operator | Nov 1989 |
| 435 | Admiral Bay (USA) Inc. | Centennial, CO 80112 | Gas Operator | Jun 2011 |
| 436 | Admiral Permian Operating LLC | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 437 | Admiral Resource Inc | Broken Arrow, OK 74012 | Oil & Gas Operator | Apr 2020 |
| 438 | Adobe Energy Company | | Oil & Gas Operator | Aug 2010 |
| 439 | Adobe Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Nov 2004 |
| 440 | Adobe Oil & Gas Corporation | Midland, TX 79701 | Oil & Gas Operator | Jan 1993 |
| 441 | Adobe Operating Company | Pampa, TX 79066 | Oil & Gas Operator | May 2026 |
| 442 | Adobe Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Aug 2002 |
| 443 | Adparo LLC | Oklahoma City, OK 73102-4803 | Oil & Gas Operator | Mar 2026 |
| 444 | Adr Operating, Inc. | Independence, KS 67301 | Oil & Gas Operator | Sep 2013 |
| 445 | Adrian Beachel | Henryetta, OK 74437 | Oil & Gas Operator | Feb 2026 |
| 446 | Ads | Caldwell, TX 77836 | Oil & Gas Operator | Dec 2010 |
| 447 | Ads Oil & Gas, Inc. | Caldwell, TX 77836 | Oil & Gas Operator | May 2026 |
| 448 | Advance Energy Partners Hat Mesa, LLC | Dallas, TX 75240 | Oil & Gas Operator | Jul 2023 |
| 449 | Advance Exploration | Abilene, TX 79601 | Oil & Gas Operator | May 2026 |
| 450 | Advance Oil Corporation | Kiefer, OK 74041-4105 | Oil & Gas Operator | Mar 2026 |
| 451 | Advanced Petro Corp | Hamburg, NY 14075-5003 | Oil & Gas Operator | Dec 1992 |
| 452 | Advanced Petroleum Enhancement, Inc | Madisonville, KY 42431 | Oil & Gas Operator | Dec 2021 |
| 453 | Advanced Recovery Services Co | Denver, CO 80265 | Oil & Gas Operator | Apr 2007 |
| 454 | Advanced Wireless Communications, L.L.C. | Farmington, NM 87401 | Oil & Gas Operator | Mar 2026 |
| 455 | Advantage Oil & Gas, Inc. | Pinehurst, TX 77362 | Oil & Gas Operator | May 2026 |
| 456 | Advantage Resour | | Oil & Gas Operator | May 1994 |
| 457 | Advantage Resources Inc | Broomfield, CO 80020 | Oil & Gas Operator | Jan 2026 |
| 458 | Advantagewon Oil, Us, Corp. | Batson, TX 77519 | Oil Operator | Dec 2019 |
| 459 | Advent Oil & Operating Inc | Gulfport, MS 39506-7115 | Oil & Gas Operator | Nov 2014 |
| 460 | Adventure Expl Partners II, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2014 |
| 461 | Adventure Exploration Partners, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2011 |
| 462 | Adventure Exploration PTRS, LLC | Midland, TX 79702 | Oil & Gas Operator | Aug 2012 |
| 463 | Adventure Operating Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Jan 2021 |
| 464 | Adventure Properties Inc | Ada, OK 74820 | Oil & Gas Operator | Mar 2026 |
| 465 | Aec Operating Company | Roswell, NM 88202 | Oil & Gas Operator | Sep 2006 |
| 466 | Aed Development Inc | Columbus, OH 43220 | Oil & Gas Operator | Dec 1995 |
| 467 | Aeg Operating, LLC | Austin, TX 78746 | Oil Operator | Jun 2012 |
| 468 | Aegean Oil & Gas Inc | Brunswick, OH 44212 | Oil & Gas Operator | Dec 1993 |
| 469 | Aegean Petroleum | | Oil Operator | Mar 1982 |
| 470 | Aegis Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Sep 1998 |
| 471 | Aegis Fluids Management, LLC | Plano, TX 75093 | Oil & Gas Operator | May 2026 |
| 472 | Aei Corporation-Oklahoma | Oklahoma City, OK 73101-1945 | Oil & Gas Operator | Sep 2014 |
| 473 | Aei Production Company | Edmond, OK 73083 | Oil & Gas Operator | Mar 2014 |
| 474 | Aeon Energy Corp. | | Oil & Gas Operator | Apr 2026 |
| 475 | Aeon Energy Inc | Claremore, OK 74017 | Oil Operator | May 2009 |
| 476 | Aeon Operating, Inc. | Fate, TX 75132 | Oil & Gas Operator | May 2026 |
| 477 | Aera Energy LLC | | Oil & Gas Operator | Mar 2026 |
| 478 | Aerie Energy | Cedar Creek, TX 78612 | Oil Operator | May 2026 |
| 479 | Aesir Energy | | Oil Operator | Oct 2007 |
| 480 | Aeternum Energy, LLC | Tyler, TX 75713 | Oil & Gas Operator | May 2026 |
| 481 | Aethon Energy Operating LLC | Dallas, TX 75251 | Oil & Gas Operator | May 2026 |
| 482 | Aethon I LP | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 483 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Mar 2026 |
| 484 | Af Operating, LLC | Tuscaloosa, AL 35404 | Oil Operator | Sep 2012 |
| 485 | Afco Energy Prod Co | Indiana, PA 15701-0538 | Oil & Gas Operator | Dec 2019 |
| 486 | Afe Management Limited | Concord, Ontario, L4K 4G4 | Oil & Gas Operator | Sep 1987 |
| 487 | Afe Oil & Gas Consultants | Addison, TX 75001 | Gas Operator | Jan 2003 |
| 488 | Affiliated Holdings, Inc. | | Oil Operator | Dec 2010 |
| 489 | Afg Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 490 | Afo LLC | Velma, OK 73491 | Oil & Gas Operator | Dec 2024 |
| 491 | Afoc, LLC | Midland, TX 79710 | Oil & Gas Operator | May 2026 |
| 492 | Agape Energy Inc. | San Antonio, TX 78280 | Oil Operator | May 2026 |
| 493 | Agape Inc | Broken Arrow, OK 74011-4256 | Oil & Gas Operator | Feb 2026 |
| 494 | Agape Service Incorporated | Denver, CO 80201 | Gas Operator | Jan 2026 |
| 495 | Agar & Agar Inc | Norman, OK 73070 | Oil & Gas Operator | Oct 1996 |
| 496 | Agate Petroleum, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2015 |
| 497 | Agave Energy Inc | Stigler, OK 74462 | Oil & Gas Operator | Feb 2026 |
| 498 | Agave Operating Company, Inc. | Holliday, TX 76366 | Oil Operator | May 2026 |
| 499 | Agent Oil Corporation | Bison, OK 73720-0116 | Oil & Gas Operator | Mar 2005 |
| 500 | Ageron Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | May 2026 |