| 501 | Allegheny Natural Resources Inc | Gibsonia, PA 15044-8055 | Gas Operator | Dec 2019 |
| 502 | Allegheny Producers Inc | Cambridge, OH 43725 | Oil & Gas Operator | Dec 1984 |
| 503 | Allegiance Operating Inc. | Wichita Falls, TX 76307 | Oil Operator | Aug 2026 |
| 504 | Allegiant Resources, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Aug 2026 |
| 505 | Allegro Investments, Inc. | Victoria, TX 77903 | Oil & Gas Operator | Nov 2020 |
| 506 | Allegro Operating, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Aug 2026 |
| 507 | Allen & Allen Oil Co | | Oil Operator | Apr 2026 |
| 508 | Allen & Grace Oil Company | Kingsbury, TX 78638 | Oil & Gas Operator | Jul 1997 |
| 509 | Allen & Shumate, Inc. | Alice, TX 78333 | Oil & Gas Operator | Jan 1996 |
| 510 | Allen Benne | Ramona, OK 74061-3612 | Oil Operator | Aug 2010 |
| 511 | Allen Brothers | | Oil & Gas Operator | Dec 2024 |
| 512 | Allen Brothers Company | Oil City, LA 71061 | Oil & Gas Operator | Apr 1997 |
| 513 | Allen Delmar | Okemah, OK 74859-9801 | Oil & Gas Operator | Dec 2000 |
| 514 | Allen Drilling C | | Oil & Gas Operator | Nov 1994 |
| 515 | Allen Drilling Company | Great Bend, KS 67530 | Oil & Gas Operator | Dec 2009 |
| 516 | Allen Energy LLC | Cochranton, PA 16314-6214 | Oil & Gas Operator | Dec 2025 |
| 517 | Allen J D & Comp | | Oil Operator | Jan 1983 |
| 518 | Allen J W Revocable Trust | Tulsa, OK 74101-0411 | Oil Operator | Nov 1998 |
| 519 | Allen K Trobaugh | Midland, TX 79705 | Oil & Gas Operator | Mar 1997 |
| 520 | Allen Kent | Okemah, OK 74859-9700 | Oil Operator | Aug 2025 |
| 521 | Allen Mabel C | Dublin, OH 43017 | Oil Operator | Dec 1988 |
| 522 | Allen Michael | Broken Arrow, OK 74014-2239 | Oil & Gas Operator | Mar 2026 |
| 523 | Allen Oil & Gas LLC | Ardmore, OK 73401 | Oil Operator | Aug 2022 |
| 524 | Allen Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Jun 2016 |
| 525 | Allen Operating Company, LLC | | Oil & Gas Operator | Dec 2022 |
| 526 | Allen Petroleum Company | | Oil Operator | Apr 1996 |
| 527 | Allen Petroleum, Inc. | | Oil Operator | Jul 2010 |
| 528 | Allen Richard R | Bartlesville, OK 74005 | Oil Operator | Aug 1999 |
| 529 | Allen Wade | Okmulgee, OK 74447-9717 | Oil & Gas Operator | Apr 2026 |
| 530 | Allen, C. L. (Doie) | Wichita Falls, TX 76309 | Oil & Gas Operator | Aug 2026 |
| 531 | Allen, Mabel F. | Corpus Christ, TX 78412 | Oil & Gas Operator | Jul 2002 |
| 532 | Allenco Energy Inc. | | Oil & Gas Operator | Dec 2025 |
| 533 | Allenergy Operating Co Inc | Coffeyville, KS 67337-6653 | Oil & Gas Operator | Mar 2015 |
| 534 | Allenergy, Inc. | Grove, OK 74345 | Oil & Gas Operator | Jul 2012 |
| 535 | Alliance Exploration Co., LLC | Tulsa, OK 74119 | Oil Operator | Apr 2017 |
| 536 | Alliance Exploration Corp. | | Oil & Gas Operator | Mar 1983 |
| 537 | Alliance Oil & Gas Co Inc | Corinth, TX 76205 | Oil & Gas Operator | Mar 2015 |
| 538 | Alliance Operating Corporation | | Oil & Gas Operator | Jan 1995 |
| 539 | Alliance Petroleum Co., LLC | | Oil & Gas Operator | Dec 2021 |
| 540 | Alliance Petroleum Corporation | Canton, OH 44718-2553 | Oil & Gas Operator | Dec 2019 |
| 541 | Alliance Resources (USA), Inc. | | Oil & Gas Operator | Oct 2002 |
| 542 | Alliance Resources Corporation | Dallas, TX 75367 | Oil & Gas Operator | Nov 2024 |
| 543 | Alliance Resources LLC | Midland, TX 79705 | Oil & Gas Operator | Aug 2026 |
| 544 | Allied Energy Corporation | | Oil & Gas Operator | Dec 2025 |
| 545 | Allied Energy Operating, LLC | McKinney, TX 75071 | Oil Operator | Aug 2026 |
| 546 | Allied Energy, Inc. | Saratoga, CA 95070 | Oil & Gas Operator | Dec 2021 |
| 547 | Allied Exploration, Inc. | | Oil & Gas Operator | May 2021 |
| 548 | Allied Oil Compa | | Oil & Gas Operator | Feb 1995 |
| 549 | Allied Oil Company, Inc. | Taneyville, MO 65759 | Oil Operator | Apr 1996 |
| 550 | Allied Oil Field Services LTD | Willoughby, OH 44094 | Oil & Gas Operator | Dec 2021 |
| 551 | Allied Operating LLC | Bowling Green, KY 42101-3980 | Oil & Gas Operator | Sep 2015 |
| 552 | Allied Operating Texas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2026 |
| 553 | Allied Petroleum Company | | Gas Operator | Dec 1992 |
| 554 | Allied Petroleum Inc | Oklahoma City, OK 73116-1516 | Oil & Gas Operator | Jun 2014 |
| 555 | Allied Western Petroleum | | Oil & Gas Operator | Dec 2025 |
| 556 | Allied-Gulf Energy, LLC | Lafayette, LA 70508 | Oil & Gas Operator | Aug 2026 |
| 557 | Alligator Rock Well Service LLC | Velma, OK 73491-0627 | Oil & Gas Operator | May 2026 |
| 558 | Allison Bros DRLG Co Inc | | Oil & Gas Operator | Dec 2015 |
| 559 | Allison Dean Oil | | Oil & Gas Operator | Nov 1994 |
| 560 | Allison J A | | Oil & Gas Operator | Nov 1995 |
| 561 | Allison Lease Services LLC | Graham, TX 76450 | Oil & Gas Operator | Aug 2026 |
| 562 | Allison Oil Comp | | Oil Operator | Dec 1986 |
| 563 | Allison Operating Co., L.C. | Wichita, KS 67202 | Oil & Gas Operator | Dec 1998 |
| 564 | Allison Tom & Shelly Dba T & S Oil Company | Bartlesville, OK 74006-0722 | Oil & Gas Operator | Nov 2025 |
| 565 | Allison/Hobbs Inc. | Alba, TX 75410 | Oil & Gas Operator | Aug 2026 |
| 566 | Allshouse Terrence L Jr | Grand Valley, PA 16420-1930 | Oil & Gas Operator | Dec 2025 |
| 567 | Allsop Oil And Gas Company, Inc. | Farmers BRNCH, TX 75234 | Oil & Gas Operator | Nov 1996 |
| 568 | Allstar Oil And Gas Inc. | | Oil & Gas Operator | Nov 1992 |
| 569 | Allstate Energy Corp | Smithville, WV 26178 | Oil & Gas Operator | Dec 2021 |
| 570 | Alltex Exploration, Inc. | Houston, TX 77056 | Oil & Gas Operator | Aug 2026 |
| 571 | Allwaste Oilfield Services Inc | | Oil Operator | May 1996 |
| 572 | Alma Gas Co Inc | Alma, NY 14708 | Oil & Gas Operator | Dec 2025 |
| 573 | Almac Engineering | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2007 |
| 574 | Almack John And Glenda | Perry, OK 73077-8819 | Oil & Gas Operator | Apr 2016 |
| 575 | Alme, Henry A. | Cut Bank, MT 59427 | Gas Operator | Mar 2026 |
| 576 | Almond Crest Oil LLC | | Oil & Gas Operator | Dec 2025 |
| 577 | Almont Energy LLC | Kingfisher, OK 73750-0901 | Oil & Gas Operator | Oct 2021 |
| 578 | Aln Resources Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 1993 |
| 579 | Alna Energy LLC | New Lexington, OH 43764 | Oil & Gas Operator | Dec 2024 |
| 580 | Alog, LLC | Brewton, AL 36427 | Oil & Gas Operator | Dec 2025 |
| 581 | Alpar Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jul 2011 |
| 582 | Alpha Energy | Anson, TX 79501 | Oil & Gas Operator | Oct 2016 |
| 583 | Alpha Energy Texas Operating LLC | Denver, CO 80222 | Oil & Gas Operator | Apr 2026 |
| 584 | Alpha Energy, LLC | Ashland, OR 97520 | Oil Operator | Dec 2009 |
| 585 | Alpha Exploration Co. | Wichita Falls, TX 76309 | Oil & Gas Operator | Oct 1998 |
| 586 | Alpha Gamma Onshore, LLC | Midland, TX 79702 | Oil Operator | Aug 2026 |
| 587 | Alpha Gas Corporation | Jane Lew, WV 26378 | Oil & Gas Operator | Dec 2007 |
| 588 | Alpha Management | | Oil & Gas Operator | Jan 1994 |
| 589 | Alpha Oil & Gas Inc. | | Oil & Gas Operator | Sep 1989 |
| 590 | Alpha Oil Company | | Oil Operator | Jul 2004 |
| 591 | Alpha Omega Petroleum, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Mar 1996 |
| 592 | Alpha Petro Development Inc | Tulsa, OK 74136-7048 | Oil & Gas Operator | May 2013 |
| 593 | Alpha Petroleum | | Oil & Gas Operator | Jan 2025 |
| 594 | Alpha Shale Res LP | Canonsburg, PA 15317-9554 | Gas Operator | Aug 2017 |
| 595 | Alpine Drilling | | Oil & Gas Operator | May 1994 |
| 596 | Alpine Drilling Company, Inc. | Wichita, KS 67202 | Oil & Gas Operator | Apr 2000 |
| 597 | Alpine Energy Corp. | | Oil & Gas Operator | Jun 2004 |
| 598 | Alpine Energy, Inc. | | Oil & Gas Operator | Dec 1999 |
| 599 | Alpine Expl. Companies, Inc. | | Oil & Gas Operator | Jan 2024 |
| 600 | Alpine Exploration Co, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Nov 2017 |