| 501 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 502 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 503 | Mahan Jim And Janet | Collinsville, OK 74021 | Oil & Gas Operator | Jan 2025 |
| 504 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 505 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Jan 2025 |
| 506 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |
| 507 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 508 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Jan 2025 |
| 509 | Marmik Oil Company | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2015 |
| 510 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Jan 2025 |
| 511 | Mathews & Casselman Oil Inc | Morris, OK 74445 | Oil & Gas Operator | Dec 2021 |
| 512 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Jan 2025 |
| 513 | MBR Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2025 |
| 514 | McCarty Tom | | Oil & Gas Operator | Sep 2000 |
| 515 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Feb 2025 |
| 516 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Jan 2025 |
| 517 | McIntyre M L | Oklahoma City, OK 73154-0523 | Oil & Gas Operator | Jul 1996 |
| 518 | McNic Oil & Gas Midcontinent | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | May 2024 |
| 519 | McO Resources Integrated Corp | Houston, TX 77057 | Oil Operator | Jan 1997 |
| 520 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 521 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 522 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2025 |
| 523 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 524 | Metzner, Norma J. Estate | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 1998 |
| 525 | Mewbourne Marketing Inc | Tyler, TX 75711 | Oil & Gas Operator | Mar 2013 |
| 526 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Apr 2025 |
| 527 | Mge Resources, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Jan 2025 |
| 528 | Mid Center Oil Company | | Oil & Gas Operator | Mar 2014 |
| 529 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 530 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 531 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 532 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 533 | Midnight Hour LLC | Enid, OK 73702 | Oil & Gas Operator | Apr 2020 |
| 534 | Midwestern Exploration Co. | Edmond, OK 73013 | Oil & Gas Operator | Dec 2024 |
| 535 | Mikco Inc | Tulsa, OK 74133 | Oil & Gas Operator | May 2001 |
| 536 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 537 | Minihan Production Co | Seminole, OK 74868 | Oil & Gas Operator | Jan 1997 |
| 538 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 539 | MKG Marketing Co | Oklahoma City, OK 73102 | Gas Operator | Feb 2006 |
| 540 | Mobil Exp & Prod Us Inc | Houston, TX 77060-1991 | Oil & Gas Operator | May 2001 |
| 541 | Mohawk Operating LLC | Oklahoma City, OK 73173-8907 | Gas Operator | Feb 2004 |
| 542 | Monexco | Edmond, OK 73034-3776 | Oil & Gas Operator | Mar 2008 |
| 543 | Monexco LLC | Dallas, TX 75204-2634 | Oil & Gas Operator | Jan 2025 |
| 544 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Jan 2025 |
| 545 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2025 |
| 546 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | Jan 2025 |
| 547 | Moore Robert L | Perryton, TX 79070-1275 | Oil & Gas Operator | Apr 2020 |
| 548 | Moran Oil Enterprises, LLC | Seminole, OK 74818 | Oil & Gas Operator | Dec 2024 |
| 549 | Morgan Petroleum Company | Edmond, OK 73083 | Oil & Gas Operator | Mar 1993 |
| 550 | Moss Ted A Operating Company | Oklahoma City, OK 73126-0187 | Oil & Gas Operator | Jun 1997 |
| 551 | Mountain Front Pipeline Co, Inc | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 552 | Multistates Oil Properties, NV | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 1998 |
| 553 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 554 | Nadel And Gussman, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2025 |
| 555 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 556 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 557 | Native Gas Company LLC | Edmond, OK 73083-7435 | Oil & Gas Operator | Mar 2015 |
| 558 | Natural Gas Anadarko Company | Perryton, TX 79070 | Oil & Gas Operator | Apr 2025 |
| 559 | Natural Gas Anadarko Inc | Perryton, TX 79070 | Oil & Gas Operator | May 1999 |
| 560 | Natural Gas Compression Corp | Cleveland, OK 74020 | Oil & Gas Operator | Jan 2025 |
| 561 | Natural Gas Pipeline Co Of Am LLC | Downers Grove, IL 60515-3708 | Oil & Gas Operator | Mar 2015 |
| 562 | Naylor Operating Company LLC | Perryton, TX 79079-9703 | Oil & Gas Operator | Sep 2012 |
| 563 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Apr 2025 |
| 564 | Neas Operating | Pampa, TX 79065 | Oil & Gas Operator | Oct 2011 |
| 565 | New London Oil Inc. | Houston, TX 77253 | Oil & Gas Operator | Aug 2002 |
| 566 | Nichols Water Service Inc | Forgan, OK 73938 | Oil & Gas Operator | May 2018 |
| 567 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2025 |
| 568 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Apr 2025 |
| 569 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Apr 2025 |
| 570 | Northport Production Company | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2025 |
| 571 | Northwest Disposal Corporation | Laverne, OK 73848-0504 | Oil & Gas Operator | Jul 2014 |
| 572 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Jan 2025 |
| 573 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Apr 2025 |
| 574 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 575 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2025 |
| 576 | Oakwood Resources, Inc. | Dallas, TX 75374 | Oil & Gas Operator | May 1998 |
| 577 | Occidental Energy MKT Inc | Houston, TX 77001 | Oil & Gas Operator | Jan 2011 |
| 578 | Oexco, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 579 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Apr 2025 |
| 580 | Oil Property Management, Inc. | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 581 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Jan 2025 |
| 582 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 583 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2025 |
| 584 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Jan 2025 |
| 585 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Feb 2025 |
| 586 | Olympic Petroleum Company | Tulsa, OK 74114 | Oil & Gas Operator | Jun 1998 |
| 587 | Omimex International Corporation | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Jan 2025 |
| 588 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 589 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 590 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 591 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Apr 2025 |
| 592 | Oryx Crude Trading & Transporation LP | Dallas, TX 75221 | Oil & Gas Operator | Jun 1999 |
| 593 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 594 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 595 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Apr 2025 |
| 596 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Feb 2025 |
| 597 | Oxford Oil Inc | Cleveland, OK 74020 | Oil & Gas Operator | Feb 1997 |
| 598 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 599 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 600 | P F Beeler LLC | Norman, OK 73072-7522 | Oil & Gas Operator | Feb 2025 |