| 501 | M & M Resources Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 502 | M And V Resources Inc | Crescent, OK 73028 | Oil & Gas Operator | Feb 2026 |
| 503 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Mar 2026 |
| 504 | M H Oil & Gas LLC | Okeene, OK 73763-0684 | Oil & Gas Operator | Feb 2013 |
| 505 | M M Energy Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Feb 2026 |
| 506 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Mar 2026 |
| 507 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 508 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Mar 2026 |
| 509 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 510 | Malvern Group Inc | Clearwater, FL 33758-6817 | Oil & Gas Operator | Mar 2005 |
| 511 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Mar 2026 |
| 512 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Mar 2026 |
| 513 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Mar 2026 |
| 514 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Feb 2026 |
| 515 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2026 |
| 516 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2026 |
| 517 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Mar 2026 |
| 518 | Massad George H Estate | Holdenville, OK 74848 | Oil & Gas Operator | Dec 2014 |
| 519 | Massad Oil Company | Holdenville, OK 74848-2629 | Oil Operator | Mar 2026 |
| 520 | Maverick Brothers Resources LLC | Enid, OK 73701 | Oil & Gas Operator | Feb 2026 |
| 521 | Maxim Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Feb 2026 |
| 522 | Maxwell Resources Corporation | Oklahoma City, OK 73159 | Oil & Gas Operator | Apr 2009 |
| 523 | Mayabb Oil Company Inc | Tulsa, OK 74105-5158 | Oil & Gas Operator | Oct 2025 |
| 524 | McCoy Alex W & Associates | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2009 |
| 525 | McDe Energy Company Inc | Enid, OK 73706 | Oil & Gas Operator | May 2009 |
| 526 | McKay Oil Company | Perry, OK 73077 | Oil Operator | Nov 2008 |
| 527 | McMillin C C & Company Inc | Guthrie, OK 73044 | Oil & Gas Operator | Feb 2026 |
| 528 | McO Resources Integrated Corp | Houston, TX 77057 | Oil Operator | Jan 1997 |
| 529 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 530 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Feb 2026 |
| 531 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 532 | Megaenergy Operating, Inc. | Edmond, OK 73034 | Oil & Gas Operator | Jul 2015 |
| 533 | Melzer Exploration Company | Midland, TX 79702-2083 | Oil & Gas Operator | May 2013 |
| 534 | Mermac Operating Company Inc | Norman, OK 73072 | Oil & Gas Operator | Mar 2015 |
| 535 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 536 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 537 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 538 | Midnight Hour LLC | Enid, OK 73702 | Oil & Gas Operator | Apr 2020 |
| 539 | Midstates Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2000 |
| 540 | Midwest Pipe & Supply Company | Oklahoma City, OK 73154-0245 | Oil & Gas Operator | Dec 2008 |
| 541 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 542 | Miracle Production Inc | Yukon, OK 73085-0680 | Oil & Gas Operator | Jun 2007 |
| 543 | Mito Resources LLC | Edmond, OK 73013 | Oil & Gas Operator | Mar 2026 |
| 544 | Monroe Natural Gas Inc | Norman, OK 73071 | Oil & Gas Operator | Mar 2026 |
| 545 | Moore & Moore Energy Inc | Purcell, OK 73080-0674 | Oil & Gas Operator | Dec 2012 |
| 546 | Morgan David E | Enid, OK 73702-3525 | Oil & Gas Operator | Sep 2016 |
| 547 | Mott Petroleum Corporation | Sugar Land, TX 77487 | Oil & Gas Operator | Aug 2024 |
| 548 | MSB Operating Company | Enid, OK 73703 | Oil & Gas Operator | Jan 2005 |
| 549 | MT Dora Energy LLC | Houston, OK 77056-1940 | Oil & Gas Operator | Jun 2019 |
| 550 | MT Energy LLC | Waskom, TX 75692 | Oil & Gas Operator | Jun 2026 |
| 551 | Mud Operations Inc | Ames, OK 73718-9501 | Oil & Gas Operator | Feb 2026 |
| 552 | Muegge Don E | Lamont, OK 74643-5010 | Oil & Gas Operator | Dec 1996 |
| 553 | Muras Energy Inc | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 554 | Mustang Fuel Corp. Of Oklahoma | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2016 |
| 555 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Jun 2026 |
| 556 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 557 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jun 2026 |
| 558 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 559 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 560 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Jun 2026 |
| 561 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Aug 2025 |
| 562 | Neilson Inc | Nash, OK 73761 | Oil & Gas Operator | Aug 2022 |
| 563 | Nelson Exploration Corporation | Cleveland, OK 74020-5725 | Oil & Gas Operator | Feb 2026 |
| 564 | Nemaha Environmental Services LLC | Kremlin, OK 73753 | Oil Operator | Nov 2024 |
| 565 | Nerco Oil & Gas Inc | | Oil & Gas Operator | Dec 1996 |
| 566 | Nexus Resources Corporation | Drumright, OK 74030 | Oil & Gas Operator | Jan 2013 |
| 567 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Jun 2026 |
| 568 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Jun 2026 |
| 569 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Jun 2026 |
| 570 | Northbrook Oil & Gas Company | Norman, OK 73070-4916 | Oil & Gas Operator | Jun 2016 |
| 571 | Nytex Energy LLC | Edmond, OK 73083-5946 | Oil & Gas Operator | Sep 2015 |
| 572 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 573 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Feb 2026 |
| 574 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Mar 2026 |
| 575 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Jun 2026 |
| 576 | Oberlander Leslie A Jake | Covington, OK 73730 | Oil Operator | Jun 2007 |
| 577 | Odessa Oil Investment Co., Inc. | Odessa, TX 79762 | Oil & Gas Operator | Nov 2016 |
| 578 | Ofs-Tulsa Corporation | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 579 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2026 |
| 580 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Feb 2026 |
| 581 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 582 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Feb 2026 |
| 583 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 584 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Mar 2026 |
| 585 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 586 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 587 | Olympia Oil Inc | Edmond, OK 73083-7088 | Oil & Gas Operator | Jul 2020 |
| 588 | Omimex International Corp | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Feb 2026 |
| 589 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 590 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 591 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Jun 2026 |
| 592 | Orloski John C | Bartlesville, OK 74006 | Oil & Gas Operator | Jun 2025 |
| 593 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 594 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Mar 2026 |
| 595 | Palm Oil & Gas Company | Sedona, AZ 86340 | Oil & Gas Operator | Mar 2026 |
| 596 | Pan Western Energy Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2026 |
| 597 | Panadero Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Apr 2002 |
| 598 | Panhandle Eastern Pipeline Company LP | Houston, TX 77002-6803 | Oil & Gas Operator | Oct 1999 |
| 599 | Panoak Oil & Gas Corporation | Tulsa, OK 74137 | Oil & Gas Operator | Aug 2018 |
| 600 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Jun 2026 |