| 401 | Maier Resources Inc | Oklahoma City, OK 73157-2996 | Oil & Gas Operator | Mar 2015 |
| 402 | Majoil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 1996 |
| 403 | Maloney Helen V Dba Penn-Ok Corporation | Hockessin, DE 19707-9640 | Oil & Gas Operator | Sep 2025 |
| 404 | Mapco Production Co | Billings, MT 59102 | Oil & Gas Operator | Apr 1994 |
| 405 | Maple Properties Corp | Dallas, TX 75204 | Oil & Gas Operator | Jan 1999 |
| 406 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Nov 2025 |
| 407 | Mardale Drilling Company | Oklahoma City, OK 73157 | Oil Operator | Nov 1998 |
| 408 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Nov 2025 |
| 409 | Markley Exploration | Bixby, OK 74008-5332 | Oil & Gas Operator | Jan 2014 |
| 410 | Markley L C Corporation | Fletcher, OK 73541 | Oil & Gas Operator | Aug 2002 |
| 411 | Marple Petroleum LLC | Edmond, OK 73013 | Oil Operator | Nov 2025 |
| 412 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 413 | Martin Oil Co. | Aspermont, TX 79502 | Oil & Gas Operator | Jul 2023 |
| 414 | Mason Robert A Production Co | Edmond, OK 73013-9102 | Oil & Gas Operator | May 2013 |
| 415 | Maxine Oil Company | Muskogee, OK 74401-0512 | Oil & Gas Operator | Sep 2014 |
| 416 | Maxland Oil Company | Haslet, TX 76052-5137 | Oil Operator | Nov 2014 |
| 417 | Mayes Donald W & Associates | Piedmont, OK 73078-0051 | Oil & Gas Operator | Dec 1996 |
| 418 | McGinley Jr, John R | | Gas Operator | Nov 1998 |
| 419 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 420 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Dec 2025 |
| 421 | Merrick Ward S Inc | Ardmore, OK 73402 | Oil & Gas Operator | Feb 2001 |
| 422 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 423 | Metropolitan Resources Corp | Tulsa, OK 74169-1734 | Oil & Gas Operator | Mar 2015 |
| 424 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 425 | Mid-Con Energy Operating, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | May 2020 |
| 426 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2025 |
| 427 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 428 | Milburn Robert G | Countyline, OK 73025 | Oil Operator | Apr 2020 |
| 429 | Mito Resources LLC | Edmond, OK 73013 | Oil & Gas Operator | Nov 2025 |
| 430 | Moabb Oil Corp | | Oil & Gas Operator | Apr 1998 |
| 431 | Mobil Exp & Prod Us Inc | Houston, TX 77060-1991 | Oil & Gas Operator | May 2001 |
| 432 | Moffitt W G Trust | Fort Gibson, OK 74434-4258 | Gas Operator | Nov 2019 |
| 433 | Mogo Operating, LLC | Norman, OK 73069 | Oil & Gas Operator | Nov 2025 |
| 434 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 435 | Moore & Moore Energy Inc | Purcell, OK 73080-0674 | Oil & Gas Operator | Dec 2012 |
| 436 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Nov 2025 |
| 437 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 438 | N & N Oil LLC | Duncan, OK 73533 | Oil & Gas Operator | May 2023 |
| 439 | Nabors Well Services LTD | Houston, TX 77067-4536 | Oil Operator | Apr 2011 |
| 440 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Dec 2025 |
| 441 | Nard Inc | Buffalo, OK 73834-9737 | Oil Operator | Dec 2005 |
| 442 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 443 | Natural Resources Operating LLC | Norman, OK 73071-1295 | Oil & Gas Operator | Jan 2023 |
| 444 | Navidad Operating Company, LLC | Flint, TX 75762 | Oil & Gas Operator | Jan 2025 |
| 445 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Aug 2025 |
| 446 | Newkumet Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2020 |
| 447 | Nexco Inc | Oklahoma City, OK 73102-6801 | Oil & Gas Operator | Nov 2013 |
| 448 | Nexstreem Corporation | | Oil & Gas Operator | Dec 2020 |
| 449 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 450 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Dec 2025 |
| 451 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 452 | Nooner Cynthia | Ratliff City, OK 73481 | Oil Operator | Oct 2025 |
| 453 | North American Energy Inc | Duncan, OK 73533-9604 | Oil & Gas Operator | Nov 2000 |
| 454 | Northbrook Oil & Gas Co LLC | Norman, OK 73072 | Oil & Gas Operator | Nov 2014 |
| 455 | Northbrook Oil & Gas Company | Norman, OK 73070-4916 | Oil & Gas Operator | Jun 2016 |
| 456 | Northport Production Company | Oklahoma City, OK 73113 | Oil & Gas Operator | Oct 2025 |
| 457 | Nub'S Well Servicing Inc | Ratliff City, OK 73481 | Oil & Gas Operator | Nov 2025 |
| 458 | O'Blue Corp. | Kerrville, TX 78028 | Oil & Gas Operator | Mar 1998 |
| 459 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Nov 2025 |
| 460 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Dec 2025 |
| 461 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Oct 2025 |
| 462 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 463 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2023 |
| 464 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 465 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 466 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Oct 2025 |
| 467 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Oct 2025 |
| 468 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 469 | Oklahoma Tank Service Inc | Oklahoma City, OK 73143 | Oil Operator | Aug 1997 |
| 470 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 471 | Oleum Inc | | Oil & Gas Operator | Mar 1996 |
| 472 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 473 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 474 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 475 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 476 | Over The Top LLC | Edmond, OK 73083-5371 | Gas Operator | Sep 2017 |
| 477 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Nov 2025 |
| 478 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 479 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Jul 2025 |
| 480 | Panhandle Oil & Gas Consultants Inc | Woodward, OK 73802-5011 | Oil & Gas Operator | Jul 2015 |
| 481 | Panther Operating LLC | Pauls Valley, OK 73075 | Oil & Gas Operator | Sep 2025 |
| 482 | Paramore Oil Company | Duncan, OK 73533 | Oil & Gas Operator | Apr 2022 |
| 483 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 484 | Parks Tex M Trust | Dallas, TX 75220-3864 | Oil Operator | Aug 2017 |
| 485 | Parrish Jr W F | Ardmore, OK 73401-2941 | Oil & Gas Operator | Feb 2025 |
| 486 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 487 | Patina Oklahoma Corp | Duncan, OK 73533-9523 | Oil & Gas Operator | Nov 2014 |
| 488 | Paul Burton LLC | Ardmore, OK 73401 | Oil & Gas Operator | Nov 2025 |
| 489 | Pedestal Oil Company Inc | Oklahoma City, OK 73101-1522 | Oil & Gas Operator | May 2019 |
| 490 | Pennant Energy LLC | Oklahoma City, OK 73116 | Oil Operator | Dec 2024 |
| 491 | Perkins Energy Company | Duncan, OK 73533-3853 | Oil & Gas Operator | Nov 2025 |
| 492 | Perkins Mike | Velma, OK 73091 | Oil & Gas Operator | Jan 2006 |
| 493 | Perkins, Bobby R | | Oil Operator | Mar 2017 |
| 494 | Petro Oilfield Equipment Inc | Drumright, OK 74030-1233 | Oil & Gas Operator | Dec 2010 |
| 495 | Petroleum Properties MGMT. Co. | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2014 |
| 496 | Pharoah Bob | Maysville, OK 73057 | Oil & Gas Operator | Jul 1994 |
| 497 | Phoenix Energy Partners LLC | Marlow, OK 73055 | Oil Operator | Nov 2025 |
| 498 | Phoenix Petrocorp, Inc. | McKinney, TX 75070 | Oil & Gas Operator | Nov 2025 |
| 499 | Phoenix Production Inc | Burneyville, OK 73430-2158 | Oil & Gas Operator | Feb 2025 |
| 500 | Pickelsimer Kenny | Wilson, OK 73463-6502 | Oil & Gas Operator | Aug 2014 |