| 401 | Lincoln Rock Corporation | Northfield, IL 60093 | Oil & Gas Operator | Jul 2003 |
| 402 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Aug 2024 |
| 403 | Little O Oil Company | Velma, OK 73091-0425 | Oil & Gas Operator | Apr 2015 |
| 404 | Locators Oil And Gas Inc | Guthrie, OK 73044 | Oil & Gas Operator | Oct 2022 |
| 405 | Lorentz Oil & Gas LLC | Edmond, OK 73034-7266 | Oil & Gas Operator | Nov 2024 |
| 406 | LTJ Enterprises LLC | Lone Grove, OK 73443 | Oil & Gas Operator | Aug 2024 |
| 407 | Lucky Oil Company | Comanche, OK 73529-0009 | Oil Operator | Dec 2024 |
| 408 | M M Energy, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Nov 2024 |
| 409 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2025 |
| 410 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Dec 2024 |
| 411 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 412 | Macmart Inc | Wynnewood, OK 73098 | Oil & Gas Operator | Jan 2016 |
| 413 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 414 | Maier Resources Inc | Oklahoma City, OK 73157-2996 | Oil & Gas Operator | Mar 2015 |
| 415 | Majoil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 1996 |
| 416 | Maloney Helen V Dba Penn-Ok Corporation | Hockessin, DE 19707-9640 | Oil & Gas Operator | Aug 2024 |
| 417 | Mapco Production Co | Billings, MT 59102 | Oil & Gas Operator | Apr 1994 |
| 418 | Maple Properties Corp | Dallas, TX 75204 | Oil & Gas Operator | Jan 1999 |
| 419 | Marathon Oil Company | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 420 | Mardale Drilling Company | Oklahoma City, OK 73157 | Oil Operator | Nov 1998 |
| 421 | Mark L Shidler Inc | Houston, TX 77055 | Oil & Gas Operator | Dec 2024 |
| 422 | Markley Exploration | Bixby, OK 74008-5332 | Oil & Gas Operator | Jan 2014 |
| 423 | Markley L C Corporation | Fletcher, OK 73541 | Oil & Gas Operator | Aug 2002 |
| 424 | Marple Petroleum LLC | Edmond, OK 73013 | Oil Operator | Nov 2024 |
| 425 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 426 | Martin Oil Co. | Aspermont, TX 79502 | Oil & Gas Operator | Jul 2023 |
| 427 | Mason Robert A Production Co | Edmond, OK 73013-9102 | Oil & Gas Operator | May 2013 |
| 428 | Maxine Oil Company | Muskogee, OK 74401-0512 | Oil & Gas Operator | Sep 2014 |
| 429 | Maxland Oil Company | Haslet, TX 76052-5137 | Oil Operator | Nov 2014 |
| 430 | Mayes Donald W & Associates | Piedmont, OK 73078-0051 | Oil & Gas Operator | Dec 1996 |
| 431 | McGinley Jr, John R | | Gas Operator | Nov 1998 |
| 432 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 433 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Mar 2025 |
| 434 | Merrick Ward S Inc | Ardmore, OK 73402 | Oil & Gas Operator | Feb 2001 |
| 435 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 436 | Metropolitan Resources Corp | Tulsa, OK 74169-1734 | Oil & Gas Operator | Mar 2015 |
| 437 | MGD Oil Production LLC | Healdton, OK 73438-6219 | Oil Operator | Nov 2024 |
| 438 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 439 | Mid-Con Energy Operating, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | May 2020 |
| 440 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2025 |
| 441 | Mid-Con Gas Corp | Yukon, OK 73099 | Oil & Gas Operator | Feb 2014 |
| 442 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 443 | Milburn Robert G | Countyline, OK 73025 | Oil Operator | Apr 2020 |
| 444 | Mito Resources LLC | Edmond, OK 73013 | Oil & Gas Operator | Dec 2024 |
| 445 | Moabb Oil Corp | | Oil & Gas Operator | Apr 1998 |
| 446 | Mobil Exp & Prod Us Inc | Houston, TX 77060-1991 | Oil & Gas Operator | May 2001 |
| 447 | Moffitt W G Trust | Fort Gibson, OK 74434-4258 | Gas Operator | Nov 2019 |
| 448 | Monterey Production Company LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2024 |
| 449 | Moore & Moore Energy Inc | Purcell, OK 73080-0674 | Oil & Gas Operator | Dec 2012 |
| 450 | Mullen Jr J S | | Oil & Gas Operator | Feb 1992 |
| 451 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2024 |
| 452 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 453 | N & N Oil LLC | Duncan, OK 73533 | Oil & Gas Operator | May 2023 |
| 454 | Nabors Well Services LTD | Houston, TX 77067-4536 | Oil Operator | Apr 2011 |
| 455 | Nadel And Gussman, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2025 |
| 456 | Nard Inc | Buffalo, OK 73834-9737 | Oil Operator | Dec 2005 |
| 457 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 458 | Natural Resources Operating LLC | Norman, OK 73071-1295 | Oil & Gas Operator | Jan 2023 |
| 459 | Navidad Operating Company, LLC | Flint, TX 75762 | Oil & Gas Operator | Mar 2025 |
| 460 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 461 | Newkumet Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2020 |
| 462 | Nexco Inc | Oklahoma City, OK 73102-6801 | Oil & Gas Operator | Nov 2013 |
| 463 | Nexsreem Corporation | Tyler, TX 75703 | Oil & Gas Operator | Dec 2020 |
| 464 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 465 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Mar 2025 |
| 466 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 467 | Nooner Cynthia | Ratliff City, OK 73481 | Oil Operator | Nov 2024 |
| 468 | North American Energy Inc | Duncan, OK 73533-9604 | Oil & Gas Operator | Nov 2000 |
| 469 | Northbrook Oil & Gas Co LLC | Norman, OK 73072 | Oil & Gas Operator | Nov 2014 |
| 470 | Northbrook Oil & Gas Company | Norman, OK 73070-4916 | Oil & Gas Operator | Jun 2016 |
| 471 | Northport Production Company | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2024 |
| 472 | Nub'S Well Servicing Inc | Ratliff City, OK 73481 | Oil & Gas Operator | Dec 2024 |
| 473 | O'Blue Corp. | Kerrville, TX 78028 | Oil & Gas Operator | Mar 1998 |
| 474 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Dec 2024 |
| 475 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Mar 2025 |
| 476 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Nov 2024 |
| 477 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 478 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2023 |
| 479 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 480 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2025 |
| 481 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Nov 2024 |
| 482 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Nov 2024 |
| 483 | Oklahoma Petroleum Allies LLC | Ardmore, OK 73401 | Oil Operator | Oct 2023 |
| 484 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 485 | Oklahoma Tank Service Inc | Oklahoma City, OK 73143 | Oil Operator | Aug 1997 |
| 486 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 487 | Oleum Incorporated | | Oil & Gas Operator | Mar 1996 |
| 488 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 489 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 490 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 491 | Oryx Crude Trading & Transporation LP | Dallas, TX 75221 | Oil & Gas Operator | Jun 1999 |
| 492 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 493 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Dec 2024 |
| 494 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 495 | Paloma Operating Co Inc | Houston, TX 77002-5220 | Oil & Gas Operator | Nov 2024 |
| 496 | Panhandle Oil & Gas Consultants Inc | Woodward, OK 73802-5011 | Oil & Gas Operator | Jul 2015 |
| 497 | Panther Operating LLC | Pauls Valley, OK 73075 | Oil & Gas Operator | Nov 2024 |
| 498 | Paramore Oil Company | Duncan, OK 73533 | Oil & Gas Operator | Apr 2022 |
| 499 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 500 | Parks Tex M Trust | Dallas, TX 75220-3864 | Oil Operator | Aug 2017 |