| 401 | Leasehold Management Corp | Oklahoma City, OK 73107 | Oil & Gas Operator | Nov 2024 |
| 402 | Leavell Resources Corporation | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 403 | Legacy - M & K Corporation | Dallas, TX 75231-0969 | Oil & Gas Operator | Jan 2025 |
| 404 | Lewis Oil Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Jan 2026 |
| 405 | Lewis, R. J. Oil Company | Stillwater, OK 74076 | Oil & Gas Operator | Apr 2014 |
| 406 | Lindenmuth & Associates Inc | Austin, TX 78703 | Oil & Gas Operator | Jun 2025 |
| 407 | Little River Energy Company | Drumright, OK 74030 | Oil & Gas Operator | Feb 2026 |
| 408 | Little Thunder, LLC | Bartlesville, OK 74003 | Oil Operator | Jan 2026 |
| 409 | Lobar Oil Co LLC | Edmond, OK 73013 | Oil & Gas Operator | Jan 2026 |
| 410 | Lord Enterprises Inc | Oklahoma City, OK 73106-5050 | Oil & Gas Operator | Sep 2000 |
| 411 | Lre Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2016 |
| 412 | Lu-Ray Petroleum LLC | Oklahoma City, OK 73121-1607 | Oil & Gas Operator | Feb 2026 |
| 413 | Lunar Investments Inc | Oklahoma City, OK 73118-4823 | Oil & Gas Operator | Jan 2026 |
| 414 | Luther Oil Inc | Cameron Park, CA 95682-8865 | Oil & Gas Operator | Apr 2020 |
| 415 | Luween Energy LLC | Oklahoma City, OK 73128 | Oil & Gas Operator | Dec 2025 |
| 416 | M & M Resources Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 417 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Feb 2026 |
| 418 | M G Energy LLC | Cushing, OK 74023 | Oil & Gas Operator | Jan 2026 |
| 419 | Mac Engineering & Operating Co | | Oil & Gas Operator | May 2005 |
| 420 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Feb 2026 |
| 421 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Feb 2026 |
| 422 | Magaw & Zimmer | Perry, OK 73077-1055 | Oil & Gas Operator | Aug 2013 |
| 423 | Maggard Oil Co Inc | Manford, OK 74044 | Oil & Gas Operator | Sep 1997 |
| 424 | Maggard Supply & Oil Company | Mannford, OK 74044-1407 | Oil & Gas Operator | Nov 2014 |
| 425 | Magma Resources LLC | Paoli, OK 73074 | Oil & Gas Operator | Apr 2025 |
| 426 | Magnum Energy Inc | Norman, OK 73072-2403 | Oil & Gas Operator | Feb 2026 |
| 427 | Maguire James Q Inc | Norman, OK 73070-1748 | Oil & Gas Operator | Jun 2011 |
| 428 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 429 | Manna Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Dec 2014 |
| 430 | Mantex Inc | Tulsa, OK 74114-6234 | Oil & Gas Operator | Mar 2015 |
| 431 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Feb 2026 |
| 432 | Maple Properties Corp | Dallas, TX 75204 | Oil & Gas Operator | Jan 1999 |
| 433 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Feb 2026 |
| 434 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Jan 2026 |
| 435 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Jan 2026 |
| 436 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2026 |
| 437 | Marshall Oil Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2017 |
| 438 | Martin John R | Cushing, OK 74023 | Oil & Gas Operator | Apr 1995 |
| 439 | Martin Tank Truck & Casing Pulling Inc | Cushing, OK 74023 | Oil & Gas Operator | Apr 2015 |
| 440 | Masham Production Corporation | Enid, OK 73702 | Oil & Gas Operator | Aug 2000 |
| 441 | Mason Robert A | | Oil Operator | May 1993 |
| 442 | Mason Robert A Production Co | Edmond, OK 73013-9102 | Oil & Gas Operator | May 2013 |
| 443 | Mattea Oil & Gas LLC | Drumright, OK 74023 | Oil & Gas Operator | Jun 2025 |
| 444 | May Energy Company | Stroud, OK 74079 | Oil & Gas Operator | May 2013 |
| 445 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Apr 2026 |
| 446 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | Jan 2026 |
| 447 | McCord Al Inc | Norman, OK 73072-6720 | Oil & Gas Operator | Feb 2011 |
| 448 | McFerran Operating LLC | Seminole, OK 74868-6202 | Oil & Gas Operator | Jan 2026 |
| 449 | McGriff Craig Exploration Inc | Oklahoma City, OK 73172-0364 | Oil & Gas Operator | Mar 2023 |
| 450 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 451 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Feb 2026 |
| 452 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Feb 2026 |
| 453 | Mega Resources Inc | Dallas, TX 75225-0186 | Oil & Gas Operator | Jan 2001 |
| 454 | Mel-Ray Oil Company | Nowata, OK 74048-0149 | Oil & Gas Operator | Mar 2004 |
| 455 | Mesa Exploration Company Inc | Shawnee, OK 74801 | Oil & Gas Operator | Feb 2026 |
| 456 | Michael Goodnight Operating LLC | St Louis, OK 74866 | Oil & Gas Operator | Feb 2026 |
| 457 | Mickalson Operating Company | Cleveland, OK 74020 | Oil & Gas Operator | Feb 2026 |
| 458 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 459 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2026 |
| 460 | Mid-Way Environmental Services Inc | Stroud, OK 74079 | Oil Operator | Apr 2025 |
| 461 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 462 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 463 | Miller John Production | Bristow, OK 74010-2455 | Oil & Gas Operator | Jul 2016 |
| 464 | Miller-McGee Operating Inc | Stroud, OK 74079 | Oil & Gas Operator | Jan 2026 |
| 465 | Milmac Operating Company | Lubbock, TX 79408-2976 | Oil & Gas Operator | Sep 2004 |
| 466 | Miner Rick Oil Inc | Drumright, OK 74030-0373 | Oil & Gas Operator | Apr 2022 |
| 467 | Minihan Oil And Gas Company | Seminole, OK 74868-9790 | Oil & Gas Operator | Sep 2014 |
| 468 | Mission Leasing LTD | Tulsa, OK 74136 | Oil Operator | Dec 2000 |
| 469 | Montclair Energy LLC | Edmond, OK 73034-7291 | Oil & Gas Operator | Jan 2026 |
| 470 | Moran Oil Enterprises LLC | Seminole, OK 74818 | Oil & Gas Operator | Dec 2019 |
| 471 | Moran-K Oil LLC | Seminole, OK 74868 | Oil & Gas Operator | Feb 2026 |
| 472 | Morgan Energy Corporation | Englewood, CO 80110 | Oil & Gas Operator | Mar 2006 |
| 473 | Morrison International Energy Inc | Oklahoma City, OK 73189-0537 | Oil & Gas Operator | Feb 2025 |
| 474 | Morton Drilling Company | Bristow, OK 74010-1279 | Oil & Gas Operator | Jun 1995 |
| 475 | Morton Production Inc | Ada, OK 74820-2643 | Oil & Gas Operator | Sep 2014 |
| 476 | Moss Ted A Operating Company | Oklahoma City, OK 73126-0187 | Oil & Gas Operator | Jun 1997 |
| 477 | MT Energy LLC | Waskom, TX 75692 | Oil & Gas Operator | Apr 2026 |
| 478 | Musgrove Casey Oil | Ponca City, OK 74602-0391 | Oil & Gas Operator | Jun 2017 |
| 479 | Myjo Oil Corporation | Breckenridge, TX 76024 | Oil Operator | Jul 1996 |
| 480 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2026 |
| 481 | Naifco Oil & Gas LLC | Oklahoma City, OK 73107 | Oil & Gas Operator | Jan 2026 |
| 482 | National Cooperative RFG Assoc | McPherson, KS 67460-1404 | Oil & Gas Operator | Oct 2025 |
| 483 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 484 | Natural Progression Oil & Gas Corp | Stillwater, OK 74075 | Oil & Gas Operator | Jan 2026 |
| 485 | Natural Resources Operating LLC | Norman, OK 73071-1295 | Oil & Gas Operator | Jan 2023 |
| 486 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Apr 2026 |
| 487 | Nelson Exploration Corporation | Cleveland, OK 74020-5725 | Oil & Gas Operator | Feb 2026 |
| 488 | Nerco Oil & Gas Inc | | Oil & Gas Operator | Dec 1996 |
| 489 | New Century Petroleum Corp | Oklahoma City, OK 73105 | Oil & Gas Operator | May 2013 |
| 490 | New Dominion LLC | Tulsa, OK 74119-3220 | Oil & Gas Operator | Feb 2026 |
| 491 | Newell Oil And Gas LLC | Shawnee, OK 74801-5783 | Oil & Gas Operator | Feb 2026 |
| 492 | Nexus Resources Corporation | Drumright, OK 74030 | Oil & Gas Operator | Jan 2013 |
| 493 | Nielson & Associates, Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 494 | NM&O Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 495 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2026 |
| 496 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Apr 2026 |
| 497 | Noble Operating Company Inc | Garden City, KS 67846 | Oil & Gas Operator | Sep 2014 |
| 498 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 499 | Norman Production Company | Chandler, OK 74834-8538 | Oil & Gas Operator | May 2015 |
| 500 | North Star Exploration Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2026 |