| 401 | Little River Energy Company | Drumright, OK 74030 | Oil & Gas Operator | Sep 2025 |
| 402 | Little Thunder, LLC | Bartlesville, OK 74003 | Oil Operator | Aug 2025 |
| 403 | Lo-Jel Energy LLC | Oklahoma City, OK 73162-7418 | Oil & Gas Operator | Nov 2019 |
| 404 | Locklin Exp & Prod Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2011 |
| 405 | Loki Oil LLC | Cushing, OK 74023 | Oil & Gas Operator | Nov 2024 |
| 406 | Lord Enterprises Inc | Oklahoma City, OK 73106-5050 | Oil & Gas Operator | Sep 2000 |
| 407 | Lovell Keith | Stillwater, OK 74074-6459 | Oil & Gas Operator | Jan 2020 |
| 408 | Lu-Ray Petroleum LLC | Oklahoma City, OK 73121-1607 | Oil & Gas Operator | Sep 2025 |
| 409 | Lucky Ace Petroleum LLC | Carrollton, TX 75010-4232 | Oil Operator | Oct 2021 |
| 410 | Luther Oil Inc | Cameron Park, CA 95682-8865 | Oil & Gas Operator | Apr 2020 |
| 411 | LVM Oil Production LLC | Yale, OK 74085-6688 | Oil & Gas Operator | Jul 2021 |
| 412 | M & M Petroleum Company | Mannford, OK 74044-0462 | Oil Operator | Apr 2020 |
| 413 | M & M Resources Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 414 | M E Klein & Associates LLC | Washington, OK 73093-4663 | Oil & Gas Operator | Sep 2025 |
| 415 | M. S. Productions, Inc. | Pittsburg, KS 66762 | Oil & Gas Operator | Nov 2019 |
| 416 | Mac Engineering & Operating Co | | Oil & Gas Operator | May 2005 |
| 417 | Mack Energy Co. | Duncan, OK 73534 | Oil & Gas Operator | Sep 2025 |
| 418 | Mackellar Inc | Oklahoma City, OK 73116-7101 | Oil & Gas Operator | Sep 2025 |
| 419 | Maggard Oil Co Inc | Manford, OK 74044 | Oil & Gas Operator | Sep 1997 |
| 420 | Maggard Supply & Oil Company | Mannford, OK 74044-1407 | Oil & Gas Operator | Nov 2014 |
| 421 | Magnum Energy Inc | Norman, OK 73072-2403 | Oil & Gas Operator | Aug 2025 |
| 422 | Major Oil Co LLC | Drumright, OK 74030 | Oil & Gas Operator | May 2025 |
| 423 | Majors Jimmy R | Osceola, NE 68651-0726 | Oil & Gas Operator | Sep 2000 |
| 424 | Mallorn Energy LLC | Edmond, OK 73034 | Oil & Gas Operator | Aug 2025 |
| 425 | Manna Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Dec 2014 |
| 426 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Sep 2025 |
| 427 | Marathon Oil Company LLC | Houston, TX 77079 | Oil & Gas Operator | Sep 2025 |
| 428 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Sep 2025 |
| 429 | Marjo Oil Company | Lockhart, TX 78644 | Oil & Gas Operator | Oct 1999 |
| 430 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Aug 2025 |
| 431 | Marjo Operating Mid-Continent LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2025 |
| 432 | Mark Petroleum Inc | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2018 |
| 433 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Aug 2025 |
| 434 | Marsh Oil & Gas Company | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2025 |
| 435 | Martin John R | Cushing, OK 74023 | Oil & Gas Operator | Apr 1995 |
| 436 | Martin Tank Truck & Casing Pulling Inc | Cushing, OK 74023 | Oil & Gas Operator | Apr 2015 |
| 437 | Martin'S Resources LLC | Woodward, OK 73801-5641 | Oil & Gas Operator | Aug 2025 |
| 438 | Masham Production Corporation | Enid, OK 73702 | Oil & Gas Operator | Aug 2000 |
| 439 | Mathews Exploration Corporation | Oklahoma City, OK 73155-5328 | Oil & Gas Operator | Mar 2015 |
| 440 | Mattea Oil & Gas LLC | Drumright, OK 74023 | Oil & Gas Operator | Jun 2025 |
| 441 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Dec 2025 |
| 442 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Oct 2025 |
| 443 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Aug 2025 |
| 444 | McMillin C C & Company Inc | Guthrie, OK 73044 | Oil & Gas Operator | Aug 2025 |
| 445 | Meade Energy Corporation | Oklahoma City, OK 73118-4015 | Oil & Gas Operator | Sep 2025 |
| 446 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Sep 2025 |
| 447 | Mel-Ray Oil Company | Nowata, OK 74048-0149 | Oil & Gas Operator | Mar 2004 |
| 448 | Mendell Petroleum Corporation | Castle Rock, CO 80104-9045 | Oil & Gas Operator | Sep 2004 |
| 449 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 450 | Metro Energy LTD | Scottsdale, AZ 85254 | Oil Operator | Aug 2000 |
| 451 | Metzner, Norma J. Estate | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 1998 |
| 452 | Mickalson Operating Company | Cleveland, OK 74020 | Oil & Gas Operator | Sep 2025 |
| 453 | Mid-Con Energy Operating, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | May 2020 |
| 454 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 455 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2025 |
| 456 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 457 | Midgard Energy Company | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 458 | Midwest Energy Corporation | Tulsa, OK 74105-6083 | Oil & Gas Operator | Aug 2016 |
| 459 | Mikal R Brown Oil LLC | Cleveland, OK 74020-6475 | Oil Operator | Dec 2022 |
| 460 | Miller B Investments | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2007 |
| 461 | Miller Exploration Company | Tulsa, OK 74136-1020 | Oil & Gas Operator | Mar 2015 |
| 462 | Miller-McGee Operating Inc | Stroud, OK 74079 | Oil & Gas Operator | Sep 2025 |
| 463 | Milmac Operating Company | Lubbock, TX 79408-2976 | Oil & Gas Operator | Sep 2004 |
| 464 | Miner Rick Oil Inc | Drumright, OK 74030-0373 | Oil & Gas Operator | Apr 2022 |
| 465 | Minuja Oil And Gas LLC | Corpus Christi, TX 78401 | Oil & Gas Operator | Sep 1996 |
| 466 | MJM Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 467 | Monarch Petroleum Corporation | FT Worth, TX 76102 | Oil & Gas Operator | Dec 2019 |
| 468 | Montgomery Exploration Co LTD | Dallas, TX 75204-2634 | Oil & Gas Operator | Sep 2025 |
| 469 | Moore Clay | Bradenton, FL 34211 | Oil & Gas Operator | Aug 2025 |
| 470 | Moran Oil Enterprises LLC | Seminole, OK 74818 | Oil & Gas Operator | Dec 2019 |
| 471 | Morgan David E | Enid, OK 73702-3525 | Oil & Gas Operator | Sep 2016 |
| 472 | Morris Roger Dan | Cushing, OK 74023 | Oil & Gas Operator | Jun 2025 |
| 473 | Morrison International Energy Inc | Oklahoma City, OK 73189-0537 | Oil & Gas Operator | Feb 2025 |
| 474 | MT Dora Energy Corporation | Duncan, OK 73533-1829 | Oil & Gas Operator | Apr 2014 |
| 475 | MT Dora Energy LLC | Houston, OK 77056-1940 | Oil & Gas Operator | Jun 2019 |
| 476 | Mueggenborg Derrick R Dba DRM Oil & Gas | Yale, OK 74085 | Oil Operator | Sep 2025 |
| 477 | Naifco Oil & Gas LLC | Oklahoma City, OK 73107 | Oil & Gas Operator | Sep 2025 |
| 478 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 479 | Natomas North America Inc | | Oil & Gas Operator | Aug 1993 |
| 480 | Natural Progression Oil & Gas Corp | Stillwater, OK 74075 | Oil & Gas Operator | Sep 2025 |
| 481 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Dec 2025 |
| 482 | Nerco Oil & Gas Inc | | Oil & Gas Operator | Dec 1996 |
| 483 | New Century Petroleum Corp | Oklahoma City, OK 73105 | Oil & Gas Operator | May 2013 |
| 484 | New Dominion LLC | Tulsa, OK 74119-3220 | Oil & Gas Operator | Sep 2025 |
| 485 | New Energy Corporation | Rancho Santa Fe, CA 92067-1990 | Oil & Gas Operator | Jul 2024 |
| 486 | Nexus Resources Corporation | Drumright, OK 74030 | Oil & Gas Operator | Jan 2013 |
| 487 | NHH Inc | Oklahoma City, OK 73162-7418 | Oil & Gas Operator | Feb 2002 |
| 488 | Nivens Productions LLC | Coyle, OK 73027-9785 | Oil & Gas Operator | Aug 2024 |
| 489 | NM&O Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 490 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 491 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Dec 2025 |
| 492 | Nogp Operating Company Inc | Tomball, TX 77377 | Oil & Gas Operator | Sep 2025 |
| 493 | Nondorf Oil & Gas Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2008 |
| 494 | Oak Hill Petroleum Corporation | Oklahoma City, OK 73116-5627 | Oil & Gas Operator | Jul 2025 |
| 495 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 496 | Ochiltree Oil Company | Edmond, OK 73034 | Oil & Gas Operator | Apr 2020 |
| 497 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 498 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 499 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 500 | Oil State Petroleum Inc | Jennings, OK 74038 | Oil & Gas Operator | Sep 2025 |