| 401 | M M Resources, Inc. | Oklahoma City, OK 73156 | Oil & Gas Operator | Sep 2018 |
| 402 | Mac Laskey Kelly Oilfield | El Dorado, KS 67042 | Oil & Gas Operator | Feb 2024 |
| 403 | Mack Oil Company | Duncan, OK 73534 | Oil & Gas Operator | Nov 2000 |
| 404 | Mackellar Inc | Oklahoma City, OK 73154-0298 | Oil & Gas Operator | Feb 2024 |
| 405 | Magaw & Zimmer | Perry, OK 73077-1055 | Oil & Gas Operator | Aug 2013 |
| 406 | Maggard Oil Co Inc | Manford, OK 74044 | Oil & Gas Operator | Sep 1997 |
| 407 | Maggard Supply & Oil Company | Mannford, OK 74044-1407 | Oil & Gas Operator | Nov 2014 |
| 408 | Magnolia Petroleum Inc | | Oil Operator | Jun 2018 |
| 409 | Maier Resources Inc | Oklahoma City, OK 73157-2996 | Oil & Gas Operator | Mar 2015 |
| 410 | Mallard Oil & Gas | Cody, WY 82414-9640 | Oil & Gas Operator | Oct 2019 |
| 411 | Malson Oil Company | Crawford, OK 73638 | Oil & Gas Operator | Dec 2016 |
| 412 | Manna Corporation | Oklahoma City, OK 73162 | Oil & Gas Operator | Dec 2014 |
| 413 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Jan 2024 |
| 414 | Mar-Bar Enterprises Inc | Cushing, OK 74023-3031 | Oil Operator | Jan 2024 |
| 415 | Marbet LLC | Edmond, OK 73013-6691 | Oil & Gas Operator | Jan 2024 |
| 416 | Marcus Exploration Inc | Piedmont, OK 73078-0308 | Oil & Gas Operator | Dec 2000 |
| 417 | Marjo Oil Company | Lockhart, TX 78644 | Oil & Gas Operator | Oct 1999 |
| 418 | Marjo Operating Company Inc | Tulsa, OK 741010729 | Oil & Gas Operator | Jan 2024 |
| 419 | Marjo Operating Mid-Continent LLC | | Oil & Gas Operator | Feb 2024 |
| 420 | Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Jan 2024 |
| 421 | Mason Robert A Production Co | Edmond, OK 73013-9102 | Oil & Gas Operator | May 2013 |
| 422 | Mathews Exploration Corporation | Oklahoma City, OK 73155-5328 | Oil & Gas Operator | Mar 2015 |
| 423 | Matthews Florine D | | Oil & Gas Operator | Jan 2020 |
| 424 | Maxim Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Jan 2024 |
| 425 | May Petroleum, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 1998 |
| 426 | McAninch J W | Tonkawa, OK 74653 | Oil & Gas Operator | Nov 2000 |
| 427 | McAninch Michael E | Tonkawa, OK 74653-4415 | Oil & Gas Operator | May 2013 |
| 428 | McAninch W Kent | Tonkawa, OK 74653-4216 | Oil & Gas Operator | Oct 2016 |
| 429 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Mar 2024 |
| 430 | McMillin C C & Company Inc | Guthrie, OK 73044-0546 | Oil & Gas Operator | Jan 2024 |
| 431 | McNeal & Shahan Oil Co Inc | | Oil & Gas Operator | Apr 2014 |
| 432 | McNeal Production Inc | Perry, OK 73077-0268 | Oil & Gas Operator | Nov 2014 |
| 433 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 434 | Meadowbrook Oil Corporation Of Ok Inc | Del City, OK 73115-3608 | Oil & Gas Operator | Feb 2024 |
| 435 | Medicine Bow Operating Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2014 |
| 436 | Mendell Petroleum Corporation | Castle Rock, CO 80104-9045 | Oil & Gas Operator | Sep 2004 |
| 437 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2024 |
| 438 | Mesa Operating LP | Irving, TX 75039-3746 | Oil & Gas Operator | Oct 2010 |
| 439 | Mid Center Oil Company | | Oil & Gas Operator | Mar 2014 |
| 440 | Mid-Con Central Expl Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2014 |
| 441 | Mid-Con Energy Operating, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2024 |
| 442 | Mid-Continent Energy Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2024 |
| 443 | Middle Bay Production Co. Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2014 |
| 444 | Midnight Hour LLC | Enid, OK 73702 | Oil & Gas Operator | Apr 2020 |
| 445 | Midstates Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2000 |
| 446 | Moabb Oil Corp | | Oil & Gas Operator | Apr 1998 |
| 447 | Montego Resources Inc | Oklahoma City, OK 73172-0192 | Oil & Gas Operator | Mar 2015 |
| 448 | Monty L Hott Production Corporation | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2024 |
| 449 | Moore Clay | Dallas, TX 75218-0217 | Oil & Gas Operator | Jan 2024 |
| 450 | Moore Richard L | Morris, OK 74445 | Oil Operator | Aug 2013 |
| 451 | Moran-K Oil LLC | Seminole, OK 74818-1295 | Oil & Gas Operator | Feb 2024 |
| 452 | Morris Pete Drilling Company | | Oil Operator | Feb 1999 |
| 453 | MT Dora Energy Corporation | Duncan, OK 73533-1829 | Oil & Gas Operator | Apr 2014 |
| 454 | MT Dora Energy LLC | Houston, OK 77056-1940 | Oil & Gas Operator | Jun 2019 |
| 455 | MT Energy LLC | Waskom, TX 75692 | Oil & Gas Operator | Apr 2024 |
| 456 | Mud Operations Inc | Ames, OK 73718-9501 | Oil & Gas Operator | Feb 2024 |
| 457 | Muegge, Clay A. | Lamont, OK 74643 | Oil & Gas Operator | Feb 2024 |
| 458 | Mullen William Company | Edmond, OK 73083-1372 | Oil & Gas Operator | May 1999 |
| 459 | Mustang Fuel Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Feb 2024 |
| 460 | Mustang Gas Products LLC | Oklahoma City, OK 73114-7406 | Oil & Gas Operator | Sep 2022 |
| 461 | Nadel And Gussman, L.L.C. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2024 |
| 462 | Naifco Oil & Gas LLC | Oklahoma City, OK 73107-0467 | Oil & Gas Operator | Jan 2024 |
| 463 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 464 | Nbi Services, Inc. | Tulsa, OK 74159 | Oil & Gas Operator | Apr 2024 |
| 465 | Nelson Exploration Corporation | | Oil & Gas Operator | Jan 2024 |
| 466 | Nemaha Environmental Services LLC | Enid, OK 73703 | Oil Operator | Feb 2024 |
| 467 | New Dominion LLC | Tulsa, OK 74119-3220 | Oil & Gas Operator | Jan 2024 |
| 468 | NFC Petroleum Corporation | Tulsa, OK 74121 | Oil & Gas Operator | Jun 1996 |
| 469 | Nielson & Associates Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 470 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2024 |
| 471 | Noble Energy Production Inc | Houston, TX 77067 | Oil & Gas Operator | Apr 2024 |
| 472 | Noble Operating Company Inc | Garden City, KS 67846 | Oil & Gas Operator | Sep 2014 |
| 473 | Nogp Operating Company LLC | | Oil & Gas Operator | Jan 2024 |
| 474 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 475 | Oil Ventures LTD | | Oil & Gas Operator | Jan 2013 |
| 476 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2024 |
| 477 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 478 | Oklahoma Liquid Resources Inc | Owasso, OK 74055-0841 | Oil & Gas Operator | Jan 2024 |
| 479 | Oklahoma Oil & Gas MGMT Inc | | Oil & Gas Operator | Jan 2024 |
| 480 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 481 | Oklahoma Petroleum Allies LLC | Ardmore, OK 73401 | Oil Operator | Oct 2023 |
| 482 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 483 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |
| 484 | Olympic Petroleum Company | Tulsa, OK 74114 | Oil & Gas Operator | Jun 1998 |
| 485 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 486 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 487 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 488 | Otc/Occ Not Assigned | | Oil & Gas Operator | Nov 2023 |
| 489 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Jan 2024 |
| 490 | Pablo Energy II, LLC | Amarillo, TX 79105 | Oil & Gas Operator | Apr 2024 |
| 491 | Pactola Development Co | Tulsa, OK 74159 | Oil & Gas Operator | Sep 2004 |
| 492 | Pal Kids Inc | Coronado, CA 92118 | Oil & Gas Operator | Nov 2000 |
| 493 | Palm Oil & Gas Company | Sedona, AZ 86340-4808 | Oil & Gas Operator | Feb 2024 |
| 494 | Pan Western Energy Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Apr 2024 |
| 495 | Panenergy Services Inc | Houston, TX 77525 | Oil & Gas Operator | May 2001 |
| 496 | Paradigm Twenty LLC | | Oil & Gas Operator | Jan 2024 |
| 497 | Paramount Petroleum Corp | Dallas, TX 75374 | Oil Operator | Dec 2000 |
| 498 | Parker & Parsley Dev Co | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 499 | Parkway Petroleum, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Jul 1997 |
| 500 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |