| 401 | Magruder '81, LTD. | Midland, TX 79701 | Oil & Gas Operator | Jan 1995 |
| 402 | Magruder, Edwin H., Jr. | Midland, TX 79701 | Oil & Gas Operator | Oct 2019 |
| 403 | Mammoth Exploration LLC | Midland, TX 79701 | Oil & Gas Operator | Jul 2023 |
| 404 | Manhattan Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 405 | Manning, Jack | Odessa, TX 79760 | Oil & Gas Operator | Dec 2003 |
| 406 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 407 | Maralo, LLC | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 408 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Aug 2025 |
| 409 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 410 | Marshall & Winston, Inc. | Midland, TX 79710 | Oil & Gas Operator | Aug 2025 |
| 411 | Martin Foree Operating II, LLC | Royse City, TX 75189 | Oil & Gas Operator | Oct 2025 |
| 412 | Martin Foree Operating, LLC | Royse City, TX 75189 | Oil & Gas Operator | Oct 2025 |
| 413 | Martin Oil LLC | Madison, KS 66860 | Oil Operator | Jun 2025 |
| 414 | Martin, Jimmy Inc | San Angelo, TX 76904 | Oil & Gas Operator | Oct 2025 |
| 415 | Mas Operating Co. | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 416 | Maverick Permian LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 417 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 418 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 419 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | Oct 2025 |
| 420 | McClure Oil Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 421 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Jul 2025 |
| 422 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 423 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Oct 2025 |
| 424 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 425 | McDonnold Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 426 | McMoran Oil & Gas LLC | New Orleans, LA 70160 | Oil & Gas Operator | Oct 2021 |
| 427 | Memorial Production Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 428 | Meridian Oil Inc. | Houston, TX 77210 | Oil & Gas Operator | Aug 1996 |
| 429 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 430 | Merrico Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2008 |
| 431 | Mesquite SWD Inc | Carlsbad, NM 88221 | Oil & Gas Operator | Oct 2025 |
| 432 | Mewbourne Oil Company | Tyler, TX 75711 | Oil & Gas Operator | Oct 2025 |
| 433 | Mexco Energy Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2020 |
| 434 | Mid-States Operating Company | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 435 | Midenergy Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 436 | Mills, Pete | Midland, TX 79707 | Oil & Gas Operator | Sep 2005 |
| 437 | Miltex Oil Company | Boerne, TX 78006 | Oil & Gas Operator | Oct 2025 |
| 438 | Minihan Oil & Gas Corporation | Midland, TX 79704 | Oil & Gas Operator | Apr 2004 |
| 439 | Minihan Oil & Gas LTD. | Denver, CO 80202 | Oil & Gas Operator | Jul 2006 |
| 440 | Miranda Energy Corporation | Midland, TX 79705 | Oil & Gas Operator | Jun 2016 |
| 441 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 442 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 443 | Momentum Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 444 | Momentum Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2004 |
| 445 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2025 |
| 446 | Moss SWD, LLC | Andrews, TX 79714 | Oil Operator | Oct 2025 |
| 447 | Mr Oil Company | Monahans, TX 79756 | Oil & Gas Operator | Nov 2004 |
| 448 | Mulloy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 449 | Munn, W. H. Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2002 |
| 450 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 451 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |
| 452 | National Energy Group, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 453 | Naumann Oil & Gas, Inc. | Austin, TX 78716 | Oil & Gas Operator | Oct 2025 |
| 454 | NBL Permian LLC | Houston, TX 77070 | Oil & Gas Operator | Aug 2018 |
| 455 | Neg Operating LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Jun 2025 |
| 456 | Newfield Expl. Mid-Con. Inc | Tulsa, OK 74172 | Oil & Gas Operator | Jan 2015 |
| 457 | Newman Cubed, Inc. | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2025 |
| 458 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | Oct 2025 |
| 459 | Nicki T Oil & Gas LLC | Midland, TX 79711 | Oil Operator | Oct 2025 |
| 460 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 461 | North Lake Resources LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Oct 2025 |
| 462 | North Operating Company | Canton, TX 75103 | Oil & Gas Operator | Oct 2025 |
| 463 | Northstar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 464 | Now Development Co., Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2017 |
| 465 | O & O Operators, LLC. | Fate, TX 75132 | Oil & Gas Operator | Oct 2025 |
| 466 | O'Brien, George H. Jr. | Midland, TX 79701 | Oil & Gas Operator | Jun 1994 |
| 467 | O'Ryan Oil And Gas | Odessa, TX 79768 | Oil & Gas Operator | Oct 2025 |
| 468 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 469 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 470 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 471 | Ocotillo Energy Resources, LLC | Odessa, TX 79765 | Oil Operator | Oct 2025 |
| 472 | Octane Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 473 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 474 | Oil & Gas Properties | Midland, TX 79704 | Oil & Gas Operator | Oct 2025 |
| 475 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 476 | Ok Arena Operating Company | Oklahoma City, OK 73101 | Oil & Gas Operator | Oct 2025 |
| 477 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 478 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Oct 2025 |
| 479 | Omar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 480 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 481 | Orion Energen Inc. | Austin, TX 78731 | Oil & Gas Operator | Jul 2023 |
| 482 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 483 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2025 |
| 484 | Overflow Energy, LLC | Perryton, TX 79070 | Oil & Gas Operator | Oct 2025 |
| 485 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 486 | Owl Ops LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 487 | Oxbow Petroleum, LLC | Midland, TX 79703 | Oil & Gas Operator | May 2025 |
| 488 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 489 | Oxy USA WTP LP | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 490 | P-R-O Management, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 491 | P.O.&G. Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 492 | Pactola Development Co | Tulsa, OK 74159 | Oil & Gas Operator | Sep 2004 |
| 493 | Paladin Energy Corp. | Dallas, TX 75229 | Oil & Gas Operator | Jul 2017 |
| 494 | Pantera Energy Company | Amarillo, TX 79101 | Oil & Gas Operator | Oct 2025 |
| 495 | Par Development | Midland, TX 79711 | Oil & Gas Operator | Oct 2025 |
| 496 | Parish, John R. | Andrews, TX 79714 | Oil & Gas Operator | Oct 2025 |
| 497 | Patriot Resources, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 498 | Patterson Petroleum LLC | Snyder, TX 79550 | Oil & Gas Operator | Oct 2007 |
| 499 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 500 | Pcore Exploration & Prod II LLC | Golden, CO 80401 | Oil & Gas Operator | Jun 2020 |