| 501 | Lynn Creek Oil Company | Allen, TX 75002 | Oil & Gas Operator | Apr 2020 |
| 502 | Lynn Creek Oil Partnership, II | Dallas, TX 75243 | Oil & Gas Operator | Oct 2003 |
| 503 | Lynn Creek Production Company | Allen, TX 75002 | Oil & Gas Operator | Dec 2011 |
| 504 | Lynx Oil Co., Inc. | Denton, TX 76207 | Oil & Gas Operator | Sep 2003 |
| 505 | Lynx Operating Co., Inc. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2026 |
| 506 | Lyon Operating Company Inc.(Iii) | Jacksboro, TX 76458 | Oil & Gas Operator | Jun 2026 |
| 507 | M & A Oil Company, LTD. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jun 2026 |
| 508 | M-B Operating Co., Inc. | Rowlett, TX 75030 | Oil & Gas Operator | Jun 2026 |
| 509 | Maddox Operating | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 510 | Maguire Oil Company | Dallas, TX 75270 | Oil & Gas Operator | Mar 2015 |
| 511 | Mammoth Operating LLC | Spicewood, TX 78669 | Oil Operator | Jun 2026 |
| 512 | Maralo, Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 1998 |
| 513 | Marchman, J. E. | Graham, TX 76450 | Oil & Gas Operator | Jul 2009 |
| 514 | Marcon Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Oct 2011 |
| 515 | Marrow, N. S. | Austin, TX 78703 | Oil & Gas Operator | Aug 2012 |
| 516 | Marshall, Sam | Granbury, TX 76048 | Oil & Gas Operator | Aug 2010 |
| 517 | Marshall, Samuel Meek, Estate Of | Granbury, TX 76048 | Oil & Gas Operator | Jun 2026 |
| 518 | Martin & Richards Oil Co. | Jacksboro, TX 76458 | Oil & Gas Operator | Jul 1995 |
| 519 | Martin Bros. Oil | Graham, TX 76450 | Oil & Gas Operator | Dec 1993 |
| 520 | Martin Petroleum Corp. | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 521 | Martin Well Service | Graham, TX 76450 | Oil & Gas Operator | Jun 2015 |
| 522 | Martin, John I. | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 523 | Martin, Tim | Wichita Falls, TX 76302 | Oil & Gas Operator | Oct 2003 |
| 524 | Marwell Petroleum LTD Partnrship | Houston, TX 77027 | Oil & Gas Operator | Jun 2026 |
| 525 | Mash Oilfield Services, LP | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 526 | Mattox, J. R. | Jacksboro, TX 76458 | Oil Operator | Mar 2018 |
| 527 | Mayco Oil | Nocona, TX 76255 | Oil & Gas Operator | Jun 2026 |
| 528 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Jun 2026 |
| 529 | Maynard Oil Co. | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 530 | Mayo, Eddie | Fredericksbrg, TX 78624 | Oil & Gas Operator | Jun 2026 |
| 531 | MB Operating | Wichita Falls, TX 76309 | Oil & Gas Operator | Mar 2008 |
| 532 | McClymond, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2001 |
| 533 | McClymond, LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2009 |
| 534 | McCommons Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2026 |
| 535 | McCormick Operating, L.L.C. | Olney, TX 76374 | Oil Operator | Sep 2015 |
| 536 | McCracken, H. L. Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Jun 2026 |
| 537 | McCutchin Petroleum Corporation | Dallas, TX 75225 | Oil & Gas Operator | Jun 2026 |
| 538 | McDay Energy Corp. | Plano, TX 75024 | Oil & Gas Operator | Jun 2026 |
| 539 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 540 | McEuen, Billy Oil Co. | Bowie, TX 76230 | Oil & Gas Operator | Dec 2016 |
| 541 | McEver Oil Company Inc. | Austin, TX 78789 | Oil & Gas Operator | Mar 2008 |
| 542 | MCG Oil & Gas Operating, LLC | Archer City, TX 76351 | Oil & Gas Operator | Sep 2023 |
| 543 | McKee, Kenneth W. Oil Co. | Graham, TX 76450 | Oil & Gas Operator | Aug 2011 |
| 544 | McMahon-Bullington Drilling Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 1996 |
| 545 | McMahon-Bullington LP | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2009 |
| 546 | Meeker, Dan Management, Inc. | Fort Worth, TX 76107 | Oil & Gas Operator | Aug 2007 |
| 547 | Melrose Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Sep 2011 |
| 548 | Menasco, J. | Wichita Falls, TX 76310 | Oil & Gas Operator | Dec 2019 |
| 549 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Jun 2026 |
| 550 | MHM Oil Co. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2002 |
| 551 | MHM Pipeline Co., Inc. | Dallas, TX 75252 | Oil & Gas Operator | Jun 2026 |
| 552 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 553 | Miles Production Co. | Argyle, TX 76226 | Oil & Gas Operator | Mar 2008 |
| 554 | Miller, Bob I. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 555 | Mills Oil & Gas | Jacksboro, TX 76458 | Oil & Gas Operator | Mar 2008 |
| 556 | Mitchell Energy Company L.P. | Spring, TX 77387 | Oil & Gas Operator | Mar 2008 |
| 557 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 558 | MKS Consulting Corporation | Weatherford, TX 76086 | Oil & Gas Operator | Jul 2005 |
| 559 | MKS Natural Gas Company | Weatherford, TX 76086 | Oil & Gas Operator | Mar 2016 |
| 560 | Mna Enterprises LTD. Co. | Hobbs, NM 88242 | Oil & Gas Operator | Jan 2026 |
| 561 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 2007 |
| 562 | Mobil Petro Vac, Inc. | Duncan, OK 73533 | Oil & Gas Operator | Jun 2026 |
| 563 | Mobile Petrovac, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Jun 2026 |
| 564 | Mohican Exploration, LLC | Graham, TX 76450 | Oil & Gas Operator | Oct 2024 |
| 565 | Mokan Capital, LLC | Spicewood, TX 78669 | Oil Operator | Jun 2026 |
| 566 | Moller, Herbert T. | Wichita Falls, TX 76301 | Oil & Gas Operator | Aug 2003 |
| 567 | Moore, Stephen Operating | Graham, TX 76450 | Oil & Gas Operator | Jun 2002 |
| 568 | Morgan, C. V. Partnership | Olney, TX 76374 | Oil & Gas Operator | Jan 2009 |
| 569 | Moriah Resources, Inc. | Midland, TX 79704 | Oil & Gas Operator | Mar 2008 |
| 570 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2026 |
| 571 | Mosaic Oil LLC | Dallas, TX 75205 | Oil & Gas Operator | Jun 2026 |
| 572 | Mosaic Texas LLC | Dallas, TX 75205 | Oil & Gas Operator | Jun 2026 |
| 573 | Mote Resources, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Dec 2004 |
| 574 | Mountain Creek Oil Company, Inc. | Saint Jo, TX 76265 | Oil & Gas Operator | Jun 2026 |
| 575 | Mullin, W. B. | Graham, TX 76450 | Oil & Gas Operator | Sep 1998 |
| 576 | Munson, David M. Inc. | Dallas, TX 75251 | Oil & Gas Operator | Jun 2026 |
| 577 | Murjo Oil & Royalty Company | Fort Worth, TX 76121 | Oil & Gas Operator | Dec 2019 |
| 578 | Myers, A. J. | Jacksboro, TX 76458 | Oil & Gas Operator | Jun 2026 |
| 579 | N. E. Operating Co., Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2013 |
| 580 | Nall Oil & Gas | Mineral Wells, TX 76067 | Oil & Gas Operator | Jun 2026 |
| 581 | Natural Petroleum Company | Overton, TX 75684 | Oil & Gas Operator | Jun 1994 |
| 582 | Nautilus Exploration, Inc. | Farmers BRNCH, TX 75234 | Oil & Gas Operator | Nov 2021 |
| 583 | New Era International | Graham, TX 76450 | Oil & Gas Operator | Sep 2017 |
| 584 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Jun 2026 |
| 585 | Newark E&P Operating, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2017 |
| 586 | Newark Energy LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2011 |
| 587 | Newberry, Charles D Inc | Campbellsvlle, KY 42719 | Oil Operator | Jun 2026 |
| 588 | NHRG Inc | Wichita Falls, TX 76308 | Oil Operator | Jun 2026 |
| 589 | Nichols,Edwin S Explorations Inc | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 590 | Nitschke, Dan E. | Henrietta, TX 76365 | Oil & Gas Operator | Jun 2026 |
| 591 | Nordan Oil & Gas Corporation | Abilene, TX 79604 | Oil & Gas Operator | Feb 2018 |
| 592 | North Central Texas Energy LLC | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 593 | North Texas Plugging, LLC | Denton, TX 76205 | Oil & Gas Operator | Jun 2026 |
| 594 | Northridge Exploration, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2026 |
| 595 | Northridge Oil Company | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2026 |
| 596 | Northwest Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Jun 2014 |
| 597 | NT Minerals, LLC | Tulsa, OK 74172 | Oil & Gas Operator | Jun 2026 |
| 598 | Nytex Petroleum, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2014 |
| 599 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Jun 2026 |
| 600 | Oakmont Oil And Gas | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |