| 401 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 402 | Mark IV Energy | San Antonio, TX 78213 | Oil & Gas Operator | Apr 1993 |
| 403 | Marquee Corporation | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 404 | Marwell Petroleum LTD Partnrship | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 405 | Marwell Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Apr 2006 |
| 406 | Masters Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2008 |
| 407 | Maverick Drilling Co., Inc. | Austin, TX 78729 | Oil & Gas Operator | Mar 2015 |
| 408 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 409 | Maverick Properties, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 1994 |
| 410 | Maxus Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Jan 1995 |
| 411 | Mayfield Engineering Service | Tulsa, OK 74104 | Oil & Gas Operator | Apr 2024 |
| 412 | Mayne & Mertz, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2013 |
| 413 | McCord Production, LTD. | Houston, TX 77002 | Gas Operator | Feb 1997 |
| 414 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Apr 2024 |
| 415 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 416 | McGuffin, Joe Jr. | Christoval, TX 76935 | Oil & Gas Operator | Apr 2024 |
| 417 | Mecom Energy Corporation | Houston, TX 77030 | Oil & Gas Operator | Jan 1999 |
| 418 | Mescalero Energy, Inc. | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 419 | Metco Oil Corporation | Seguin, TX 78155 | Oil Operator | Apr 2016 |
| 420 | Midstates Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2024 |
| 421 | Milagro Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Aug 2018 |
| 422 | Miller, W. C. Operating Company | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2024 |
| 423 | Mina Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2012 |
| 424 | Mission Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 425 | Mission River Systems, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Apr 2024 |
| 426 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 427 | Mobil Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2016 |
| 428 | Mobil Producing TX. & N.M. Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2024 |
| 429 | Modern Exploration, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Apr 2024 |
| 430 | Mogul Energy International, Inc. | Houston, TX 77042 | Oil & Gas Operator | Oct 2017 |
| 431 | Mohican Oil & Gas, L.L.C. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2013 |
| 432 | Mohican Operating, L.L.C. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2021 |
| 433 | Moose Oil & Gas Co. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 434 | Moose Operating Co., Inc. | Houston, TX 77006 | Oil & Gas Operator | Apr 2024 |
| 435 | Morris, W. Dale Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Apr 2024 |
| 436 | Mortimer Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2024 |
| 437 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2024 |
| 438 | Moy, Gary | Falls City, TX 78113 | Oil & Gas Operator | Nov 1998 |
| 439 | Mueller Engineering Corp. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Feb 2002 |
| 440 | Mueller Exploration, Inc. | Portland, TX 78374 | Oil & Gas Operator | Apr 2024 |
| 441 | Nadsoilco LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2024 |
| 442 | Ncey Holdings, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2013 |
| 443 | Nelson, James L. | Pettus, TX 78146 | Oil & Gas Operator | Apr 2024 |
| 444 | Neuhaus, V. F. Properties, Inc. | Palmhurst, TX 78573 | Oil & Gas Operator | Dec 2022 |
| 445 | Neumin Production Company | Point Comfort, TX 77978 | Oil & Gas Operator | Apr 2024 |
| 446 | New Source Oil & Gas, LLC | Victoria, TX 77903 | Oil & Gas Operator | Apr 2024 |
| 447 | Newton Corp.,The | Dallas, TX 75251 | Oil & Gas Operator | Apr 2024 |
| 448 | Nitro Oil & Gas, LLC | Midland, TX 79701 | Oil & Gas Operator | Apr 2024 |
| 449 | Noex, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Apr 1998 |
| 450 | Nog Production & Operating LLC | Goliad, TX 77963 | Oil & Gas Operator | Apr 2024 |
| 451 | Nomeco Oil & Gas Co. | Jackson, MI 49204 | Oil & Gas Operator | Dec 1994 |
| 452 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Apr 2024 |
| 453 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 454 | North Shore Energy, L.L.C. | Austin, TX 78750 | Oil & Gas Operator | Apr 2024 |
| 455 | NRG Assets Management, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2016 |
| 456 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | Apr 2024 |
| 457 | Oblaen Resources LLC | Wallis, TX 77485 | Oil & Gas Operator | Apr 2024 |
| 458 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 459 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 460 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 461 | Oldfield Acquisition LP | Austin, TX 78733 | Oil & Gas Operator | Sep 1996 |
| 462 | Olipdp II, LLC | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2024 |
| 463 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Apr 2024 |
| 464 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Apr 2024 |
| 465 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 466 | Osr Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Jul 2000 |
| 467 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | Apr 2024 |
| 468 | Outline Oil Company LLC | Beeville, TX 78104 | Oil Operator | Apr 2024 |
| 469 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Apr 2024 |
| 470 | Overly Operating Co. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 471 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Apr 2024 |
| 472 | Pace Oil And Gas Company | Austin, TX 78715 | Oil & Gas Operator | Apr 2024 |
| 473 | Pace West Production LC | San Angelo, TX 76904 | Oil & Gas Operator | Sep 1995 |
| 474 | Pacific Operators, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Mar 1999 |
| 475 | Palace Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2007 |
| 476 | Paleo Oil Company LLC | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Apr 2024 |
| 477 | Paloma Operating, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2024 |
| 478 | Pantano Energy | San Antonio, TX 78258 | Oil & Gas Operator | Jul 1999 |
| 479 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 480 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 481 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 482 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 483 | Patrick Pet. Corp. Of Michigan | Houston, TX 77227 | Oil & Gas Operator | Aug 1995 |
| 484 | Patterson Petroleum LLC | Snyder, TX 79550 | Oil & Gas Operator | Oct 2007 |
| 485 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 486 | Patterson, Ben M., Jr. | San Antonio, TX 78216 | Oil & Gas Operator | Mar 2003 |
| 487 | Pax Energy LTD | Elmhurst, IL 60126 | Oil & Gas Operator | Dec 1998 |
| 488 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Apr 2024 |
| 489 | Pegasus Operating, Inc. | Coldspring, TX 77331 | Oil & Gas Operator | Apr 2024 |
| 490 | Pegasus Petroleum Corporation | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Apr 2024 |
| 491 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 492 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 493 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Apr 2024 |
| 494 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 495 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 496 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 497 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Apr 2024 |
| 498 | Petropro Energy Partners, L.P. | Houston, TX 77024 | Oil & Gas Operator | Jan 2013 |
| 499 | Petrosearch Operating Co, LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2024 |
| 500 | Pgo, Inc. | Houston, TX 77042 | Oil & Gas Operator | Jun 1999 |