| 501 | Oden, Robin H., Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 1994 |
| 502 | Ogris Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 503 | Ogs Operating Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2008 |
| 504 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Oct 2025 |
| 505 | Ojb, Inc. | Buda, TX 78610 | Oil & Gas Operator | Mar 2013 |
| 506 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 507 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 508 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Oct 2025 |
| 509 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 510 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 511 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2025 |
| 512 | Osborn,W.B. Oil & Gas Operations | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 513 | Otb Operating, LLC | Stanton, TX 79782 | Oil & Gas Operator | Oct 2025 |
| 514 | Overton Park Oil & Gas LP | Fort Worth, TX 76109 | Oil & Gas Operator | Oct 2025 |
| 515 | Owens Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 516 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 517 | Oxy USA WTP LP | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
| 518 | Oz Gas Corporation | Austin, TX 78746 | Gas Operator | Oct 2025 |
| 519 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 520 | Oztx Oil & Gas, L.L.C. | Ozona, TX 76943 | Oil & Gas Operator | Oct 2025 |
| 521 | P,B&B Operating Inc. | Coleman, TX 76834 | Oil & Gas Operator | Oct 2025 |
| 522 | P1 Energy, LLC | Judson, TX 75660 | Oil & Gas Operator | Oct 2025 |
| 523 | Pace Oil And Gas Company | Austin, TX 78715 | Oil & Gas Operator | Oct 2025 |
| 524 | Page Energy | Eldorado, TX 76936 | Oil & Gas Operator | Mar 1997 |
| 525 | Page Oil & Gas, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 526 | Palo Petroleum, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Oct 2025 |
| 527 | Panada Exploration, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Jun 1996 |
| 528 | Panhandle Oil & Gas Inc | Oklahoma City, OK 73112-5688 | Oil & Gas Operator | May 2007 |
| 529 | Parallel Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Jan 2010 |
| 530 | Parallel Petroleum LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 531 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 532 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 533 | Patina Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2016 |
| 534 | Patno Oil & Gas Company | Zapata, TX 78076 | Oil & Gas Operator | Oct 2025 |
| 535 | Patrick Pet. Corp. Of Michigan | Houston, TX 77227 | Oil & Gas Operator | Aug 1995 |
| 536 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 537 | Pbex Operations, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 538 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Oct 2025 |
| 539 | Pech Oil Co., No. 2 | Midland, TX 79702 | Oil & Gas Operator | Apr 2013 |
| 540 | Pecos Valley Management Co. | Dallas, TX 75206 | Oil & Gas Operator | Aug 2008 |
| 541 | Pedeco, Inc. | Casper, WY 82601 | Oil & Gas Operator | Mar 2008 |
| 542 | Penergy | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 543 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 544 | Pennzoil Petroleum Company | Houston, TX 77252 | Oil & Gas Operator | Nov 1999 |
| 545 | Perdido Energy, LLC | Houston, TX 77251 | Oil & Gas Operator | Oct 2025 |
| 546 | Perimeter Resource Company | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 547 | Permian Resources Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 548 | Permian Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 549 | Permian Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2018 |
| 550 | Permian Services Co., LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 551 | Permian West Corp. | Odessa, TX 79762 | Oil & Gas Operator | Oct 2025 |
| 552 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2025 |
| 553 | Petro-Smith Operating LLC | Houston, TX 77010 | Oil & Gas Operator | Oct 2025 |
| 554 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 555 | Petroleum Technical Services Co. | Midland, TX 79707 | Oil & Gas Operator | Dec 2004 |
| 556 | Petroplex Equipment, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2019 |
| 557 | Petx Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 558 | Pharaoh Oil & Gas, Inc. | MC Camey, TX 79752 | Oil & Gas Operator | Oct 2025 |
| 559 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 560 | Piedra Operating, LLC | Denver, CO 80202 | Oil & Gas Operator | May 2023 |
| 561 | Pinon Petroleum, Inc. | San Angelo, TX 76903 | Oil & Gas Operator | Apr 2004 |
| 562 | Pioneer Exploration Company | Houston, TX 77090 | Oil & Gas Operator | Jul 2025 |
| 563 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 564 | Pipeline Resources, Inc. | Corpus Chrsti, TX 78412 | Gas Operator | Aug 2003 |
| 565 | Pitts Energy Co. | Midland, TX 79707 | Oil & Gas Operator | Oct 2025 |
| 566 | Plains Exploration & Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Jul 2013 |
| 567 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 568 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 569 | Platinum Exploration Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 570 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 571 | Pogo Producing Company LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 572 | Polaris Production Corp. | Midland, TX 79702 | Oil & Gas Operator | Jan 2024 |
| 573 | Pontotoc Oil Corp. | Midland, TX 79702 | Oil & Gas Operator | Feb 1996 |
| 574 | Praxis Energy, LLC | Midland, TX 79705 | Oil Operator | Apr 2002 |
| 575 | Prestco, LLC | Ozona, TX 76943 | Oil & Gas Operator | Mar 2025 |
| 576 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2025 |
| 577 | Primal Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 578 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 579 | Primero Operating, Inc. | Roswell, NM 88202 | Oil & Gas Operator | Jun 2022 |
| 580 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 581 | Probity Operating, LLC | Midland, TX 79708 | Oil & Gas Operator | Jul 2014 |
| 582 | Production Gathering Company, LP | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 583 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Oct 2025 |
| 584 | Progas Properties, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Oct 2025 |
| 585 | Propel Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Sep 2013 |
| 586 | Prosper Oil & Gas,Inc. | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 587 | PT Petroleum, LLC | Argyle, TX 76226 | Oil & Gas Operator | Oct 2019 |
| 588 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 589 | PXP Texas Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2007 |
| 590 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 591 | Quail Ridge Petroleum LLC | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 592 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Jun 2025 |
| 593 | Quatro Oil And Gas, Inc. | Joshua, TX 76058 | Oil & Gas Operator | Oct 2025 |
| 594 | Quay Valley, Inc. | Midland, TX 79710 | Oil & Gas Operator | Oct 2007 |
| 595 | Questa Oil & Gas Co. | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2015 |
| 596 | R K Petroleum Corp. | Midland, TX 79708 | Oil & Gas Operator | May 2024 |
| 597 | R. K. G. Engineering, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Oct 2025 |
| 598 | Rad Oil Company | Snyder, TX 79549 | Oil & Gas Operator | Oct 2025 |
| 599 | Ram Operating Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Sep 2012 |
| 600 | Ram Operating Inc. | Browns, IL 62818 | Oil & Gas Operator | Aug 2008 |