| 501 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 502 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 503 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 504 | Omar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 505 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 506 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 507 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2026 |
| 508 | Otb Operating, LLC | Stanton, TX 79782 | Oil & Gas Operator | Sep 2026 |
| 509 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | May 2026 |
| 510 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2026 |
| 511 | Owl Operating Ventures L.L.C. | Midland, TX 79708 | Oil & Gas Operator | Dec 2022 |
| 512 | Owl Ops LLC | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 513 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Sep 2026 |
| 514 | Oxyrock Operating, LLC | Houston, TX 77046 | Oil & Gas Operator | Sep 2026 |
| 515 | Ozark Exploration, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Sep 2026 |
| 516 | P-R-O Management, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Sep 2026 |
| 517 | P4 Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 518 | Pacific Enterprises Royalty Co | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 519 | Paladin Petroleum III, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 520 | Palo Petroleum, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 521 | Paloma Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 522 | Pangea Corporation | San Angelo, TX 76904 | Oil & Gas Operator | Sep 2026 |
| 523 | Panhandle Oil & Gas Inc | Oklahoma City, OK 73112-5688 | Oil & Gas Operator | May 2007 |
| 524 | Parallel Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Jan 2010 |
| 525 | Parapetroleum | Kerrville, TX 78028 | Oil & Gas Operator | Feb 1997 |
| 526 | Parker & Parsley Acq. Group LLC | Midland, TX 79702 | Oil & Gas Operator | Aug 2002 |
| 527 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 528 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 529 | Parker & Parsley Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Nov 2000 |
| 530 | Parsley Energy Operations, LLC | Irving, TX 75038 | Oil & Gas Operator | Jan 2021 |
| 531 | Partee Drilling Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Sep 2026 |
| 532 | Pathfinder Exploration LLC | Norman, OK 73069-8516 | Gas Operator | Aug 2003 |
| 533 | Patrick Exploration Company | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 534 | Patriot Resources, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 535 | Patriot Services, Inc. | Westbrook, TX 79565 | Oil & Gas Operator | Mar 2008 |
| 536 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 537 | Patterson Petroleum, Inc. | Snyder, TX 79550 | Oil & Gas Operator | Feb 2000 |
| 538 | PDC Energy | Denver, CO 80203 | Oil & Gas Operator | Nov 2012 |
| 539 | PDC-WV-Co Corporation | Denver, CO 80203 | Oil & Gas Operator | Aug 2010 |
| 540 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Sep 2026 |
| 541 | Pecos River Exploration, LLC | Allen, TX 75013 | Oil & Gas Operator | Jun 2025 |
| 542 | Ped Oil Corporation | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 543 | Penergy | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 544 | Perimeter Resource Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 545 | Permian Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 546 | Permian West Corp. | Odessa, TX 79762 | Oil & Gas Operator | Sep 2026 |
| 547 | Perry Producing Company, Inc. | Ackerly, TX 79713 | Oil & Gas Operator | Sep 2026 |
| 548 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Sep 2026 |
| 549 | Petroleum Technical Services Co. | Midland, TX 79707 | Oil & Gas Operator | Dec 2004 |
| 550 | Petroplex Energy Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 551 | Petroplex Equipment, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2019 |
| 552 | Petrosource Energy Corporation | Fort Worth, TX 76112 | Oil & Gas Operator | Sep 2026 |
| 553 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 554 | Pharaoh Oil & Gas, Inc. | MC Camey, TX 79752 | Oil & Gas Operator | Sep 2026 |
| 555 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 556 | Pinon Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2023 |
| 557 | Pintail Production Co., Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Sep 2026 |
| 558 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 559 | Pitco Investments, LTD. | Scottsdale, AZ 85261 | Oil & Gas Operator | Jan 2013 |
| 560 | Pitts Energy Co. | Midland, TX 79707 | Oil & Gas Operator | Sep 2026 |
| 561 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 562 | Plains Production Inc | Wichita Falls, TX 76308 | Oil & Gas Operator | Dec 1995 |
| 563 | Platform Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 564 | Platinum Exploration Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 565 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 566 | Pontotoc Oil Corp. | Midland, TX 79702 | Oil & Gas Operator | Feb 1996 |
| 567 | Premier Natural Resources, L.P. | Tulsa, OK 74105 | Oil & Gas Operator | Feb 2007 |
| 568 | Premier Natural Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2026 |
| 569 | Prensorus Energy, LLC | Abilene, TX 79604 | Oil & Gas Operator | Sep 2026 |
| 570 | Primal Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2026 |
| 571 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 572 | Probe Exploration Company | Abilene, TX 79605 | Oil & Gas Operator | Sep 2026 |
| 573 | Probity Operating, LLC | Midland, TX 79708 | Oil & Gas Operator | Jul 2014 |
| 574 | PSP Operating, Inc. | Lubbock, TX 79413 | Oil & Gas Operator | Jun 1999 |
| 575 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 576 | Qep Energy Company | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 577 | QP, Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 578 | Qstar Operating LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 2016 |
| 579 | Quail Operating, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Sep 2026 |
| 580 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | May 2026 |
| 581 | Quay Valley, Inc. | Midland, TX 79710 | Oil & Gas Operator | Oct 2007 |
| 582 | Quest Energies Group,LTD. | Shreveport, LA 71106 | Oil & Gas Operator | Mar 1997 |
| 583 | Questar Expl. And Prod. Co. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jul 2011 |
| 584 | R & C Oil Company LLC | Westbrook, TX 79565 | Oil Operator | Sep 2026 |
| 585 | R K Petroleum Corp. | Midland, TX 79708 | Oil & Gas Operator | May 2024 |
| 586 | R. K. G. Engineering, Inc. | Odessa, TX 79760 | Oil & Gas Operator | Sep 2026 |
| 587 | Ram Operating Inc. | Browns, IL 62818 | Oil & Gas Operator | Aug 2008 |
| 588 | Rangeland Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2002 |
| 589 | Ranphil, LLC | Hiltn Head Is, SC 29928 | Oil & Gas Operator | Feb 2016 |
| 590 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 591 | Rasmussen, Tom | San Angelo, TX 76904 | Oil & Gas Operator | Sep 2026 |
| 592 | Rattler Midstream Operating LLC | Midland, TX 79701 | Oil Operator | Sep 2026 |
| 593 | Raw Oil & Gas, Inc. | Lubbock, TX 79401 | Oil & Gas Operator | Sep 2026 |
| 594 | RBJ & Associates, LP | Midland, TX 79707 | Oil Operator | Jan 2020 |
| 595 | RCW Oil Company | Forsan, TX 79733 | Oil & Gas Operator | Mar 2019 |
| 596 | RCW Oil, LLC | Forsan, TX 79733 | Oil & Gas Operator | Sep 2026 |
| 597 | Reach Oil And Gas Company Inc | Oklahoma City, OK 73118-1100 | Oil & Gas Operator | May 2026 |
| 598 | Reatta Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2026 |
| 599 | Red Highland Resources LLC | Houston, TX 77063 | Oil & Gas Operator | Sep 2026 |
| 600 | Red Hills Energy, LLC | Medicine Lodge, KS 67104 | Oil & Gas Operator | Apr 2026 |