| 501 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 502 | Oily Dog Operators Texas, LLC | Austin, TX 78746 | Oil Operator | May 2024 |
| 503 | Olsan Brothers, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Apr 1994 |
| 504 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 505 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 506 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2024 |
| 507 | Ovation Energy, LP | N Richlnd HLS, TX 76180 | Oil & Gas Operator | Sep 2004 |
| 508 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | May 2024 |
| 509 | P. R. L. Oil Company | Albany, TX 76430 | Oil & Gas Operator | Apr 2008 |
| 510 | Palmer Petroleum Inc. | Shreveport, LA 71106 | Oil & Gas Operator | May 2024 |
| 511 | Palo Petroleum, Inc. | Dallas, TX 75360 | Oil & Gas Operator | May 2024 |
| 512 | Paradis Investments, L.L.C. | Bellaire, TX 77401 | Oil Operator | Jun 2020 |
| 513 | Park & Park Oil Co. | Allen, TX 75002 | Oil & Gas Operator | May 2024 |
| 514 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 515 | Patara Andover I LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 516 | Patara Oil & Gas LLC | Dallas, TX 75219 | Oil & Gas Operator | Mar 2018 |
| 517 | Patton Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Nov 1997 |
| 518 | Pawnee Oil And Gas, Inc. | Richardson, TX 75083 | Oil & Gas Operator | May 2023 |
| 519 | Peak Energy Corporation | Plano, TX 75093 | Oil & Gas Operator | Oct 2018 |
| 520 | Pearl Petroleum Inc | Lawton, OK 73501-5821 | Oil & Gas Operator | Jan 2014 |
| 521 | Pedernales Petroleum Op, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2024 |
| 522 | Pennant Dev. And Prod., LLC | Midland, TX 79702 | Oil Operator | May 2024 |
| 523 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 524 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 525 | Permian Natural Resources | Austin, TX 78701 | Oil & Gas Operator | May 2024 |
| 526 | Petralis Energy Resources, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2024 |
| 527 | Petro-Chem Operating Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | May 2024 |
| 528 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 529 | Petroreal Inc. | Temple, TX 76503 | Oil & Gas Operator | May 2024 |
| 530 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 531 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 532 | Phillips, B. F. Jr., Estate Of | Dallas, TX 75201 | Oil & Gas Operator | Mar 2011 |
| 533 | Phillips, Jack L. | Gladewater, TX 75647 | Oil & Gas Operator | Dec 1997 |
| 534 | Phillips, Jack L. Co. | Gladewater, TX 75647 | Oil & Gas Operator | May 2024 |
| 535 | Pine Oil Company | Cibolo, TX 78108 | Oil & Gas Operator | Dec 2022 |
| 536 | Pinewood Exploration Inc. | Arlington, TX 76096 | Oil & Gas Operator | Oct 2011 |
| 537 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 538 | Plains Marketing LP | Cushing, OK 74023 | Oil & Gas Operator | Dec 2022 |
| 539 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 540 | Ponta E&P LLP | Houston, TX 77057 | Oil & Gas Operator | May 2024 |
| 541 | Powell, Gene Investments, Inc. | Longview, TX 75608 | Oil & Gas Operator | May 2024 |
| 542 | Powell, N. P. Estate | Tyler, TX 75702 | Oil & Gas Operator | Aug 1997 |
| 543 | Powell, N. P. Estate Partnership | Tyler, TX 75702 | Oil & Gas Operator | May 2002 |
| 544 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | May 2024 |
| 545 | Praxis Energy, LLC | Midland, TX 79705 | Oil Operator | Apr 2002 |
| 546 | Preston Exploration LLC | Spring, TX 77387 | Oil & Gas Operator | Dec 2014 |
| 547 | Pride Exploration, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Aug 2015 |
| 548 | Princess Three Corporation | Henderson, TX 75653 | Oil & Gas Operator | Apr 2020 |
| 549 | Princess Three Operating, LLC | Henderson, TX 75653 | Oil & Gas Operator | May 2024 |
| 550 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 551 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | May 2024 |
| 552 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | May 2024 |
| 553 | Providence Oil & Gas Corp | Tulsa, OK 74135-5463 | Oil & Gas Operator | May 2005 |
| 554 | Psi Production, Inc. | Tyler, TX 75702 | Gas Operator | Jan 1994 |
| 555 | PXP Gulf Coast Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 556 | PXP Texas Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2007 |
| 557 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Jan 2024 |
| 558 | R & C Petroleum, Inc. | Flint, TX 75762 | Oil & Gas Operator | May 2024 |
| 559 | R2Q Operating LLC | Iowa Park, TX 76367 | Oil & Gas Operator | May 2024 |
| 560 | Radius Operating, LLC | Round Rock, TX 78664 | Oil & Gas Operator | May 2024 |
| 561 | Rainbow Resources, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2007 |
| 562 | Ram Operating Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Sep 2012 |
| 563 | Ramtex Energy LLC | Tulsa, OK 74152 | Oil & Gas Operator | May 2024 |
| 564 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 565 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 2024 |
| 566 | Ranger Investments, Inc. | Longview, TX 75605 | Oil & Gas Operator | Nov 2006 |
| 567 | Raydon Production Company | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 1992 |
| 568 | RBD-Shelby Agency | Dallas, TX 75283 | Oil & Gas Operator | Dec 1993 |
| 569 | Rebel Production Company | Kilgore, TX 75663 | Oil Operator | May 2024 |
| 570 | Recon Oil Co. | Emory, TX 75440 | Oil & Gas Operator | May 2024 |
| 571 | Redwood Oil & Gas | McKinney, TX 75070 | Oil & Gas Operator | Apr 2013 |
| 572 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 573 | Remuda Operating Company | Midland, TX 79711 | Oil & Gas Operator | May 2024 |
| 574 | Reostar Operating Incorporated | Fort Worth, TX 76107 | Oil & Gas Operator | Sep 2012 |
| 575 | Reserve Management, Inc. | Tyler, TX 75711 | Oil & Gas Operator | May 2024 |
| 576 | Reserve Production, Inc. | Tyler, TX 75713 | Oil & Gas Operator | Mar 2008 |
| 577 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 578 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | May 2024 |
| 579 | Rfe Operating, LLC | Tyler, TX 75703 | Oil & Gas Operator | May 2024 |
| 580 | RHC Energy (USA) LLC | Houston, TX 77027 | Oil Operator | May 2024 |
| 581 | Rheata Resources, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2024 |
| 582 | Richey Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | May 2024 |
| 583 | Richey Properties, Inc. | Tyler, TX 75711 | Oil & Gas Operator | May 2024 |
| 584 | Rig Runner Express Inc Of Texas | Kilgore, TX 75663 | Oil & Gas Operator | May 2014 |
| 585 | Rig Runner Express, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Mar 2008 |
| 586 | Riverstone Energy Operating, LLC | Houston, TX 77090 | Oil & Gas Operator | May 2024 |
| 587 | RLM Energy Company Inc. | Monroe, LA 71201 | Oil & Gas Operator | Mar 2008 |
| 588 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 589 | Rmor Production | Kilgore, TX 75662 | Oil Operator | May 2024 |
| 590 | Road Oil Sales Inc. | Tyler, TX 75711 | Oil Operator | Dec 1984 |
| 591 | Robbins Petroleum Corp. | Longview, TX 75606 | Oil & Gas Operator | Sep 1994 |
| 592 | Roberts & Hammack, Inc. | Dallas, TX 75206 | Oil & Gas Operator | May 2024 |
| 593 | Robertson Resources, Inc. | Midland, TX 79708 | Oil & Gas Operator | May 2024 |
| 594 | Robertson-Bryce Management, LLC | Tyler, TX 75701 | Oil & Gas Operator | May 2024 |
| 595 | Robinett Resources Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 1999 |
| 596 | Robinson Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Aug 2012 |
| 597 | Roc Operating, Inc. | Plano, TX 75093 | Oil & Gas Operator | Oct 2008 |
| 598 | Rockcliff Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | May 2024 |
| 599 | Rodessa Management, Inc. | Longview, TX 75606 | Oil & Gas Operator | May 1995 |
| 600 | Roil Mineral & Land Co. | Dallas, TX 75379 | Oil & Gas Operator | May 2024 |