| 401 | Orr Production Company | Austin, TX 78746 | Oil & Gas Operator | Dec 2000 |
| 402 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 403 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | Feb 2026 |
| 404 | Osyka Permian, LLC | Houston, TX 77079 | Oil & Gas Operator | Feb 2026 |
| 405 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Feb 2026 |
| 406 | Pace West Production LC | San Angelo, TX 76904 | Oil & Gas Operator | Sep 1995 |
| 407 | Padon, Frank B. Oil Oper., Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1998 |
| 408 | Paloma Operating, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 409 | Pantano Energy | San Antonio, TX 78258 | Oil & Gas Operator | Jul 1999 |
| 410 | Parker & Parsley Development L.P | Midland, TX 79702 | Oil & Gas Operator | Oct 2007 |
| 411 | Parker & Parsley Producing LP | Midland, TX 79702 | Oil & Gas Operator | Oct 1997 |
| 412 | Patriot Operating Company, Inc. | Houston, TX 77008 | Oil & Gas Operator | Sep 2003 |
| 413 | Patterson Petroleum LLC | Snyder, TX 79550 | Oil & Gas Operator | Oct 2007 |
| 414 | Patterson Petroleum LP | Snyder, TX 79550 | Oil & Gas Operator | Mar 2008 |
| 415 | Patterson Petroleum, Inc. | Snyder, TX 79550 | Oil & Gas Operator | Feb 2000 |
| 416 | Pearl, Bill H. Productions, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Feb 2026 |
| 417 | Pegasus Operating, Inc. | Coldspring, TX 77331 | Oil & Gas Operator | Feb 2026 |
| 418 | Pennzenergy Exp. & Prod., L.L.C. | Houston, TX 77210 | Oil & Gas Operator | Mar 2000 |
| 419 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 420 | Petex | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2026 |
| 421 | Petra Oleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 422 | Petro Vest, Inc. | Houston, TX 77046 | Oil & Gas Operator | Sep 2014 |
| 423 | Petro-Hunt Corporation | Dallas, TX 75201 | Oil & Gas Operator | Jun 2003 |
| 424 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 425 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | May 2025 |
| 426 | Petroglyph Operating Co | Boise, ID 83709 | Oil & Gas Operator | Jul 2017 |
| 427 | Petroleum Management, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Feb 2026 |
| 428 | Petropro Energy Partners, L.P. | Houston, TX 77024 | Oil & Gas Operator | Jan 2013 |
| 429 | PH Exploration, Inc. | Houston, TX 77008 | Oil & Gas Operator | Nov 2001 |
| 430 | Phere Operating Inc | Spring Branch, TX 78070 | Oil & Gas Operator | Feb 2026 |
| 431 | Phylko Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Aug 2003 |
| 432 | Pi Energy, Inc. | Wichita Falls, TX 76301 | Oil & Gas Operator | Feb 2026 |
| 433 | Pierce Junction Petroleum Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2010 |
| 434 | Pine Ridge Operating, L.P. | Waelder, TX 78959 | Oil & Gas Operator | Feb 2026 |
| 435 | Pintail Oil & Gas, LLC | Midland, TX 79702 | Oil & Gas Operator | Dec 2019 |
| 436 | Pintail Production Co., Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Feb 2026 |
| 437 | Pintex Operating Inc. | Corpus Chrsti, TX 78478 | Oil & Gas Operator | Feb 2005 |
| 438 | Pioneer Natural Res. USA, Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 439 | Pioneer Resources Producing, L.P | Irving, TX 75039 | Oil & Gas Operator | Feb 2001 |
| 440 | Pitchfork Oil & Gas, Inc. | Orchard, TX 77464 | Oil & Gas Operator | Feb 2026 |
| 441 | Placer Oil Co. | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2008 |
| 442 | Plains Marketing, LP | Cushing, OK 74023 | Oil Operator | Jan 2012 |
| 443 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 444 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 445 | Premier Minerals, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 446 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 447 | Prime Operating Company | Midland, TX 79705 | Oil & Gas Operator | Feb 2026 |
| 448 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 449 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Feb 2026 |
| 450 | Property Development Group, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Feb 2026 |
| 451 | Pure Resources, L.P. | Midland, TX 79701 | Oil & Gas Operator | Mar 2006 |
| 452 | Pyramid Energy Inc | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2012 |
| 453 | QNK Energy,Inc. | Alice, TX 78333 | Oil & Gas Operator | Aug 2016 |
| 454 | Rand Oil & Gas Corp. | Houston, TX 77040 | Oil & Gas Operator | Feb 2026 |
| 455 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 456 | Range Production Company, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2025 |
| 457 | Rawhide Operating, Inc. | New Braunfels, TX 78131 | Oil & Gas Operator | Feb 2026 |
| 458 | Rec Well Service, Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2008 |
| 459 | Redwood Operating, Inc. | Houston, TX 77058 | Oil & Gas Operator | Feb 2026 |
| 460 | Reef Exploration, Inc. (A-1) | Richardson, TX 75080 | Oil & Gas Operator | Oct 2006 |
| 461 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 462 | Rego Development Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2002 |
| 463 | Reh Energy, Inc. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Feb 2026 |
| 464 | Remora Management, LLC | The Woodlands, TX 77382 | Oil & Gas Operator | Feb 2026 |
| 465 | Remora Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 466 | Reserve Operating Corp. | Houston, TX 77040 | Oil & Gas Operator | Feb 2026 |
| 467 | Rife Oil Properties Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Feb 2026 |
| 468 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Feb 2026 |
| 469 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 470 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | Feb 2026 |
| 471 | Rodeo Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2024 |
| 472 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Feb 2026 |
| 473 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 474 | Rotation, Incorporated | Houston, TX 77057 | Oil & Gas Operator | Mar 2023 |
| 475 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 476 | Rutherford Oil Corporation | Houston, TX 77046 | Oil & Gas Operator | Jun 2019 |
| 477 | Ruwco Oil And Gas Corp. | Austin, TX 78701 | Oil & Gas Operator | Aug 2021 |
| 478 | S N D Energy Company, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Feb 2026 |
| 479 | Salida Exploration, LLC | Abilene, TX 79603 | Oil & Gas Operator | Feb 2026 |
| 480 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 481 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 482 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 483 | Sanchez Exploration Company LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2024 |
| 484 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 485 | Santa Fe Energy Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 486 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |
| 487 | Saxet Operating Co.,Inc. | Madisonville, TX 77864 | Oil & Gas Operator | Feb 2026 |
| 488 | Scope Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2003 |
| 489 | Scout Energy LTD Liability Co | Inez, TX 77968 | Oil & Gas Operator | Feb 2026 |
| 490 | Scully And Smith Oil Corporation | Salado, TX 76571 | Oil & Gas Operator | Feb 1995 |
| 491 | Scully Energy Corporation | Salado, TX 76571 | Oil & Gas Operator | Mar 2012 |
| 492 | Senora Resources, Inc. | Dime Box, TX 77853 | Oil & Gas Operator | Feb 2026 |
| 493 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 494 | Shana Petroleum Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2002 |
| 495 | Shanghai Energy Corporation | Houston, TX 77027 | Oil & Gas Operator | Apr 2003 |
| 496 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 497 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 498 | Shore Petroleum Corp. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 499 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Nov 2025 |
| 500 | Silverbrook Operating II LLC | Barker, TX 77413 | Oil & Gas Operator | Feb 2026 |