| 401 | Parker & Parsley Development Co. | Midland, TX 79702 | Oil & Gas Operator | May 1995 |
| 402 | Parker & Parsley Petroleum Co. | | Oil & Gas Operator | Dec 1990 |
| 403 | Partners Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Aug 1995 |
| 404 | Patrick Petroleum Corporation | | Oil & Gas Operator | Oct 1984 |
| 405 | Pel-Tex Oil Company, Inc. | | Oil & Gas Operator | Jul 1995 |
| 406 | Pel-Tex Oil Company, LLC | | Oil & Gas Operator | Nov 2010 |
| 407 | Pelto Oil Company | Houston, TX 77002 | Oil & Gas Operator | Nov 1998 |
| 408 | Pend Oreille Oil & Gas Company | | Oil & Gas Operator | Sep 1989 |
| 409 | Pennzenergy Explor & Prod LLC | | Oil & Gas Operator | Dec 1999 |
| 410 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 411 | Perdido Energy Louisiana, LLC | | Oil & Gas Operator | Dec 2024 |
| 412 | Peterman-Sturlese Et Al | | Oil & Gas Operator | Sep 1987 |
| 413 | Petro "E", LLC | | Oil & Gas Operator | Feb 2010 |
| 414 | Petro-Can, Inc. | | Oil & Gas Operator | Apr 1998 |
| 415 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 416 | Petrocorp | | Oil & Gas Operator | Nov 1992 |
| 417 | Petrocorp Incorporated | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2021 |
| 418 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | May 2025 |
| 419 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 420 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 421 | Petroleum Capital, L.C. | Dallas, TX 75367 | Oil & Gas Operator | Feb 2026 |
| 422 | Petroleum Exchange | | Oil & Gas Operator | Oct 1997 |
| 423 | Petroleum Resource MGMT Co TX | | Oil & Gas Operator | Sep 2020 |
| 424 | Phillips Oil Company | Casper, WY 82602 | Oil & Gas Operator | Sep 1986 |
| 425 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 426 | Phoenix Exploration Company LP | | Oil & Gas Operator | Sep 2011 |
| 427 | Phoenix Oil & Gas LTD., L.L.P. | Houston, TX 77010 | Oil & Gas Operator | Jun 2004 |
| 428 | Pioneer Exploration, LLC | Houston, TX 77090 | Oil & Gas Operator | Dec 2025 |
| 429 | Pioneer Exploration, LTD. | Houston, TX 77090 | Oil & Gas Operator | Sep 2008 |
| 430 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 431 | Polaris Enterprises Inc | Houston, TX 77057 | Oil & Gas Operator | Oct 1998 |
| 432 | Power Reserves, Inc. | | Oil Operator | Feb 1999 |
| 433 | Prayer Oil & Gas Production, LLC | Hallsville, TX 75650 | Oil & Gas Operator | Feb 2026 |
| 434 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 435 | Primary Fuels Inc | Midland, TX 79701-4410 | Oil & Gas Operator | Mar 1991 |
| 436 | Prospective Investment & Trding Co LTD | | Oil & Gas Operator | Sep 2012 |
| 437 | Q.E.D., Inc. | | Oil & Gas Operator | Dec 1987 |
| 438 | Quality Production SVC. LLC | | Oil & Gas Operator | Jul 2005 |
| 439 | Quinoco Petroleum Inc | | Oil & Gas Operator | Dec 1990 |
| 440 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 441 | Quintana Production Co. | | Oil & Gas Operator | Feb 1987 |
| 442 | Ray Conner | | Oil & Gas Operator | Apr 2002 |
| 443 | Rayville Resources, Inc. | | Oil & Gas Operator | Aug 1991 |
| 444 | Red Willow Offshore, LLC | | Oil & Gas Operator | Apr 2011 |
| 445 | Reef Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2007 |
| 446 | Reef Exploration, L.P. | Richardson, TX 75080 | Oil & Gas Operator | Feb 2026 |
| 447 | Resource Securities Corp. | | Oil & Gas Operator | Mar 2005 |
| 448 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 449 | Richard H. Lee, L.L.C. | | Oil & Gas Operator | Sep 1999 |
| 450 | Rimco Production Company, Inc. | | Oil & Gas Operator | Jan 2004 |
| 451 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 452 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 453 | Robertson Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 454 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Feb 2026 |
| 455 | Rosewood Resources Inc | Dallas, TX 75201 | Oil & Gas Operator | Feb 2026 |
| 456 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Feb 2026 |
| 457 | Rozel Operating Company | | Oil & Gas Operator | Oct 2014 |
| 458 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 459 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 460 | Sable Minerals, Inc. | | Oil & Gas Operator | Nov 1993 |
| 461 | Samedan Oil Corp. Et Al | | Oil & Gas Operator | Jan 1989 |
| 462 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 463 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 464 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 465 | Samuel Gary Jr. & Assoc., Inc. | | Oil & Gas Operator | Mar 2023 |
| 466 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 467 | Santa Fe Braun Inc | Dallas, TX 75240-6620 | Oil & Gas Operator | Mar 1995 |
| 468 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 469 | Seawide Limited | | Oil & Gas Operator | Jul 1983 |
| 470 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 471 | Shale Energy International, LLC | | Oil & Gas Operator | Nov 2024 |
| 472 | Shelf Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 473 | Shell Oil Co. | Houston, TX 77001 | Oil & Gas Operator | Jun 1985 |
| 474 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 475 | Shenandoah Oil Corporation | | Oil & Gas Operator | Jun 1979 |
| 476 | Shocker Energy, Inc. | | Oil & Gas Operator | Oct 1992 |
| 477 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 478 | Signal Petroleum | | Oil & Gas Operator | Jul 1980 |
| 479 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 480 | Skyline Oil Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Jan 1987 |
| 481 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 482 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 483 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 484 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 485 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Feb 2026 |
| 486 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 487 | South Leeville, LLC | Houston, TX 77069 | Oil & Gas Operator | Oct 2022 |
| 488 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 489 | Southern Petroleum Company | | Oil & Gas Operator | Jan 1994 |
| 490 | Southern Production SVC., Inc. | | Oil Operator | Mar 1997 |
| 491 | Southport Exploration Inc | Tulsa, OK 74103-4015 | Oil & Gas Operator | Nov 1998 |
| 492 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 493 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 494 | St. Mary Energy Company | Houston, TX 77079 | Oil & Gas Operator | Aug 2008 |
| 495 | Star Energy Inc | Dayton, PA 16222-4325 | Oil & Gas Operator | Dec 2025 |
| 496 | Stone Oil Corp & McMoran Expl | | Oil & Gas Operator | Oct 1984 |
| 497 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 498 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Feb 2026 |
| 499 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Feb 2026 |
| 500 | Sun Exploration And Production Co | | Oil & Gas Operator | Jan 1990 |