| 401 | Nicco Operating Co. | | Oil & Gas Operator | May 1990 |
| 402 | Nicklos Oil & Gas Co. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1986 |
| 403 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 404 | Nomeco Oil & Gas Co. | Jackson, MI 49204 | Oil & Gas Operator | Dec 1994 |
| 405 | Norcen Explorer, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 1998 |
| 406 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 407 | North Central Oil Corp., Et Al | | Oil & Gas Operator | Mar 1977 |
| 408 | Northcott Exploration Co. Inc. | | Oil & Gas Operator | Dec 1987 |
| 409 | Northern Michigan Expl Co | | Oil & Gas Operator | Jul 1990 |
| 410 | Nugulf Operating, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 411 | Ody Oil Corp. | | Oil & Gas Operator | Oct 1994 |
| 412 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 413 | Oleum Inc | | Oil & Gas Operator | Mar 1996 |
| 414 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 415 | Oleum Operating La LLC | | Oil & Gas Operator | Nov 2022 |
| 416 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 417 | Oracle Oil, LLC | | Oil & Gas Operator | Jul 2013 |
| 418 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 419 | Oxy Petroleum Inc | | Oil & Gas Operator | Jan 1986 |
| 420 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2025 |
| 421 | P & P Producing Inc | Midland, TX 79702 | Oil & Gas Operator | Feb 2015 |
| 422 | P D Parker | | Oil & Gas Operator | Aug 1985 |
| 423 | Pacific Enterprises Oil Co USA | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 424 | Palmer Petroleum, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jun 2025 |
| 425 | Pan-Ok Production Company | | Oil & Gas Operator | Nov 2024 |
| 426 | Panther Bayou Energy, LLC | Houston, TX 77070 | Oil & Gas Operator | Apr 2021 |
| 427 | Parker & Parsley Devpt L P | | Oil & Gas Operator | Oct 1997 |
| 428 | Paul M. Toce | | Oil & Gas Operator | Jul 1984 |
| 429 | Peak Operating Co. | | Oil & Gas Operator | Jul 2024 |
| 430 | Pecos Petroleum Company | Houston, TX 77057 | Oil & Gas Operator | Oct 1999 |
| 431 | Pel-Tex Oil Company, Inc. | | Oil & Gas Operator | Jul 1995 |
| 432 | Pennington Operating Company, LLC | | Oil & Gas Operator | Jul 2020 |
| 433 | Pennzenergy Explor & Prod LLC | | Oil & Gas Operator | Dec 1999 |
| 434 | Pennzoil Exploration & Production Co. | Carthage, TX 75633 | Oil & Gas Operator | Mar 2008 |
| 435 | Pennzoil Petroleum Company | Houston, TX 77252 | Oil & Gas Operator | Nov 1999 |
| 436 | Peoples Energy Prod.-TX, L.P. | Houston, TX 77002 | Oil & Gas Operator | Sep 2007 |
| 437 | Perdido Energy Louisiana, LLC | | Oil & Gas Operator | Dec 2024 |
| 438 | Petro "E", LLC | | Oil & Gas Operator | Feb 2010 |
| 439 | Petro Harvester Operating Company, LLC | | Oil & Gas Operator | Nov 2022 |
| 440 | Petro Ventures Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2019 |
| 441 | Petro-Hunt, L.L.C. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2025 |
| 442 | Petro-Lewis Corp. | | Oil & Gas Operator | Feb 1994 |
| 443 | Petrodome Operating, LLC | Houston, TX 77265 | Oil & Gas Operator | Jun 2025 |
| 444 | Petrogulf Corporation | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 445 | Petrohawk Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2021 |
| 446 | Petroleum Corp Of Delaware The | | Oil & Gas Operator | May 1991 |
| 447 | Petroleum Engineers, Inc. | | Oil & Gas Operator | Jun 1983 |
| 448 | Petroleum Exchange | | Oil & Gas Operator | Oct 1997 |
| 449 | Petroleum Properties MGMT Corp | | Oil & Gas Operator | Aug 1990 |
| 450 | Petroleum Resources MGMT Corp. | | Oil & Gas Operator | Mar 2002 |
| 451 | Petroquest Energy, L.L.C. | Lafayette, LA 70505 | Oil & Gas Operator | Dec 2025 |
| 452 | PG&E Resources Company | Houston, TX 77042 | Oil & Gas Operator | May 1995 |
| 453 | Pharaoh Oil & Gas, Inc. | MC Camey, TX 79752 | Oil & Gas Operator | Dec 2025 |
| 454 | Phillips Oil Company | Casper, WY 82602 | Oil & Gas Operator | Sep 1986 |
| 455 | Phillips Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Mar 2013 |
| 456 | Phoenix Exploration Company LP | | Oil & Gas Operator | Sep 2011 |
| 457 | Pickens Company, Inc., The | Dallas, TX 75225 | Oil & Gas Operator | Jan 2025 |
| 458 | Pioneer Exploration Company | Houston, TX 77090 | Oil & Gas Operator | Sep 2025 |
| 459 | Pioneer Exploration, LLC | Houston, TX 77090 | Oil & Gas Operator | Oct 2025 |
| 460 | Pioneer Exploration, LTD. | Houston, TX 77090 | Oil & Gas Operator | Sep 2008 |
| 461 | Placid Oil Company | Houston, TX 77227 | Oil & Gas Operator | Mar 2008 |
| 462 | Plains Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2008 |
| 463 | Plano Corp. | | Oil & Gas Operator | Mar 2005 |
| 464 | Pledger West Broussard Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 465 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 466 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 467 | Power Reserves, Inc. | | Oil Operator | Feb 1999 |
| 468 | Prayer Oil & Gas Production, LLC | Hallsville, TX 75650 | Oil & Gas Operator | Dec 2025 |
| 469 | Precision Holdings, LLC | | Oil & Gas Operator | Dec 2015 |
| 470 | Presidio Energy Inc | | Oil & Gas Operator | Jan 1992 |
| 471 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 472 | Proton Energy, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2005 |
| 473 | Quarles Drilling Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2008 |
| 474 | Quest Exploration L.L.C. | | Oil & Gas Operator | Jul 2014 |
| 475 | Quinoco Petroleum Inc | | Oil & Gas Operator | Dec 1990 |
| 476 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 477 | R & B Oil Company, LLC Of Texas | | Oil & Gas Operator | Jan 2025 |
| 478 | R&R Resources Corporation | Houston, TX 77056 | Oil & Gas Operator | Dec 2015 |
| 479 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 480 | Ranger Holdings Co | | Oil & Gas Operator | Jul 1993 |
| 481 | Ranger Oil Company | Canada, 00100 | Oil & Gas Operator | Sep 2001 |
| 482 | Ranger, Inc. | | Oil & Gas Operator | Dec 1986 |
| 483 | Redman Operating Company | Houston, TX 77042 | Oil & Gas Operator | May 2008 |
| 484 | Reef Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2007 |
| 485 | Reef Exploration, L.P. | Richardson, TX 75080 | Oil & Gas Operator | Dec 2025 |
| 486 | Republic Mineral Corporation | | Oil & Gas Operator | Sep 1987 |
| 487 | Reserve Partners L.L.C. | | Oil & Gas Operator | Feb 2001 |
| 488 | Resource Acquisitions Corp. | | Oil & Gas Operator | Dec 2002 |
| 489 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 490 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 491 | Rock Energy Operating Company | | Oil & Gas Operator | Nov 2008 |
| 492 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 493 | Rozel Operating Company | | Oil & Gas Operator | Oct 2014 |
| 494 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 495 | Sabine Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 1996 |
| 496 | Sam Jones & Assoc Prod Div Inc | | Oil & Gas Operator | Feb 1999 |
| 497 | Samedan Oil Corp. Et Al | | Oil & Gas Operator | Jan 1989 |
| 498 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 499 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 500 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2025 |