| 401 | PXP Louisiana L.L.C. | | Oil & Gas Operator | Nov 2010 |
| 402 | Pyro Energy Corp | Kingwood, TX 77339-2102 | Oil & Gas Operator | Mar 1998 |
| 403 | Quest Exploration L.L.C. | | Oil & Gas Operator | Jul 2014 |
| 404 | Quintana Petroleum Corporation | Denver, CO 80265 | Oil & Gas Operator | Mar 1998 |
| 405 | Quintana Production Co. | | Oil & Gas Operator | Feb 1987 |
| 406 | R&R Resources Corporation | Houston, TX 77056 | Oil & Gas Operator | Dec 2015 |
| 407 | R. L. Burns Corp. | | Oil & Gas Operator | Feb 1982 |
| 408 | R360 Environmental Solutions Of La, LLC | | Oil Operator | Jan 2025 |
| 409 | Ram Operating Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Sep 2012 |
| 410 | Rapiere Resources Company | | Oil & Gas Operator | Aug 2024 |
| 411 | Reagan Exploration Company Inc | | Oil & Gas Operator | Nov 1998 |
| 412 | Red Rock Energy Group Inc | | Oil & Gas Operator | Dec 2024 |
| 413 | Renaissance Petroleum Co LLC | Houston, TX 77058 | Oil & Gas Operator | Nov 2011 |
| 414 | Resource Development, Inc. | Stroud, OK 74079 | Oil & Gas Operator | Feb 2007 |
| 415 | Resource Securities Corp. | | Oil & Gas Operator | Mar 2005 |
| 416 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 417 | Roberts & Bunch Resources | | Oil & Gas Operator | Dec 1993 |
| 418 | Robertson Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 419 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 420 | Rollar Oil Co., Inc. | | Oil & Gas Operator | Jul 1999 |
| 421 | Rovig Minerals, Inc. | | Oil & Gas Operator | May 2020 |
| 422 | Roy M. Huffington, Inc. | | Oil & Gas Operator | Jul 1983 |
| 423 | Royalty Management & Dev Corp. | | Oil & Gas Operator | Apr 1998 |
| 424 | Rvo Petroleum Co. | | Oil & Gas Operator | Feb 1982 |
| 425 | S. Parish Oil Company, Inc. | | Oil & Gas Operator | Dec 1997 |
| 426 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 427 | Sabine Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 1996 |
| 428 | Sam Jones & Assoc Prod Div Inc | | Oil & Gas Operator | Feb 1999 |
| 429 | Sam Myers | | Oil & Gas Operator | Nov 1988 |
| 430 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 431 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | Jan 2025 |
| 432 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 433 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Mar 2025 |
| 434 | Sandridge Onshore, LLC | Houston, TX 77010 | Oil & Gas Operator | Jun 2014 |
| 435 | Sante Fe Minerals | | Oil & Gas Operator | Dec 1987 |
| 436 | SBM Operating Company Inc. | | Gas Operator | Sep 1997 |
| 437 | Se USA Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 438 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 439 | Seahawk Oil & Gas Company | Dallas, TX 75379 | Oil & Gas Operator | Aug 2007 |
| 440 | Semo, Inc. | | Oil & Gas Operator | Feb 2002 |
| 441 | Shelf Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 442 | Shoreline Exploration Of Texas | | Oil & Gas Operator | Oct 2000 |
| 443 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 444 | Sierra Production Company | | Oil & Gas Operator | May 1986 |
| 445 | Signal Petroleum | | Oil & Gas Operator | Jul 1980 |
| 446 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2025 |
| 447 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 448 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 449 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 450 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 451 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 452 | Sohio Petroleum Co. Et Al | | Oil & Gas Operator | May 1979 |
| 453 | Sola Oil Company, Inc. | | Oil & Gas Operator | Aug 1991 |
| 454 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 455 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Mar 2025 |
| 456 | South Leeville, LLC | Houston, TX 77069 | Oil & Gas Operator | Oct 2022 |
| 457 | South Oak Production Company | | Oil & Gas Operator | Jun 2010 |
| 458 | South River Operating, LLC | | Oil & Gas Operator | Dec 2016 |
| 459 | Southampton Mineral Corp. | | Oil & Gas Operator | Aug 2005 |
| 460 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 461 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 462 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 463 | Spooner Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 464 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 465 | St. Mary Energy Company | Houston, TX 77079 | Oil & Gas Operator | Aug 2008 |
| 466 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 467 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 468 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 469 | Stone Oil-Quasar-Birthright | | Oil & Gas Operator | Feb 1981 |
| 470 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 471 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Mar 2025 |
| 472 | Sulphur River Exploration, Inc. | Dallas, TX 75244 | Oil & Gas Operator | Mar 2025 |
| 473 | Summit Oil & Gas LLC | | Oil & Gas Operator | Jan 2025 |
| 474 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 475 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 476 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 477 | Superior-American Quasar | | Oil & Gas Operator | Jan 1981 |
| 478 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 479 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |
| 480 | T. N. T. Inc. | | Oil & Gas Operator | Jan 1987 |
| 481 | Tabco Exploration Inc. | New Orleans, LA 70131 | Oil & Gas Operator | Dec 1998 |
| 482 | Talos Energy Offshore LLC | | Oil & Gas Operator | Jan 2025 |
| 483 | Talos Third Coast LLC | | Oil & Gas Operator | Dec 2024 |
| 484 | Tana Exploration Company LLC | Dallas, TX 75219 | Oil & Gas Operator | Aug 2021 |
| 485 | Tchefuncte Natural Resources, L.L.C. | | Oil & Gas Operator | Aug 2011 |
| 486 | Tecpetrol Operating LLC | Houston, TX 77027 | Oil & Gas Operator | Dec 2015 |
| 487 | Telico Minerals, L.L.C. | | Oil & Gas Operator | Oct 2019 |
| 488 | Tellus Operating Group, LLC | | Oil & Gas Operator | Dec 2024 |
| 489 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2024 |
| 490 | Tennessee Gas Pipeline Company | Houston, TX 77252 | Oil & Gas Operator | Dec 2011 |
| 491 | Tennessee Gas Pipeline Company, LLC | Houston, TX 77252 | Oil Operator | Dec 2024 |
| 492 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 493 | Tesoro Petroleum Corporation | | Oil & Gas Operator | May 1982 |
| 494 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Mar 2025 |
| 495 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 496 | Texas Crude & Dale Gas Expl | | Oil & Gas Operator | Dec 1984 |
| 497 | Texas Crude Operator, Inc. | Houston, TX 77098 | Oil & Gas Operator | Aug 2017 |
| 498 | Texas Crude, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 1995 |
| 499 | Texas Crude-Rebstock & Reeves | | Oil & Gas Operator | Feb 1980 |
| 500 | Texas Eastern Transm. Corp. | | Oil & Gas Operator | Dec 2002 |