| 401 | Pmo | Garland, TX 75040 | Oil & Gas Operator | Feb 2018 |
| 402 | Pogo Producing Company | Houston, TX 77002 | Oil & Gas Operator | Jan 2008 |
| 403 | Ponderosa Oil & Gas, LLC | Houston, TX 77008 | Oil & Gas Operator | Dec 2025 |
| 404 | Powerline Energy Corporation | Arlington, TX 76015 | Oil & Gas Operator | Dec 2025 |
| 405 | Presidio Exploration, Inc. | Englewood, CO 80155 | Oil & Gas Operator | May 1999 |
| 406 | Pride Energy Company | Tulsa, OK 74170 | Oil & Gas Operator | Dec 2025 |
| 407 | Prime Natural Resources, Inc. | Houston, TX 77042 | Oil & Gas Operator | Jun 2007 |
| 408 | Prime Operating Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 409 | Prize Operating Company | Grapevine, TX 76051 | Oil & Gas Operator | Aug 2016 |
| 410 | Production Gathering Company, LP | Dallas, TX 75206 | Oil & Gas Operator | Dec 2025 |
| 411 | Proex Energy Management, L.L.C. | Spring, TX 77386 | Oil & Gas Operator | Dec 2025 |
| 412 | Progenies Operating LLC | Austin, TX 78746 | Oil & Gas Operator | Dec 2025 |
| 413 | Proline Energy Resources Inc | Sugar Land, TX 77479 | Oil & Gas Operator | Dec 2025 |
| 414 | Puls, W. L. | Houston, TX 77084 | Oil & Gas Operator | Sep 2002 |
| 415 | Pyramid Exploration | Houston, TX 77241 | Oil & Gas Operator | Sep 1995 |
| 416 | Quantum Resources Management LLC | Houston, TX 77010 | Oil & Gas Operator | Oct 2025 |
| 417 | Quintana Pet. Corp. | Refugio, TX 78377 | Oil & Gas Operator | Dec 2000 |
| 418 | Radius Operating, LLC | Round Rock, TX 78664 | Oil & Gas Operator | Dec 2025 |
| 419 | Rainbow Resources, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Aug 2007 |
| 420 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 421 | Ranger Oil Company | Canada, 00100 | Oil & Gas Operator | Sep 2001 |
| 422 | Reliant Exploration, LTD. | Houston, TX 77060 | Oil & Gas Operator | Sep 2002 |
| 423 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Dec 2025 |
| 424 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 425 | Rio Petroleum, Inc. | Amarillo, TX 79102 | Oil & Gas Operator | Dec 2025 |
| 426 | Rocinante | Houston, TX 77058 | Oil Operator | Dec 2025 |
| 427 | Rockbridge Oil And Gas, Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1997 |
| 428 | Rockoil Energy Of Texas, Inc. | Weatherford, TX 76086 | Oil & Gas Operator | Dec 2025 |
| 429 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | Dec 2025 |
| 430 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Dec 2025 |
| 431 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 432 | Royal Texas Petroleum | Lago VIsta, TX 78645 | Oil & Gas Operator | Dec 2025 |
| 433 | Rse, Inc. | Houston, TX 77077 | Oil & Gas Operator | Sep 2000 |
| 434 | Rust Oil Corp. | Fort Worth, TX 76121 | Oil & Gas Operator | Dec 2025 |
| 435 | Rutherford Oil Corporation | Houston, TX 77046 | Oil & Gas Operator | Jun 2019 |
| 436 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Dec 2025 |
| 437 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 438 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 439 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 440 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2025 |
| 441 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 442 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | Dec 2025 |
| 443 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 444 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Dec 2025 |
| 445 | Sandpoint Texas LLC | Houston, TX 77270 | Oil Operator | Dec 2025 |
| 446 | Sanhall Corporation | Huntsville, TX 77340 | Oil & Gas Operator | Oct 1993 |
| 447 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |
| 448 | Sawtooth Operating Co., Inc. | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 449 | Sawtooth, Inc. | Houston, TX 77024 | Oil & Gas Operator | Dec 2013 |
| 450 | Scoggins Oil & Gas Co. | Seabrook, TX 77586 | Oil & Gas Operator | Jun 2000 |
| 451 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Dec 2025 |
| 452 | Seashore Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 453 | Seneca Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 454 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 455 | Setex Oil Company, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jan 2000 |
| 456 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 457 | Shepperd, William M. | Houston, TX 77279 | Oil & Gas Operator | Sep 2012 |
| 458 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 459 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Dec 2025 |
| 460 | Shubuta Oil Corporation | Houston, TX 77056 | Oil & Gas Operator | Sep 1998 |
| 461 | Shuler Drilling Co., Inc. | El Dorado, AR 71730 | Oil & Gas Operator | Jan 2025 |
| 462 | Sideline Oil & Gas, L.P. | Friendswood, TX 77549 | Oil Operator | Dec 2025 |
| 463 | Silver Oak Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 2009 |
| 464 | Silver Oak Operating, LLC | Longview, TX 75604 | Oil & Gas Operator | Dec 2025 |
| 465 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Sep 2025 |
| 466 | Skyway Energy LLC | Leesburg, OH 34748 | Oil & Gas Operator | Dec 2020 |
| 467 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 468 | Smith Oil Co. | Smackover, AR 71762 | Oil Operator | Jan 2025 |
| 469 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Dec 2025 |
| 470 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Dec 2025 |
| 471 | Sonterra Oil & Gas, Inc. | Wichita, KS 67217 | Oil & Gas Operator | Dec 2025 |
| 472 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Dec 2025 |
| 473 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 474 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Dec 2025 |
| 475 | Standard Resources Corp. | Houston, TX 77063 | Oil & Gas Operator | Dec 2025 |
| 476 | Statoil Oil & Gas LP | Austin, TX 78730 | Oil & Gas Operator | Oct 2018 |
| 477 | Stealth Onsite Solutions LLC | Pasadena, TX 77505 | Oil Operator | Dec 2025 |
| 478 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Oct 2025 |
| 479 | Stone Mountain Petroleum, LLC | Houston, TX 77008 | Oil & Gas Operator | Aug 2002 |
| 480 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Dec 2025 |
| 481 | Stroud Production LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 482 | STS Petroleum LLC | Houston, TX 77289 | Oil & Gas Operator | Dec 2025 |
| 483 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Dec 2025 |
| 484 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 485 | Suemaur Expl. & Prod., LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jun 2024 |
| 486 | Sunray Operating Company LLC | Sugar Land, TX 77498 | Oil & Gas Operator | Nov 2024 |
| 487 | Sunset Energy L L C | Palm Harbor, FL 34683-3044 | Oil Operator | Dec 2007 |
| 488 | T & J Oil Production, L.L.C. | Lone Grove, OK 73443 | Oil & Gas Operator | Oct 2025 |
| 489 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | Dec 2025 |
| 490 | Tap Operating Company, Inc. | Mexia, TX 76667 | Oil & Gas Operator | May 1995 |
| 491 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Dec 2025 |
| 492 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 493 | Templeton Oil, Inc. | Houston, TX 77002 | Oil & Gas Operator | Nov 1994 |
| 494 | Tenexco Inc | Oakbrook Terrace, IL 60181 | Gas Operator | Dec 1998 |
| 495 | Tepco Resources, Inc. | Houston, TX 77027 | Oil & Gas Operator | Sep 2004 |
| 496 | Tepco, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 1999 |
| 497 | Terry Enterprises, Inc. | West Columbia, TX 77486 | Oil & Gas Operator | Dec 2025 |
| 498 | Terry, R. K. | West Columbia, TX 77486 | Oil & Gas Operator | Dec 2025 |
| 499 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Dec 2025 |
| 500 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | Dec 2025 |