| 501 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Sep 2026 |
| 502 | Sagebrush Operating LLC | Denver, CO 80203 | Oil & Gas Operator | Mar 2026 |
| 503 | Salt Creek Production, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Sep 2026 |
| 504 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 505 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 506 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2026 |
| 507 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2026 |
| 508 | Samurai Operating Co. L.L.C. | Dayton, TX 77535 | Oil & Gas Operator | Sep 2026 |
| 509 | San Cajo Oil Company | Edmonds, WA 98020 | Oil & Gas Operator | Sep 2026 |
| 510 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 511 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Sep 2026 |
| 512 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 513 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 514 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Sep 2026 |
| 515 | Sandia Operating Corp. | San Antonio, TX 78270 | Oil & Gas Operator | May 2010 |
| 516 | Sandridge Onshore, LLC | Houston, TX 77010 | Oil & Gas Operator | Jun 2014 |
| 517 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |
| 518 | Saxum Oil & Gas, LLC | Beeville, TX 78104 | Oil & Gas Operator | Sep 2026 |
| 519 | Se USA Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 520 | Sea Eagle Ford, LLC | Denver, CO 80265 | Oil & Gas Operator | Jun 2022 |
| 521 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 522 | Secondary Oil Corp., Inc. | Austin, TX 78750 | Oil Operator | Apr 1999 |
| 523 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 524 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 525 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2026 |
| 526 | Sierra Exploration Company | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2008 |
| 527 | Sierra Resources, LLC | Houston, TX 77219 | Oil & Gas Operator | Aug 2021 |
| 528 | Silver Hill Energy Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Sep 2026 |
| 529 | Silverbow Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2026 |
| 530 | Simray GP, LLC | Richardson, TX 75080 | Oil & Gas Operator | Dec 2015 |
| 531 | Simray Oil & Gas, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Sep 2003 |
| 532 | Simray Operating Corp. | Richardson, TX 75080 | Oil & Gas Operator | Mar 2009 |
| 533 | Skidmore Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Jul 1997 |
| 534 | SM Operating Company LLC | Austin, TX 78709 | Oil & Gas Operator | Sep 2026 |
| 535 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 536 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Sep 2026 |
| 537 | South Texas Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2026 |
| 538 | South Texas SWD, Inc. | Beeville, TX 78104 | Oil & Gas Operator | Aug 2003 |
| 539 | Southern Resource Company | Corpus Christ, TX 78404 | Oil & Gas Operator | Mar 2022 |
| 540 | Southern Royalty Inc. | Corpus Christ, TX 78411 | Oil & Gas Operator | Feb 1997 |
| 541 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 542 | Southwest Gathering Company | Alice, TX 78332 | Oil & Gas Operator | Sep 2026 |
| 543 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 544 | Southwest Oil & Land, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 1999 |
| 545 | Stallion Oil Company | Lafayette, LA 70505 | Oil & Gas Operator | Jun 2004 |
| 546 | Staples, James W. Prod. Co. | Tuleta, TX 78162 | Oil & Gas Operator | Sep 2026 |
| 547 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 548 | Starco Exploration, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Sep 2026 |
| 549 | Statoil Texas Onshore Prop LLC | Austin, TX 78730 | Oil & Gas Operator | Dec 2018 |
| 550 | Sterling Engine Service, Inc. | Alice, TX 78333 | Oil & Gas Operator | Sep 2026 |
| 551 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Sep 2026 |
| 552 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Sep 2026 |
| 553 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 554 | Suemaur Expl. & Prod., LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Jun 2024 |
| 555 | Suemaur Exploration, Inc. | Corpus Chrsti, TX 78470 | Oil & Gas Operator | Mar 2008 |
| 556 | Sun Exploration, Inc. | Alice, TX 78333 | Oil & Gas Operator | Sep 2026 |
| 557 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Sep 2026 |
| 558 | Sure Flow Oil & Gas, Inc. | Victoria, TX 77902 | Oil & Gas Operator | Sep 2026 |
| 559 | Sutton Producing Corp. | San Antonio, TX 78270 | Oil & Gas Operator | Sep 2026 |
| 560 | SV Energy Company, LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Mar 2017 |
| 561 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 562 | Syj Oil & Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2026 |
| 563 | Synergy Oil & Gas, Inc. (A) | Houston, TX 77024 | Oil & Gas Operator | Aug 2001 |
| 564 | Talbott, Stan C. | Midland, TX 79701 | Oil & Gas Operator | Feb 2005 |
| 565 | Talisman Energy USA Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2016 |
| 566 | Tallgrass Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2026 |
| 567 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 568 | Tanos Production, Inc. | Houston, TX 77077 | Oil & Gas Operator | Aug 2003 |
| 569 | Tare Resources, LLC | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Sep 2026 |
| 570 | Targa Midstream Services LLC | Tulsa, OK 74103 | Oil Operator | Mar 2023 |
| 571 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Sep 2026 |
| 572 | Teal Operating, LLC | Dallas, TX 75225 | Oil & Gas Operator | Oct 2021 |
| 573 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2026 |
| 574 | Terrafina Energy, LLC | San Antonio, TX 78280 | Oil & Gas Operator | Sep 2026 |
| 575 | Tesoro E&P Company, L.P. | San Antonio, TX 78216 | Oil & Gas Operator | Jan 2000 |
| 576 | Teton Petroleum Corporation | Kerrville, TX 78028 | Oil & Gas Operator | Sep 2026 |
| 577 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Sep 2026 |
| 578 | Texas Crude, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 1995 |
| 579 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | Sep 2026 |
| 580 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 581 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 582 | Texas Land & Petro Co., LLC | Carrollton, TX 75010 | Oil & Gas Operator | Sep 2026 |
| 583 | Texas Secondary Oil Corporation | Devine, TX 78016 | Oil & Gas Operator | Sep 2026 |
| 584 | Texas Southern Petroleum Corp. | Corpus Christ, TX 78410 | Oil & Gas Operator | Sep 2026 |
| 585 | Texas Western Energy Corporation | Portland, TX 78374 | Oil & Gas Operator | Nov 2002 |
| 586 | Texas, Les & Co. | Brenham, TX 77833 | Oil & Gas Operator | Sep 2026 |
| 587 | Texoil Ventures LLC | The Woodlands, TX 77382 | Oil Operator | Sep 2026 |
| 588 | Thomas Oil & Gas Company | Luling, TX 78648 | Oil & Gas Operator | Aug 2003 |
| 589 | Three C Exploration, LLC | Hebbronville, TX 78361 | Oil & Gas Operator | Sep 2026 |
| 590 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jul 2026 |
| 591 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Sep 2026 |
| 592 | Tidewater Minerals Corporation | Orange Grove, TX 78372 | Oil & Gas Operator | Sep 2026 |
| 593 | Torch Energy Services, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 594 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 595 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 596 | Trailblazer Oil & Gas LLC | Goliad, TX 77963 | Oil & Gas Operator | Sep 2026 |
| 597 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 598 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Sep 2026 |
| 599 | Trident Corporation | Woodsboro, TX 78393 | Oil & Gas Operator | Sep 2026 |
| 600 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |