| 501 | S. P. Penntex Energy, L.P. | Abilene, TX 79605 | Oil & Gas Operator | May 2003 |
| 502 | S.B. Street Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 503 | Sabre Oil And Gas Corp. | Houston, TX 77063 | Oil & Gas Operator | Feb 2026 |
| 504 | Sabre Operating, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 505 | Sage Natural Resources LLC | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 506 | Sage Oil And Gas, LLC | Graham, TX 76450 | Gas Operator | Feb 2026 |
| 507 | Saguaro Petroleum, LLC | Midland, TX 79705 | Oil & Gas Operator | Feb 2026 |
| 508 | Salt Of The Earth Energy, LLC | Montgomery, TX 77356 | Oil & Gas Operator | Feb 2026 |
| 509 | Sanco Operating Company | Bullard, TX 75757 | Oil & Gas Operator | Feb 2026 |
| 510 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 511 | Sandollar Oil & Gas, Inc. | Hallsville, TX 75650 | Oil & Gas Operator | Feb 1993 |
| 512 | Scully And Smith Oil Corporation | Salado, TX 76571 | Oil & Gas Operator | Feb 1995 |
| 513 | Seely Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 514 | Sendero Energy Inc. | Dallas, TX 75205 | Oil & Gas Operator | Feb 2026 |
| 515 | Sequoia Energy Resources | Dallas, TX 75207 | Oil & Gas Operator | Feb 2026 |
| 516 | Sequoia Fossil Fuels, Inc. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 517 | Sequoia Natural Gas, Inc. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 518 | Serendipity Exploration, Inc. | Weatherford, TX 76087 | Gas Operator | May 1997 |
| 519 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 520 | Sha Stephens, Incorporated | Weatherford, TX 76087 | Oil & Gas Operator | Apr 2006 |
| 521 | Shaida, John H. | Wichita, KS 67226 | Oil & Gas Operator | Feb 2026 |
| 522 | Sharoco Corporation | Fort Worth, TX 76121 | Oil & Gas Operator | Dec 1996 |
| 523 | Shell Western E&P | Houston, TX 77001 | Oil & Gas Operator | Feb 2026 |
| 524 | Shelley, Richard W | Wichita Falls, TX 76310 | Oil & Gas Operator | Jun 2015 |
| 525 | Silver Creek Oil & Gas, LLC | Flower Mound, TX 75022 | Oil & Gas Operator | Feb 2026 |
| 526 | Silver Creek Resources, LLC | Irving, TX 75038 | Oil & Gas Operator | Apr 2017 |
| 527 | Simpson Oil & Land Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 528 | Sitton, Ronnie Incorporated | Graford, TX 76449 | Oil & Gas Operator | Feb 2020 |
| 529 | Sky Development Corporation | Graham, TX 76450 | Oil & Gas Operator | Mar 2008 |
| 530 | Sky Resources, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 531 | Skybridge Energy LLC | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 532 | Slate Holdings, Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 533 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 534 | Smith, J.V. Oil Company | Dallas, TX 75248 | Gas Operator | Jul 2025 |
| 535 | Snow Operating Co., Inc. | Haltom City, TX 76117 | Oil & Gas Operator | Feb 2024 |
| 536 | Spartagus Corporation | Grand Saline, TX 75140 | Oil & Gas Operator | Sep 2004 |
| 537 | Spence Energy Company | Dallas, TX 75360 | Oil & Gas Operator | Feb 2026 |
| 538 | Spi Operations LLC | Midland, TX 79710 | Oil & Gas Operator | Jan 2013 |
| 539 | Spindletop Drilling Co. | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 540 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 541 | SRG Oil Corporation | Abilene, TX 79604 | Oil & Gas Operator | Apr 1994 |
| 542 | St Johns Operating #1 LP | Houston, TX 77060 | Oil & Gas Operator | Aug 2023 |
| 543 | Staley Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Jan 2000 |
| 544 | Stamper Operating Co., Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 545 | Star Operating, Inc | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2026 |
| 546 | STB Energy Inc. | Tulsa, OK 74105 | Oil & Gas Operator | Jul 2008 |
| 547 | Steller Energy & Investment Corp | Plano, TX 75093 | Oil & Gas Operator | Feb 2021 |
| 548 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 549 | Stephens Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Feb 2022 |
| 550 | Stephens, Clayton E. | Dallas, TX 75229 | Oil & Gas Operator | Nov 2011 |
| 551 | Stephens, Hayseed Oil Inc. | Weatherford, TX 76087 | Oil & Gas Operator | Mar 2008 |
| 552 | Stephens, Morris | Graham, TX 76450 | Oil & Gas Operator | May 1996 |
| 553 | Sterling Oil And Gas | Weatherford, TX 76086 | Oil & Gas Operator | Feb 2026 |
| 554 | Stewart & Porter | Mingus, TX 76463 | Oil & Gas Operator | Apr 2002 |
| 555 | Stivers Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 1995 |
| 556 | Stober Oil And Gas Services, LLC | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2026 |
| 557 | Stone Creek Operating, LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Feb 2026 |
| 558 | Stonebriar Oil LLC | Frisco, TX 75034 | Oil & Gas Operator | Feb 2026 |
| 559 | Stovall Operating Co. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 560 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 561 | Street, Spencer B., Jr. | Graham, TX 76450 | Oil & Gas Operator | Mar 1998 |
| 562 | Sun-Key Oil Co., Inc. | Dublin, TX 76446 | Oil & Gas Operator | Feb 2026 |
| 563 | Sunrise Oil, LTD. | Wichita Falls, TX 76307 | Oil & Gas Operator | Aug 2004 |
| 564 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Feb 2026 |
| 565 | Swan PC, LP | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 566 | Swan Production Co. | Jacksboro, TX 76458 | Oil & Gas Operator | Nov 2009 |
| 567 | Swartz Oil Company | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2026 |
| 568 | Sweetwater Drilling Co., Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Feb 2026 |
| 569 | T & S Oil & Gas, LLC | Graham, TX 76450 | Gas Operator | Feb 2026 |
| 570 | Talon Production, Inc. | Wichita Falls, TX 76301 | Oil & Gas Operator | Feb 2026 |
| 571 | Talus Inc | Graham, TX 76450-1210 | Oil & Gas Operator | Feb 2017 |
| 572 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 573 | Tandem Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 574 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 575 | Targo Oil & Gas, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 576 | Tarpon Oil & Gas Co. | Fort Worth, TX 76147 | Oil & Gas Operator | Feb 2026 |
| 577 | Tarpon Oil Company | Fort Worth, TX 76107 | Oil & Gas Operator | Jun 2016 |
| 578 | Taubert & Steed | Wichita Falls, TX 76301 | Oil & Gas Operator | Aug 2001 |
| 579 | Taylor, Ben J. Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2022 |
| 580 | Taylor, G. E. | Bridgeport, TX 76426 | Oil & Gas Operator | Jan 2001 |
| 581 | Taylor, J. S. Inc. | Lewisville, TX 75057 | Oil & Gas Operator | Feb 2026 |
| 582 | Tejas Western Corp. | Granbury, TX 76048 | Oil & Gas Operator | Jul 2018 |
| 583 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Feb 2026 |
| 584 | Tempo Resources GP, LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Apr 2013 |
| 585 | Tessara Petroleum Resources, LLC | Houston, TX 77086 | Oil & Gas Operator | Apr 2020 |
| 586 | Tex-Am Petroleum Corp. | Eastland, TX 76448 | Oil & Gas Operator | Feb 2026 |
| 587 | Texas Pharchem Inc. | Abilene, TX 79601 | Oil & Gas Operator | Apr 2019 |
| 588 | Texas Shallow Oil & Gas, LLC | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 589 | Texdon Operating | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2005 |
| 590 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 591 | Texu Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Jan 2007 |
| 592 | Texxol Operating Company, Inc. | Fort Worth, TX 76108 | Oil & Gas Operator | Feb 2026 |
| 593 | TFX, Inc. | Graham, TX 76450 | Oil & Gas Operator | Oct 2019 |
| 594 | Thomas, R. W. Inc. | Norman, OK 73070 | Oil & Gas Operator | Apr 2015 |
| 595 | Three B Corporation | Fort Worth, TX 76179 | Gas Operator | Jun 2009 |
| 596 | Three B Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 597 | Three B, LP | Fort Worth, TX 76179 | Gas Operator | Feb 2026 |
| 598 | Three P Operating Co.,GP, L.L.C. | Newcastle, TX 76372 | Oil & Gas Operator | Feb 2026 |
| 599 | Three P Operating Company | Newcastle, TX 76372 | Oil & Gas Operator | Nov 2007 |
| 600 | Threshold Development Company | Fort Worth, TX 76109 | Oil & Gas Operator | Aug 2016 |