| 501 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 502 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 503 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2026 |
| 504 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | May 2026 |
| 505 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Sep 2026 |
| 506 | Sbog, LLC | Granbury, TX 76048 | Oil & Gas Operator | Feb 2021 |
| 507 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 508 | Scheriger Production | Graham, TX 76450 | Oil & Gas Operator | Jun 2006 |
| 509 | Scroggins, Bruce E. | Gilmer, TX 75645 | Oil & Gas Operator | Aug 2004 |
| 510 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 511 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Sep 2026 |
| 512 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 513 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 514 | Shappell Oil Company, L.L.C. | Harrisonburg, LA 71340 | Oil & Gas Operator | Sep 2026 |
| 515 | Shelby Operating Company | Dallas, TX 75205 | Oil & Gas Operator | Sep 2026 |
| 516 | Shelby, Michael H. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2026 |
| 517 | Sheridan Production Co III, LLC | Houston, TX 77056 | Oil & Gas Operator | Sep 2026 |
| 518 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | May 2026 |
| 519 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Sep 2026 |
| 520 | Shivers, Linward, Operator | Shreveport, LA 71161 | Oil & Gas Operator | Sep 1997 |
| 521 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 522 | Shoshone Oil Company | Dallas, TX 75244 | Oil & Gas Operator | May 1994 |
| 523 | SHWJ Oil & Gas Co., Inc. | Oil City, LA 71061 | Oil Operator | Sep 2026 |
| 524 | Sikes Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2003 |
| 525 | Silver Hill Energy Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | Sep 2026 |
| 526 | Silver Oak Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 2009 |
| 527 | Silver Oak Operating, LLC | Longview, TX 75604 | Oil & Gas Operator | Sep 2026 |
| 528 | Sinclair Development, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 529 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2026 |
| 530 | Slant Operating, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Sep 2026 |
| 531 | SM Operating Company LLC | Austin, TX 78709 | Oil & Gas Operator | Sep 2026 |
| 532 | Smal Energy Corp | Tyler, TX 75710 | Oil & Gas Operator | Oct 1995 |
| 533 | Smith Operating & Management Co. | Shreveport, LA 71161 | Oil & Gas Operator | Feb 2005 |
| 534 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 535 | Smith Resources, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2026 |
| 536 | Smith Resources, L.L.C. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2026 |
| 537 | Smith, E.N. III Energy Corp. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2006 |
| 538 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | May 2026 |
| 539 | Sogc, Inc. | Salt Lake Cty, UT 84131 | Oil & Gas Operator | Jun 2026 |
| 540 | Sojitz Energy Venture, Inc. | Houston, TX 77042 | Oil & Gas Operator | Feb 2018 |
| 541 | Soldier Creek Energy, LLC | Edmond, OK 73013 | Oil & Gas Operator | Sep 2026 |
| 542 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 543 | Sonat Exploration Company -Tyler | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 544 | Sonat Exploration Company-MCR | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 545 | Sonora Petroleum Corp. | Austin, TX 78734 | Oil & Gas Operator | Sep 2026 |
| 546 | Southerland, Glenn Oil & Gas Co. | Hallsville, TX 75650 | Oil & Gas Operator | Feb 2021 |
| 547 | Southern Crude, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2017 |
| 548 | Southwest Energy LP | Tulsa, OK 74136 | Oil & Gas Operator | May 2026 |
| 549 | Southwest Operating, Inc.-Tyler | Tyler, TX 75701 | Oil & Gas Operator | Sep 2026 |
| 550 | Spartan Operating Company, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Feb 2013 |
| 551 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Sep 2026 |
| 552 | Sponte Operating, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Sep 2026 |
| 553 | Stroube Energy Corporation | Dallas, TX 75248 | Oil & Gas Operator | Jan 2012 |
| 554 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | Sep 2026 |
| 555 | Stuart Oil & Gas | Longview, TX 75606 | Oil & Gas Operator | Sep 2026 |
| 556 | Sunland Production Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | May 2026 |
| 557 | Superior Royalty, LLC | Lindale, TX 75771 | Oil Operator | Sep 2026 |
| 558 | Sydri Operating, LLC | Dallas, TX 75231 | Oil & Gas Operator | Sep 2026 |
| 559 | T W Clemons Operating Co., LLC | Minden, LA 71055 | Oil & Gas Operator | Sep 2026 |
| 560 | T. And M. Production | Oil City, LA 71061 | Oil & Gas Operator | Sep 2026 |
| 561 | T.O.I. | Midland, TX 79710 | Oil & Gas Operator | Mar 2001 |
| 562 | Tag Team Resources LLC | Eufaula, OK 74432 | Oil & Gas Operator | May 2026 |
| 563 | Tanos Exploration II, LLC | Tyler, TX 75701 | Oil & Gas Operator | Sep 2023 |
| 564 | Tanos Exploration IV, LLC | Tyler, TX 75703 | Oil & Gas Operator | Sep 2026 |
| 565 | Tanos Exploration, LLC | Houston, TX 77010 | Oil & Gas Operator | Oct 2018 |
| 566 | TC Energy LLC | Covington, OK 73730-2116 | Oil & Gas Operator | Sep 2014 |
| 567 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Sep 2026 |
| 568 | TC3 Energy Company | Dallas, TX 75248 | Oil & Gas Operator | Sep 2026 |
| 569 | Tenison Oil Company | Abilene, TX 79605 | Oil & Gas Operator | May 2026 |
| 570 | Terry Petroleum Company | Houston, TX 77270 | Oil & Gas Operator | Dec 1997 |
| 571 | Tesoro E&P Company, L.P. | San Antonio, TX 78216 | Oil & Gas Operator | Jan 2000 |
| 572 | Tex-Ok Energy, LTD Partnership | Cody, WY 82414 | Oil & Gas Operator | Sep 2026 |
| 573 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Sep 2026 |
| 574 | Texas Royalty Corp. | Austin, TX 78746 | Oil & Gas Operator | Sep 2026 |
| 575 | Texla Operating Co | Jonesville, TX 75659 | Oil & Gas Operator | Sep 2026 |
| 576 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 577 | Texlan Oil Company, L.C. | Tyler, TX 75711 | Oil & Gas Operator | Aug 2003 |
| 578 | TGNR East Texas II LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 579 | TGNR East Texas LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 580 | TGNR Gulf Coast LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 581 | TGNR TVL LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 582 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Jul 2026 |
| 583 | Thor-Max Operating, Inc. | Plano, TX 75025 | Oil & Gas Operator | Sep 2026 |
| 584 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jun 2026 |
| 585 | Thunderbird (Texas) Resources LP | Edmond, OK 73025 | Oil & Gas Operator | Apr 2019 |
| 586 | Tipco Operating Co. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2026 |
| 587 | Titan Rock E&P, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2024 |
| 588 | Torch Energy Services, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 589 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 590 | Tri-State Exploration & Prod Inc | Marshall, TX 75671 | Oil & Gas Operator | Aug 2003 |
| 591 | Trich Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2025 |
| 592 | Trico Oil & Gas Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Sep 2026 |
| 593 | Trinity Operating (Usg), LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 594 | Triple J Investments Inc | Longview, TX 75606 | Oil & Gas Operator | Feb 2023 |
| 595 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 596 | Trivium Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Sep 2026 |
| 597 | Tyler Oil & Gas Inc. | Tyler, TX 75702 | Oil & Gas Operator | Sep 2004 |
| 598 | U. S. Energy Development Corporation | Fort Worth, TX 76164 | Oil & Gas Operator | Sep 2026 |
| 599 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 600 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |