| 501 | Shale Energy LLC | Jeffersonville, KY 40337 | Oil Operator | Dec 2018 |
| 502 | Shenandoah Petroleum Corporation | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 503 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Jul 2026 |
| 504 | Shirley, B. J. | Lawn, TX 79530 | Oil & Gas Operator | Mar 2008 |
| 505 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Jul 2026 |
| 506 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 507 | Smith & Marrs Inc. | Lubbock, TX 79424 | Oil & Gas Operator | Apr 2021 |
| 508 | Smith Brothers Oil & Gas, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 509 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 510 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Jul 2026 |
| 511 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 512 | Socorro Exploration, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Jul 2026 |
| 513 | Sogc, Inc. | Salt Lake Cty, UT 84131 | Oil & Gas Operator | May 2026 |
| 514 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 515 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 516 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 517 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Jul 2026 |
| 518 | Spur Energy | Midland, TX 79708 | Oil & Gas Operator | Mar 1996 |
| 519 | Staley Operating Co. | Midland, TX 79702 | Oil & Gas Operator | Jan 2022 |
| 520 | Stallion Energy, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2017 |
| 521 | Statoil Oil & Gas LP | Austin, TX 78730 | Oil & Gas Operator | Oct 2018 |
| 522 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 523 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 524 | Stickney, F. C., Inc. | Midland, TX 79704 | Oil & Gas Operator | Oct 1998 |
| 525 | Strata Petroleum Co. | Midland, TX 79701 | Oil & Gas Operator | May 1997 |
| 526 | Stratco Operating Co., Inc. | Austin, TX 78701 | Oil & Gas Operator | Jul 2026 |
| 527 | Stringer Oil & Gas Co., Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Oct 1996 |
| 528 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 529 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Jul 2026 |
| 530 | Swab Oil Co. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 531 | Swanson Operating, Inc. | Holliday, TX 76366 | Oil Operator | Jul 2026 |
| 532 | Swanson, Tom | Electra, TX 76360 | Oil & Gas Operator | Oct 2004 |
| 533 | Synergex Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2026 |
| 534 | T.O.I. | Midland, TX 79710 | Oil & Gas Operator | Mar 2001 |
| 535 | Tacor Resources Inc | Midland, TX 79705 | Oil & Gas Operator | Jul 2026 |
| 536 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 2026 |
| 537 | Tara Operating Co. | Lamesa, TX 79331 | Oil & Gas Operator | Aug 2003 |
| 538 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 539 | Targa Pipeline Mid-Continent LLC | Sulphur, LA 70665 | Oil & Gas Operator | Jun 2018 |
| 540 | Taurus Exploration U.S.A., Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 1998 |
| 541 | Taurus Operating, Inc. | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 542 | TB Petroleum, LLC | Petrolia, TX 76377 | Oil & Gas Operator | Jul 2026 |
| 543 | Teco Oil & Gas, Inc. | Tampa, FL 33601 | Oil & Gas Operator | Nov 1997 |
| 544 | Tejas Operators, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 2003 |
| 545 | Tejas Permian Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 546 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jul 2026 |
| 547 | Terrace Petroleum Corporation | Midland, TX 79701 | Oil & Gas Operator | Jul 2013 |
| 548 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Jul 2026 |
| 549 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 550 | Texas Crude Operator, Inc. | Houston, TX 77098 | Oil & Gas Operator | Aug 2017 |
| 551 | Texas Mineral Group | Midland, TX 79705 | Oil & Gas Operator | Aug 2013 |
| 552 | Texas Vanguard Oil Company | Austin, TX 78720 | Oil & Gas Operator | Jan 2014 |
| 553 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 554 | Three Rivers Operating Co II LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 555 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 556 | Tiburon Oil & Gas, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2000 |
| 557 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 558 | Tola Production Company | Dallas, TX 75367 | Oil & Gas Operator | Jul 2026 |
| 559 | Trail Ridge Energy PRTNS II LLC | Grapevine, TX 76051 | Oil & Gas Operator | Jun 2017 |
| 560 | Trek Aec, LLC | Wichita, KS 67202 | Oil & Gas Operator | Mar 2026 |
| 561 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Jul 2026 |
| 562 | Triag Energy Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2014 |
| 563 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | Jul 2026 |
| 564 | Trinity Operating & Prod., Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 565 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 566 | Tripower Resources LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jul 2026 |
| 567 | Triumph Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 568 | Trivista Operating LLC | Giddings, TX 78942 | Oil & Gas Operator | Jul 2026 |
| 569 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 570 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 571 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Jul 2026 |
| 572 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 573 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 574 | Valla Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Aug 2003 |
| 575 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 576 | Vanguard Permian, LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 577 | Vector Oil & Gas LP | Midland, TX 79701 | Oil & Gas Operator | Sep 2014 |
| 578 | Vencer Energy, LLC | Abilene, TX 79602 | Oil & Gas Operator | Dec 2023 |
| 579 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Apr 2026 |
| 580 | Veritas Energy LLC | San Antonio, TX 78231 | Oil & Gas Operator | Jul 2026 |
| 581 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 582 | Vintage Petroleum, LLC | Houston, TX 77210 | Oil & Gas Operator | Dec 2019 |
| 583 | Vista Resources, Inc. (A) | Midland, TX 79701 | Oil & Gas Operator | Feb 2000 |
| 584 | W&T Offshore, Inc. | Houston, TX 77057 | Oil & Gas Operator | Jul 2026 |
| 585 | W.A. Oil Co. | Andrews, TX 79714 | Oil & Gas Operator | Aug 1997 |
| 586 | W.H.D., Inc. | Euless, TX 76039 | Oil & Gas Operator | Aug 1998 |
| 587 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2026 |
| 588 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 589 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Jul 2026 |
| 590 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 591 | Warrior Exploration LLC | Sapulpa, OK 74067-1912 | Oil & Gas Operator | Mar 2026 |
| 592 | Wash, Robert C. Inc. | Forsan, TX 79733 | Oil & Gas Operator | Jul 2026 |
| 593 | Watusi Energy LLC | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 594 | West Texas Oil And Gas Corp. | Houston, TX 77056 | Oil & Gas Operator | Feb 2014 |
| 595 | West Texas Oil And Gas Oper.,Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2024 |
| 596 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 597 | White Wing Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2012 |
| 598 | White, Ralph H. | Midland, TX 79701 | Oil & Gas Operator | Oct 2002 |
| 599 | Whitfield Energy | Midland, TX 79702 | Oil & Gas Operator | Jan 1999 |
| 600 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Jul 2026 |