| 501 | Robertson Resources, Inc. | Midland, TX 79708 | Oil & Gas Operator | May 2025 |
| 502 | Roca Operating, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 503 | Roden Oil Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2008 |
| 504 | Romine Oil & Gas, LLC | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 505 | Royalty Resources, L.L.C. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 506 | Rust Oil Corp. | Fort Worth, TX 76108 | Oil & Gas Operator | May 2025 |
| 507 | Saba Energy Of Texas Inc | Houston, TX 77042 | Oil & Gas Operator | Jul 2007 |
| 508 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | May 2025 |
| 509 | Sahara Operating Company | Midland, TX 79704 | Oil & Gas Operator | May 2025 |
| 510 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 511 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | May 2025 |
| 512 | Santa Fe Snyder Corporation | Houston, TX 77024 | Oil & Gas Operator | Oct 2000 |
| 513 | Sapient Energy Corp | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2002 |
| 514 | Savannah Ross And Company, LLC | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 515 | SBJ Oil & Gas, LLC | Iraan, TX 79744 | Oil & Gas Operator | May 2025 |
| 516 | Schlachter Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | May 2025 |
| 517 | Schlagal, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2016 |
| 518 | Scout Energy Management LLC | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 519 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 520 | SDG Resources L.P. | Montrose, CO 81402 | Oil & Gas Operator | May 2006 |
| 521 | Sea Sand Oil Company | Fort Worth, TX 76185 | Oil & Gas Operator | Jun 1995 |
| 522 | Sed Energy Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 523 | Seguro Oil And Gas, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2024 |
| 524 | SFM Holdings, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 1995 |
| 525 | Sharp Image Energy, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | May 2025 |
| 526 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 527 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2025 |
| 528 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | May 2025 |
| 529 | Shinnery Oil Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 530 | Siana Oil & Gas | Conroe, TX 77305 | Oil & Gas Operator | May 2025 |
| 531 | Simata Energy, LLC | Midland, TX 79708 | Oil & Gas Operator | May 2025 |
| 532 | Simmons, L.B. Energy, Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 2000 |
| 533 | Simpson Bros. Oil Co. | Odessa, TX 79760 | Oil & Gas Operator | Jan 2001 |
| 534 | Simpson Oil Company | Odessa, TX 79760 | Oil & Gas Operator | Oct 2004 |
| 535 | Slant Operating, LLC | Lafayette, LA 70503 | Oil & Gas Operator | May 2025 |
| 536 | Smith, John A. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 537 | Sol Oil Co., L.C. | Crane, TX 79731 | Oil Operator | May 2025 |
| 538 | Southland Royalty Co.-Midland | Midland, TX 79702 | Oil & Gas Operator | Mar 1996 |
| 539 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 540 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 541 | Southwest-Operating | Penwell, TX 79776 | Oil & Gas Operator | May 2025 |
| 542 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 543 | Space Production Inc. | Monahans, TX 79756 | Oil & Gas Operator | May 2025 |
| 544 | Special Energy Corporation | Stillwater, OK 74076 | Oil & Gas Operator | May 2025 |
| 545 | Stanolind Operating Corp. | Midland, TX 79701 | Oil & Gas Operator | Apr 2008 |
| 546 | Stanolind Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Apr 2021 |
| 547 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 548 | Stephens, Mickie L. | MC Camey, TX 79752 | Oil & Gas Operator | Aug 1998 |
| 549 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 550 | Stout Energy Inc. | Midland, TX 79708 | Oil & Gas Operator | May 2025 |
| 551 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 552 | Stronghold Energy II Oper, LLC | Midland, TX 79702 | Oil & Gas Operator | Aug 2022 |
| 553 | Summit Exploration, L.L.C. | Tulsa, OK 74119 | Oil & Gas Operator | Mar 2008 |
| 554 | Summit Petroleum LLC | Midland, TX 79705 | Oil & Gas Operator | May 2025 |
| 555 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | May 2025 |
| 556 | Swanson, Tom | Electra, TX 76360 | Oil & Gas Operator | Oct 2004 |
| 557 | Swartz Oil Company | San Angelo, TX 76906 | Oil & Gas Operator | May 2025 |
| 558 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 559 | Talus Inc | Graham, TX 76450-1210 | Oil & Gas Operator | Feb 2017 |
| 560 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 561 | Taurus Petroleum, Inc. (A) | San Antonio, TX 78259 | Oil & Gas Operator | Jul 1996 |
| 562 | Taylor, Ben J. Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2022 |
| 563 | Taylor-McIlhenny Oper. Co., Inc. | Lewisville, TX 75029 | Oil & Gas Operator | Jan 1996 |
| 564 | TD Oil & Gas LLC | Duncan, OK 73533-1851 | Oil Operator | Apr 2023 |
| 565 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 566 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | May 2025 |
| 567 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | May 2025 |
| 568 | Tema Oil And Gas, LLC | Houston, TX 77040 | Oil & Gas Operator | Apr 2000 |
| 569 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | May 2025 |
| 570 | Texan Petroleum Corporation | Dallas, TX 75204 | Oil & Gas Operator | Oct 2004 |
| 571 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | May 2025 |
| 572 | Texas Secondary Oil Corporation | Devine, TX 78016 | Oil & Gas Operator | May 2025 |
| 573 | Texas Vanguard Oil Company | Austin, TX 78720 | Oil & Gas Operator | Jan 2014 |
| 574 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 575 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 576 | Three Span Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 577 | Three-B Oil Company, The | Monahans, TX 79756 | Oil & Gas Operator | May 2025 |
| 578 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 579 | TMBR/Sharp Drilling, Inc. | Midland, TX 79703 | Oil & Gas Operator | Feb 2004 |
| 580 | Toc Energy Resources, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | May 2025 |
| 581 | Tola Production Company | Dallas, TX 75367 | Oil & Gas Operator | May 2025 |
| 582 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 583 | Torch Energy Services, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 584 | Tres Roughneckas WTX LLC | MC Camey, TX 79752 | Oil Operator | May 2025 |
| 585 | Trey Services, Inc. | Midland, TX 79711 | Oil & Gas Operator | Dec 1996 |
| 586 | Triesco, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 1996 |
| 587 | Trinity Bay Oil & Gas, Inc. | Lubbock, TX 79416 | Oil & Gas Operator | May 2025 |
| 588 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 589 | Tripp & Sons, LLC | Odessa, TX 79768 | Oil & Gas Operator | May 2025 |
| 590 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 591 | Trivista Operating LLC | Giddings, TX 78942 | Oil & Gas Operator | May 2025 |
| 592 | Tumbleweed Energy Limited | Midland, TX 79704 | Oil & Gas Operator | Dec 2022 |
| 593 | TX Heat Of The Permian Basin Inc | Odessa, TX 79768 | Oil & Gas Operator | Dec 2021 |
| 594 | U S Energy Corp. Of Amer. Inc. | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 595 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | May 2025 |
| 596 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 597 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 598 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 599 | United Company | Lubbock, TX 79408 | Oil & Gas Operator | Jun 1995 |
| 600 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |