| 401 | Range Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2021 |
| 402 | Rasmussen, Hal J. Operating, Inc | Midland, TX 79701 | Oil & Gas Operator | Apr 2009 |
| 403 | Raw Oil & Gas, Inc. | Lubbock, TX 79401 | Oil & Gas Operator | Oct 2025 |
| 404 | Rayco Operating, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 405 | Rayden | Midland, TX 79711 | Oil & Gas Operator | Oct 2025 |
| 406 | Reach Oil And Gas Company Inc | Oklahoma City, OK 73118-1100 | Oil & Gas Operator | Jun 2025 |
| 407 | Reatta Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 408 | Red Willow Production, LLC | Ignacio, CO 81137 | Oil & Gas Operator | Oct 2015 |
| 409 | Regal Petroleum Services | Euless, TX 76039 | Oil & Gas Operator | Aug 2002 |
| 410 | Rein Pusher Operating LLC | Brenham, TX 77834 | Oil & Gas Operator | Oct 2025 |
| 411 | Reinecke Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | Nov 2018 |
| 412 | Remo, Inc. | Odessa, TX 79760 | Oil & Gas Operator | May 2003 |
| 413 | Renaud Oil Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 414 | Reo Operating LLC | Austin, TX 78747 | Oil & Gas Operator | Oct 2025 |
| 415 | Ricks Exploration, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2008 |
| 416 | Robert C. Brower, LLC | Southlake, TX 76092 | Oil & Gas Operator | Oct 2025 |
| 417 | Robertson Resources, Inc. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Oct 2025 |
| 418 | Rock Fish Operating LLC | McKinney, TX 75070 | Oil & Gas Operator | Oct 2025 |
| 419 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 420 | Rrig Exploration, LLC | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2025 |
| 421 | Ruwco Oil And Gas Corp. | Austin, TX 78701 | Oil & Gas Operator | Aug 2021 |
| 422 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 423 | Sabalo Operating, LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Jun 2021 |
| 424 | Sabinal Energy Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 425 | Sabre Oil Company, LLC | Boca Raton, FL 33487 | Oil & Gas Operator | Jun 2022 |
| 426 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Oct 2025 |
| 427 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 428 | Sayers Operating Company | Midland, TX 79705 | Oil & Gas Operator | Feb 2005 |
| 429 | Schlachter Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 430 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 431 | Schlachter, David A., Estate Of | Dallas, TX 75225 | Oil & Gas Operator | Jan 2000 |
| 432 | Schlagal, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2016 |
| 433 | Scout Energy Management LLC | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 434 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 435 | SDX Resources, Inc. | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 436 | Service Clearing Corp | Dallas, TX 75229 | Oil & Gas Operator | Oct 2025 |
| 437 | Sharp Image Energy, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Oct 2025 |
| 438 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 439 | Shenandoah Petroleum Corporation | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 440 | Shenandoah Resources LLC | Houston, TX 77086 | Oil & Gas Operator | Apr 2020 |
| 441 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Oct 2025 |
| 442 | Siana Oil & Gas | Conroe, TX 77305 | Oil & Gas Operator | Oct 2025 |
| 443 | Sierra Lima Oil & Gas, LLC | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 444 | Simmons, L.B. Energy, Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 2000 |
| 445 | Sinclair Oil & Gas Company | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Oct 2025 |
| 446 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Oct 2025 |
| 447 | Smith Brothers Oil & Gas, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 448 | Smith Energy Operating Company | Lubbock, TX 79423 | Oil & Gas Operator | Oct 2025 |
| 449 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Oct 2025 |
| 450 | Smith Vacuum Service | Snyder, TX 79550 | Oil & Gas Operator | Oct 2025 |
| 451 | Socorro Exploration, Inc. | Lubbock, TX 79464 | Oil & Gas Operator | Oct 2025 |
| 452 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 453 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 454 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 455 | Stallion Energy, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2017 |
| 456 | Star Production, Inc. | Dallas, TX 75360 | Oil & Gas Operator | Oct 2025 |
| 457 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 458 | STB Energy Inc. | Tulsa, OK 74105 | Oil & Gas Operator | Jul 2008 |
| 459 | Stephens & Johnson Operating Co. | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 460 | Stephens, Autry C. | Midland, TX 79701 | Oil & Gas Operator | Mar 2023 |
| 461 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 462 | Stickney Oil & Gas, Inc. | Midland, TX 79704 | Oil & Gas Operator | Nov 2014 |
| 463 | Stickney, F. C., Inc. | Midland, TX 79704 | Oil & Gas Operator | Oct 1998 |
| 464 | Strawn Energy Services, LLC | Lubbock, TX 79404 | Oil Operator | Oct 2025 |
| 465 | Success Oil Company, Inc. | Beverly Hills, CA 90211 | Oil & Gas Operator | Oct 2025 |
| 466 | Surge Operating, LLC | Houston, TX 77041 | Oil & Gas Operator | Oct 2025 |
| 467 | Tacor Resources Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 468 | Tall City Operations LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2016 |
| 469 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 470 | Targa Pipeline Mid-Continent LLC | Sulphur, LA 70665 | Oil & Gas Operator | Jun 2018 |
| 471 | Taurus Exploration U.S.A., Inc. | Midland, TX 79705 | Oil & Gas Operator | Nov 1998 |
| 472 | TC Energy LLC | Covington, OK 73730-2116 | Oil & Gas Operator | Sep 2014 |
| 473 | TD Oil & Gas LLC | Duncan, OK 73533-1851 | Oil Operator | Apr 2023 |
| 474 | Telesis Operating Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Oct 2025 |
| 475 | Tenison Oil Company | Abilene, TX 79605 | Oil & Gas Operator | Jun 2025 |
| 476 | Teon Management, LLC | Midland, TX 79704 | Oil & Gas Operator | Mar 2020 |
| 477 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 478 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 479 | Texas Energy Sources, Inc. | Midland, TX 79708 | Oil & Gas Operator | Mar 2008 |
| 480 | Texas Mineral Group | Midland, TX 79705 | Oil & Gas Operator | Aug 2013 |
| 481 | Texland-Rector & Schumacher | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2000 |
| 482 | Thompson, J. Cleo | Dallas, TX 75201 | Oil & Gas Operator | May 2024 |
| 483 | Three Rivers Operating Co LLC | Austin, TX 78735 | Oil & Gas Operator | Mar 2017 |
| 484 | Three Span Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 485 | Tindle Petroleum LLC | Midland, TX 79701 | Oil & Gas Operator | Jan 2023 |
| 486 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 487 | TMBR/Sharp Drilling, Inc. | Midland, TX 79703 | Oil & Gas Operator | Feb 2004 |
| 488 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 489 | Trilogy Operating, Inc. | Midland, TX 79708 | Oil & Gas Operator | Oct 2025 |
| 490 | Trinidad Resources, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 491 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 492 | Triple "N" Services, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 493 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 494 | Tumbleweed Energy Limited | Midland, TX 79704 | Oil & Gas Operator | Dec 2022 |
| 495 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | Oct 2025 |
| 496 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 497 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 498 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 499 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Oct 2025 |
| 500 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |