| 401 | Tecolote Energy Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jan 2024 |
| 402 | Tess Oil Company | Borger, TX 79008 | Oil & Gas Operator | Mar 2008 |
| 403 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Feb 2026 |
| 404 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Feb 2026 |
| 405 | Texas Operating Partners LLC | Tomball, TX 77377 | Oil & Gas Operator | Feb 2026 |
| 406 | Texian Energy Corporation | Amarillo, TX 79120 | Oil & Gas Operator | Apr 1997 |
| 407 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 408 | The Operating Co. | Pampa, TX 79065 | Oil & Gas Operator | Sep 2007 |
| 409 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Dec 2025 |
| 410 | TJ Oil Company | Borger, TX 79008 | Oil & Gas Operator | Feb 2026 |
| 411 | Tom Coble Oil & Gas LP | Amarillo, TX 79105 | Oil & Gas Operator | Feb 2026 |
| 412 | Toney, W.L. | Borger, TX 79007 | Oil & Gas Operator | Oct 2012 |
| 413 | Topper Oil Company | Borger, TX 79007 | Oil & Gas Operator | Feb 2026 |
| 414 | Trans Terra Corp., International | Amarillo, TX 79159 | Oil & Gas Operator | Feb 2009 |
| 415 | Travelers Oil Company | Amarillo, TX 79102 | Oil & Gas Operator | Feb 2026 |
| 416 | Trojan Oil And Gas | White Deer, TX 79097 | Oil & Gas Operator | Dec 1994 |
| 417 | Tryma Operating | Borger, TX 79008 | Oil & Gas Operator | Feb 2026 |
| 418 | TTL Energy Resources, Inc. | Borger, TX 79008 | Oil & Gas Operator | Aug 2013 |
| 419 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 420 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 421 | Untamed Resources, LLC | Spearman, TX 79081 | Gas Operator | Feb 2026 |
| 422 | Upland Resources LLC | Canadian, TX 79014 | Oil & Gas Operator | Feb 2026 |
| 423 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 424 | Vitol Inc. | Houston, TX 77098 | Oil & Gas Operator | Sep 2023 |
| 425 | VRK Oil And Gas, Inc. | Arlington, TX 76016 | Oil & Gas Operator | Mar 2014 |
| 426 | W. B. D. Oil & Gas Company | Pampa, TX 79066 | Oil & Gas Operator | Dec 1995 |
| 427 | W.B.D. Oil And Gas Inc. | Pampa, TX 79066 | Oil & Gas Operator | Oct 2019 |
| 428 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 429 | Walls, G. M. & Frances, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 430 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Feb 2026 |
| 431 | Watkins, J. B. | Borger, TX 79007 | Oil & Gas Operator | May 2009 |
| 432 | Watson Operating Company | Pampa, TX 79066 | Oil & Gas Operator | Dec 2003 |
| 433 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Dec 2025 |
| 434 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 435 | WG Operating, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | May 2012 |
| 436 | Wheeler Oil Co. (A) | Amarillo, TX 79114 | Gas Operator | Apr 2001 |
| 437 | Whitlock, J.R. Operator | Amarillo, TX 79105 | Gas Operator | Jul 1997 |
| 438 | Whittington, G. R. | Amarillo, TX 79109 | Oil & Gas Operator | Jan 1994 |
| 439 | Whittington, G. R. Estate | Amarillo, TX 79109 | Oil & Gas Operator | Mar 2008 |
| 440 | Wilbanks Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 441 | Wilco Properties, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Jan 2004 |
| 442 | Winchester Oil & Gas LLC | Rockdale, TX 76567 | Oil Operator | Feb 2026 |
| 443 | Wind River Resources Inc | Tulsa, OK 74136-6381 | Oil & Gas Operator | Jun 2010 |
| 444 | Wischkaemper, Kenneth | Shamrock, TX 79079 | Oil & Gas Operator | Feb 2026 |
| 445 | Wo Operating Company | Tulsa, OK 74159 | Oil & Gas Operator | Feb 2026 |
| 446 | Wylie, Fred, Jr. | Moran, TX 76464 | Oil & Gas Operator | Oct 2022 |
| 447 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |