| 401 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 402 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 403 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 404 | Unitex Oil & Gas, L.L.C. | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 405 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Dec 2025 |
| 406 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 407 | Ventex Operating Corp. | Addison, TX 75001 | Oil & Gas Operator | Dec 2025 |
| 408 | Viejo Oil & Gas, LLC | Post, TX 79356 | Oil Operator | Dec 2025 |
| 409 | Viking Energy Corporation | Odessa, TX 79760 | Oil & Gas Operator | Dec 2021 |
| 410 | Voyager Gas Corporation | Spring, TX 77379 | Oil & Gas Operator | Feb 2012 |
| 411 | W&W Oil Co | Denver City, TX 79323 | Oil Operator | Jun 2002 |
| 412 | W.H.D., Inc. | Euless, TX 76039 | Oil & Gas Operator | Aug 1998 |
| 413 | Walsh & Watts Inc | Aledo, TX 76008 | Oil & Gas Operator | Dec 2025 |
| 414 | Walter Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | May 2009 |
| 415 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 416 | West Inland Energy, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Dec 2025 |
| 417 | West Texas Oil And Gas Oper.,Inc | Houston, TX 77046 | Oil & Gas Operator | Jul 2024 |
| 418 | Western Reserves Oil Co Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2020 |
| 419 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 420 | Wheeler Operating Corporation | Fort Worth, TX 76109 | Oil & Gas Operator | Dec 2025 |
| 421 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 422 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 423 | Winn Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 424 | WJC, Inc. | Post, TX 79356 | Oil & Gas Operator | Dec 2025 |
| 425 | WMS Oil Company | Post, TX 79356 | Oil & Gas Operator | May 2019 |
| 426 | WTG Exploration | Midland, TX 79705 | Oil & Gas Operator | Dec 2025 |
| 427 | WTG Exploration Inc | Midland, TX 79705 | Oil & Gas Operator | Dec 2023 |
| 428 | WTP Energy, Inc. | Snyder, TX 79549 | Oil & Gas Operator | Dec 2025 |
| 429 | Wynn-Crosby Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 430 | Xeric Oil & Gas Company | Midland, TX 79702 | Oil & Gas Operator | Jul 1997 |
| 431 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 432 | Yates Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | Dec 2025 |
| 433 | Young Marshall R Oil Co | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2011 |
| 434 | Zachry Oil And Gas Properties | Midland, TX 79708 | Oil & Gas Operator | Dec 2025 |
| 435 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |