| 301 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 302 | Uosi Operating, Inc. | Lovelady, TX 75851 | Oil & Gas Operator | Mar 2025 |
| 303 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Mar 2025 |
| 304 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2025 |
| 305 | Valley Resources, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Aug 2003 |
| 306 | Vinland Texas Services LLC | Electra, TX 76360 | Oil & Gas Operator | Jun 2024 |
| 307 | Viola Prod., Inc. | Dallas, TX 75251 | Oil & Gas Operator | Mar 2025 |
| 308 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 309 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 310 | Warrior Petroleum Corporation | Henderson, TX 75652 | Oil & Gas Operator | Apr 2024 |
| 311 | Watkins Production Company | Dallas, TX 75229 | Oil & Gas Operator | Feb 2008 |
| 312 | Weatherly Oil & Gas, LLC | Dallas, TX 75206 | Oil & Gas Operator | Mar 2025 |
| 313 | Weathers Exploration, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Mar 2025 |
| 314 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 315 | Western Chief Operating, L.L.C. | Graham, TX 76450 | Oil & Gas Operator | Mar 2025 |
| 316 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 317 | Wheeler Operating Corporation | Fort Worth, TX 76101 | Oil & Gas Operator | Mar 2025 |
| 318 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Mar 2025 |
| 319 | Williams, Clayton W., Jr., Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 320 | Wilson Hydrocarbon Inc. | Houston, TX 77066 | Oil & Gas Operator | Mar 2025 |
| 321 | Wilson, Don H., Inc. | Elkhart, TX 75839 | Oil & Gas Operator | May 2019 |
| 322 | Wind River Resources Inc | Tulsa, OK 74136-6381 | Oil & Gas Operator | Jun 2010 |
| 323 | Wing Corporation | Houston, TX 77002 | Oil & Gas Operator | Jun 2000 |
| 324 | Winn Exploration Co., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2025 |
| 325 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 326 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |