| 301 | Union Gas Operating Company | Houston, TX 77014 | Oil & Gas Operator | Oct 2025 |
| 302 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 303 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Jun 2025 |
| 304 | Ursus Oil And Gas | Tyler, TX 75703 | Oil & Gas Operator | Oct 2025 |
| 305 | Usfg Oil & Gas, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Dec 2005 |
| 306 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Oct 2025 |
| 307 | Van Oil Co Inc | Fort Worth, TX 76116 | Oil Operator | Dec 1997 |
| 308 | Venus Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2002 |
| 309 | Verado Energy, Inc. | Allen, TX 75013 | Oil & Gas Operator | Oct 2025 |
| 310 | Vinland Texas Services LLC | Electra, TX 76360 | Oil & Gas Operator | Jun 2024 |
| 311 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 312 | Vintage Petroleum, LLC | Houston, TX 77210 | Oil & Gas Operator | Dec 2019 |
| 313 | Wagner & Brown, LTD. | Midland, TX 79702 | Oil & Gas Operator | Aug 2014 |
| 314 | Walker'S Well Service | Gladewater, TX 75647 | Oil & Gas Operator | Aug 2003 |
| 315 | Weatherly Oil & Gas, LLC | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 316 | Weiser-Brown Oil Co | Magnolia, AR 71754 | Oil Operator | Jan 2025 |
| 317 | West Mountain Operating Co, Inc. | Longview, TX 75604 | Oil & Gas Operator | Feb 2019 |
| 318 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 319 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 320 | Wilcox Operating Corporation | Shreveport, LA 71115 | Oil & Gas Operator | Oct 2025 |
| 321 | Wilson Hydrocarbon Inc. | Houston, TX 77066 | Oil & Gas Operator | Oct 2025 |
| 322 | Winchester Production Company | Shreveport, LA 71129 | Oil & Gas Operator | Nov 2008 |
| 323 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 324 | Zivney Energy | White Oak, TX 75693 | Oil & Gas Operator | Oct 2025 |
| 325 | ZTH Operating, LLC | Troup, TX 75789 | Oil & Gas Operator | Oct 2025 |