| 201 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 202 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 203 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Dec 2025 |
| 204 | Texakota, Inc. | Houston, TX 77098 | Oil & Gas Operator | Mar 2021 |
| 205 | Texcal Oil Inc. | Vidor, TX 77662 | Oil & Gas Operator | Jun 1994 |
| 206 | Tharp Operating Company | Houston, TX 77070 | Oil & Gas Operator | Nov 2014 |
| 207 | Three Forks Resources, LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Dec 2025 |
| 208 | Tipperary Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 209 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 210 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Dec 2025 |
| 211 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 212 | Union Gas Operating Company | Spring, TX 77391 | Oil & Gas Operator | Dec 2025 |
| 213 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 214 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 215 | Upstream Exploration LLC | Metairie, LA 70002 | Oil & Gas Operator | Jan 2020 |
| 216 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Dec 2025 |
| 217 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Sep 2025 |
| 218 | Venus Oil Company | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2002 |
| 219 | Viesca Gas Co. | Spring, TX 77379 | Oil & Gas Operator | Dec 2025 |
| 220 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 221 | Weatherly Oil & Gas, LLC | Dallas, TX 75206 | Oil & Gas Operator | Dec 2025 |
| 222 | West Petroleum Corp. | San Antonio, TX 78205 | Oil & Gas Operator | Oct 2009 |
| 223 | Western Energy Group, LLC | Leander, TX 78641 | Oil & Gas Operator | Dec 2025 |
| 224 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 225 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Dec 2025 |
| 226 | White Rock Oil & Gas, LLC | Plano, TX 75024 | Oil & Gas Operator | Dec 2025 |
| 227 | Whitehead Prod. Co., Inc. | Humble, TX 77338 | Oil & Gas Operator | Oct 2025 |
| 228 | Whitehead Resources, LTD. | Buna, TX 77612 | Oil & Gas Operator | Dec 2025 |
| 229 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 230 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 231 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 232 | Zinn Petroleum Co. | Houston, TX 77024 | Oil & Gas Operator | Nov 2021 |