| 201 | Tarpon Oil Company | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2017 |
| 202 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 203 | Texas Tea Of Colorado LLC Dba Texas Tea LLC | | Oil & Gas Operator | Jun 2021 |
| 204 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Aug 2025 |
| 205 | Thomas Operating Company Inc | Greeley, CO 80634 | Oil & Gas Operator | Aug 2008 |
| 206 | Thorofare Resources, Inc | | Oil & Gas Operator | May 2011 |
| 207 | Tidal Wave Energy, Inc. | New Castle, PA 16105 | Oil & Gas Operator | Jun 2022 |
| 208 | Tigges Oil LLC | | Oil & Gas Operator | Dec 2022 |
| 209 | Timka Resources LTD | | Oil & Gas Operator | Aug 2025 |
| 210 | Tindall Operating Company | Englewood, CO 80112 | Oil & Gas Operator | Jan 2025 |
| 211 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 212 | Top Operating Company | | Oil & Gas Operator | Oct 2022 |
| 213 | Trinity Energy Corp | Gibsonia, PA 15044-9106 | Oil & Gas Operator | Dec 2007 |
| 214 | Triple R Oil Co | | Oil & Gas Operator | Jun 2002 |
| 215 | Tudex Petroleum Inc | | Oil & Gas Operator | Sep 2019 |
| 216 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |
| 217 | United States Exploration, Inc. | Denver, CO 80802 | Oil & Gas Operator | Jun 2009 |
| 218 | Upland Exploration, LLC | Boerne, TX 78006 | Oil & Gas Operator | Jul 2024 |
| 219 | Valley Operating Inc | Denver, CO 80218-3633 | Oil & Gas Operator | Jan 2004 |
| 220 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2021 |
| 221 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 222 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Oct 2025 |
| 223 | Verdad Resources LLC | | Oil & Gas Operator | Jul 2025 |
| 224 | Walker Oil & Gas Co LLC* Keith F | | Oil & Gas Operator | Jun 2011 |
| 225 | Walsh Production Inc | | Oil & Gas Operator | Nov 2008 |
| 226 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jun 2025 |
| 227 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Jul 2025 |
| 228 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Jul 2025 |
| 229 | Whitewing Resources LLC | | Oil & Gas Operator | Jun 2014 |
| 230 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 231 | Wind River Exploration Inc | Sewickley, PA 15143 | Oil & Gas Operator | Jun 2025 |
| 232 | Windsor Energy Group LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Aug 2021 |
| 233 | Wy Woodland Operating, LLC | Covington, TX 76636 | Oil & Gas Operator | Oct 2025 |