| 101 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |
| 102 | SWN Production Company, LLC | Spring, TX 77391 | Oil & Gas Operator | Sep 2024 |
| 103 | Tbi Production Company | Lakewood, CO 80228 | Oil & Gas Operator | Oct 2004 |
| 104 | Texaco Expl. And Prod. Inc. | Houston, TX 77236 | Oil & Gas Operator | Aug 2024 |
| 105 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Oct 2024 |
| 106 | Thomas Operating Company Inc | Greeley, CO 80634 | Oil & Gas Operator | Aug 2008 |
| 107 | Thorofare Resources, Inc | | Oil & Gas Operator | May 2011 |
| 108 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Dec 2024 |
| 109 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Dec 2023 |
| 110 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 111 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 112 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Oct 2024 |
| 113 | Vaquero Energy Inc | Bakersfield, CA 93309 | Oil & Gas Operator | May 2023 |
| 114 | Vitruvian Exploration LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2016 |
| 115 | Voyager Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 116 | Wesco Operating, Inc. | Casper, WY 82602 | Oil & Gas Operator | Oct 2024 |
| 117 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |
| 118 | Western Gas Resources Inc | Denver, CO 80202-1955 | Oil & Gas Operator | Dec 2007 |
| 119 | Western Gas Resources-Sand Wash Inc | | Oil & Gas Operator | Feb 2008 |
| 120 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2020 |
| 121 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 122 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Oct 2024 |
| 123 | Wexpro Development Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Oct 2024 |
| 124 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 125 | Winter Ridge Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2011 |
| 126 | Wold Oil Properties Inc | Denver, CO 80203 | Oil & Gas Operator | Feb 2018 |
| 127 | Wolverine Resources LLC | | Oil & Gas Operator | Jan 2024 |
| 128 | Wyman* Louis M Dba Wyman Inc | | Oil & Gas Operator | Nov 2024 |
| 129 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 130 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | Dec 2024 |