| 1 | T-Boc Inc. | | Oil & Gas Operator | Apr 2016 |
| 2 | T2 Operating Corporation | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 3 | Taqa USA, Inc. | Centennial, CO 80111 | Oil & Gas Operator | Jul 2020 |
| 4 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2025 |
| 5 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 6 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 7 | Texakota, Inc. | Houston, TX 77098 | Oil & Gas Operator | Mar 2021 |
| 8 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 9 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 10 | Thunderbird Resources LP | | Oil & Gas Operator | Apr 2019 |
| 11 | Tiger Oil Company | Dallas, TX 75221 | Oil & Gas Operator | May 2007 |
| 12 | Timberline Production Company LLC | Casper, WY 82601 | Oil & Gas Operator | Oct 2020 |
| 13 | Titan Energy, LLC | | Oil & Gas Operator | Aug 2025 |
| 14 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 15 | Top Operating Company | | Oil & Gas Operator | Oct 2022 |
| 16 | Tracker Resource Development II, LLC | | Oil & Gas Operator | Feb 2011 |
| 17 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 18 | Traverse Oil Co. | | Oil & Gas Operator | Nov 1983 |
| 19 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Oct 2025 |
| 20 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 21 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 22 | Triangle USA Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 2021 |
| 23 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 24 | True Oil Company | Casper, WY 82602 | Oil & Gas Operator | Aug 2003 |
| 25 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Aug 2025 |
| 26 | Turtle Mountain Gas & Oil, Inc. | | Oil & Gas Operator | Oct 2006 |
| 27 | TXP Operating Company | | Oil & Gas Operator | Jul 1992 |
| 28 | Tyrex Oil Company | Casper, WY 82602 | Oil & Gas Operator | May 1997 |