| 1 | Taurus Petroleum | | Oil & Gas Operator | Jul 1987 |
| 2 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 3 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 4 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 5 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 6 | Texas Eastern Transm. Corp. | | Oil & Gas Operator | Dec 2002 |
| 7 | Texoil Company | | Oil & Gas Operator | Dec 2000 |
| 8 | The B&C Corp-Imp Amer MGT Co | | Oil & Gas Operator | Aug 1981 |
| 9 | The Dow Chemical Company | | Oil & Gas Operator | Dec 1997 |
| 10 | Tiger Oil Company | Dallas, TX 75221 | Oil & Gas Operator | May 2007 |
| 11 | Tiger Oil International, Inc | | Oil & Gas Operator | Dec 1978 |
| 12 | Tiger Petroleum | | Oil Operator | Sep 2002 |
| 13 | Tipco | Shreveport, LA 71104-3047 | Oil & Gas Operator | May 1988 |
| 14 | Toce Energy, L.L.C. | | Oil & Gas Operator | Dec 2017 |
| 15 | Toce Oil Company | | Oil & Gas Operator | Dec 2014 |
| 16 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 17 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 18 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 19 | Transcontinental Gas P/L Corp. | | Oil & Gas Operator | Dec 2009 |
| 20 | Transcontinental Gas Pipeline Co LLC | | Oil Operator | Jan 2025 |
| 21 | Tribal Oil Company | | Oil & Gas Operator | Dec 1981 |
| 22 | Triumph Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Nov 2015 |
| 23 | TXP Operating Company | | Oil & Gas Operator | Jul 1992 |