| 1 | H & S Production, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Mar 2004 |
| 2 | H & T Exploration, Inc. | Longview, TX 75605 | Oil & Gas Operator | Oct 2025 |
| 3 | Halo Energy L.L.C. | Kilgore, TX 75662 | Oil Operator | Oct 2025 |
| 4 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 5 | Harleton Oil & Gas Inc. | Tyler, TX 75710 | Oil & Gas Operator | Oct 2025 |
| 6 | Harman Operating Company, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2007 |
| 7 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 8 | Heritage Energy Corporation | Waco, TX 76710 | Oil & Gas Operator | Sep 2004 |
| 9 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 10 | Hopkins, T. M. Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 11 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 12 | Howell Oil & Gas, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Oct 2019 |
| 13 | HPC Operating, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Mar 2008 |
| 14 | Hrubetz Operating Company | Dallas, TX 75225 | Oil & Gas Operator | Feb 1999 |
| 15 | Hugus Investment Company, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Oct 2025 |
| 16 | Hulsey Oil Company | Dallas, TX 75205 | Oil & Gas Operator | Aug 1999 |
| 17 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 18 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 19 | Hunt, WM. Herbert, Trust Est. | Dallas, TX 75201 | Oil & Gas Operator | Sep 1998 |
| 20 | Huntington Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2006 |