| 1 | H & T Exploration, Inc. | Longview, TX 75605 | Oil & Gas Operator | Oct 2025 |
| 2 | Halcon Resources Operating, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2013 |
| 3 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 4 | Halo Energy L.L.C. | Kilgore, TX 75662 | Oil Operator | Oct 2025 |
| 5 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 6 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Oct 2025 |
| 7 | Hardy Ranch, Inc. | Henderson, TX 75654 | Oil & Gas Operator | Oct 2025 |
| 8 | Harleton Oil & Gas Inc. | Tyler, TX 75710 | Oil & Gas Operator | Oct 2025 |
| 9 | Harman Operating Company, Inc. | Tyler, TX 75702 | Oil & Gas Operator | Dec 2007 |
| 10 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 11 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 12 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 13 | Heritage Energy Corporation | Waco, TX 76710 | Oil & Gas Operator | Sep 2004 |
| 14 | Herv Oil, LLC | Oklahoma City, OK 73116 | Oil Operator | Jun 2025 |
| 15 | Hibbard Energy, LP | Whitehouse, TX 75791 | Oil & Gas Operator | Oct 2025 |
| 16 | Highmark Energy Operating, LLC | Dallas, TX 75222 | Oil & Gas Operator | Oct 2025 |
| 17 | Hightower Exploration | Kilgore, TX 75662 | Oil & Gas Operator | Oct 2025 |
| 18 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 19 | Hill Production Company | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2009 |
| 20 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 21 | Hinton Production Company | MT Pleasant, TX 75455 | Oil & Gas Operator | Aug 1995 |
| 22 | Hodge T F | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2007 |
| 23 | Holt Oil And Cattle LLC | Bedias, TX 77831 | Oil & Gas Operator | Oct 2025 |
| 24 | Hombre Oil Co., LTD. | Tyler, TX 75713 | Oil & Gas Operator | Apr 2021 |
| 25 | Hopkins, T. M. Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 26 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 27 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 28 | Howell & Sandlin, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Jan 2001 |
| 29 | Howell Oil & Gas, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Oct 2019 |
| 30 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Oct 2025 |
| 31 | Hrubetz Operating Company | Dallas, TX 75225 | Oil & Gas Operator | Feb 1999 |
| 32 | Hughey, Gaylord T. SR. Oper. Co. | Tyler, TX 75711 | Oil & Gas Operator | Feb 1998 |
| 33 | Hughey, W. R., Operating Co. | Tyler, TX 75711 | Oil & Gas Operator | Feb 2005 |
| 34 | Hugus Investment Company, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Oct 2025 |
| 35 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 36 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 37 | Hunt, WM. Herbert, Trust Est. | Dallas, TX 75201 | Oil & Gas Operator | Sep 1998 |
| 38 | Huntington Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2006 |
| 39 | Hydrocarbon Lease Management LTD | Addison, TX 75001 | Oil & Gas Operator | Jul 2002 |
| 40 | Hydrogeo, L.L.C. | Houston, TX 77074 | Oil & Gas Operator | Oct 2025 |