| 1 | H & S Production, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Mar 2004 |
| 2 | H-M Resource Management, Inc. | Houston, TX 77055 | Oil & Gas Operator | Feb 2023 |
| 3 | Ha.P.C. Oil, Inc. | Gonzales, TX 78629 | Oil & Gas Operator | Aug 2006 |
| 4 | Haas, C. F. Oil & Gas Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 5 | Halbouty, Michel T. | Houston, TX 77056 | Oil & Gas Operator | Aug 1997 |
| 6 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 7 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 8 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 9 | Hankey Oil Company | Houston, TX 77027 | Oil & Gas Operator | Feb 2010 |
| 10 | Hankey Operating, Inc. | Houston, TX 77027 | Oil & Gas Operator | Mar 2016 |
| 11 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 12 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 13 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 14 | Haring Energy Company | Tuleta, TX 78162 | Oil & Gas Operator | Mar 2003 |
| 15 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 16 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 17 | Hart Petroleum Services, Inc | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jul 2025 |
| 18 | Harvey Brothers Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Jul 2004 |
| 19 | Harwood Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 20 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 21 | Hazoco, L.L.C. | Bellville, TX 77418 | Oil Operator | Oct 2025 |
| 22 | Henry, J.R. Inc | Brenham, TX 77833 | Oil & Gas Operator | Oct 2025 |
| 23 | Hermat Salt Water Disposal, Inc. | Corpus Chrsti, TX 78426 | Oil Operator | Aug 2012 |
| 24 | Hewitt, Robert J. | Victoria, TX 77901 | Oil & Gas Operator | Jun 2004 |
| 25 | Hgi Corporation | Nada, TX 77460 | Oil & Gas Operator | Apr 2016 |
| 26 | Hibbard Energy, LP | Whitehouse, TX 75791 | Oil & Gas Operator | Oct 2025 |
| 27 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 28 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 29 | Holloway Oil Company | Austin, TX 78764 | Oil & Gas Operator | Feb 2004 |
| 30 | Horizon Prod. And Operating, LLC | Houston, TX 77019 | Oil & Gas Operator | Oct 2025 |
| 31 | Houston Energy, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 32 | Houston Gulf Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 33 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 34 | Houston Operating, Inc. | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 35 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Oct 2025 |
| 36 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 37 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Oct 2025 |
| 38 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 39 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 40 | Hunt, WM. Herbert, Trust Est. | Dallas, TX 75201 | Oil & Gas Operator | Sep 1998 |
| 41 | Hunter Petroleum Inc. | Alice, TX 78333 | Oil & Gas Operator | May 2014 |
| 42 | Hurd Ent.LTD/U.S.Enercorp,LLC | San Antonio, TX 78209 | Oil & Gas Operator | Aug 2002 |
| 43 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 44 | Hydrocarbon Horizons, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Jun 2023 |
| 45 | Hydrocarbon Operating, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 46 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |