| 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 | Haas, C. F. Oil & Gas Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Jul 2025 |
| 4 | Haber Resources Corporation | Houston, TX 77063 | Oil & Gas Operator | Mar 1999 |
| 5 | Halbouty, Michel T. | Houston, TX 77056 | Oil & Gas Operator | Aug 1997 |
| 6 | Halcon Resources Operating, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2013 |
| 7 | Hall-Houston Oil Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 8 | Hamill Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1999 |
| 9 | Hamill, Claud B. Estate Of | Houston, TX 77002 | Oil & Gas Operator | Nov 1995 |
| 10 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Jul 2025 |
| 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 | Harrison, Sam G. Oil, Inc. | Houston, TX 77019 | Oil & Gas Operator | Nov 2019 |
| 15 | Harvest Petroleum Inc. | Frisco, TX 75033 | Oil & Gas Operator | Jul 2025 |
| 16 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 17 | Hazoco, L.L.C. | Bellville, TX 77418 | Oil Operator | Jul 2025 |
| 18 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 19 | Headline Resources, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Aug 1997 |
| 20 | Hennig Production Co., Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jul 2025 |
| 21 | Hewitt, Robert J. | Victoria, TX 77901 | Oil & Gas Operator | Jun 2004 |
| 22 | Hgi Corporation | Nada, TX 77460 | Oil & Gas Operator | Apr 2016 |
| 23 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2025 |
| 24 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 25 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Jul 2025 |
| 26 | Horizon Exploration Company | Houston, TX 77019 | Oil & Gas Operator | Aug 2002 |
| 27 | Houston Expl. & Prod. Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Aug 2003 |
| 28 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 29 | Houston Gulf Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Jul 2025 |
| 30 | Houston Hydrocarbons, Inc. (A) | Houston, TX 77042 | Oil & Gas Operator | Sep 2004 |
| 31 | Houston Oil & Gas Company, Inc. | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 32 | Houston Operating, Inc. | Houston, TX 77027 | Oil & Gas Operator | Jul 2025 |
| 33 | Houston Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | Jul 2025 |
| 34 | Houston Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | Apr 2003 |
| 35 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | Jul 2025 |
| 36 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 37 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Jul 2025 |
| 38 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 39 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Jul 2025 |
| 40 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 41 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 42 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 43 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 44 | Hurricane Oil And Gas Co., Inc. | Houston, TX 77057 | Oil & Gas Operator | Mar 2008 |
| 45 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |