| 1 | H & P Exploration Co. | Alice, TX 78333 | Oil & Gas Operator | May 2019 |
| 2 | H H Exploration, Inc. | Incline VLLG, NV 89451 | Gas Operator | Feb 2018 |
| 3 | Haas, C. F. Oil & Gas Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 4 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 5 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 6 | Haring Energy Company | Tuleta, TX 78162 | Oil & Gas Operator | Mar 2003 |
| 7 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 8 | Harrigan Operating, LLC | Houston, TX 77258 | Oil & Gas Operator | Apr 2020 |
| 9 | Harris Energy Services, LLC | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 10 | Hart Petroleum Services, Inc | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jul 2025 |
| 11 | Harvey Brothers Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Jul 2004 |
| 12 | Harvey, Mike W. Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Aug 2003 |
| 13 | Harwood Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 14 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 15 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 16 | Hays, T.G. Petroleum Expl., Inc. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Dec 1994 |
| 17 | Hazelett Oil Company, Inc. | Dale, TX 78616 | Oil & Gas Operator | Sep 2005 |
| 18 | Hazelett Oil, Inc. | Dale, TX 78616 | Oil & Gas Operator | Aug 2024 |
| 19 | Heartland Resources, Inc. | Temple, TX 76501 | Oil & Gas Operator | Mar 2008 |
| 20 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 21 | Hedrick Production Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 22 | Hewitt, Robert J. | Victoria, TX 77901 | Oil & Gas Operator | Jun 2004 |
| 23 | High Island Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Jun 2017 |
| 24 | High Plains Gas Systems, Inc. | Houston, TX 77019 | Oil & Gas Operator | Oct 2025 |
| 25 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 26 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 27 | Horizon Exploration Company | Houston, TX 77019 | Oil & Gas Operator | Aug 2002 |
| 28 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | Oct 2025 |
| 29 | Howard, Douglas J. | Houston, TX 77070 | Oil & Gas Operator | Mar 2008 |
| 30 | Huber Energy L.P. | Houston, TX 77079 | Oil & Gas Operator | Feb 2007 |
| 31 | Huber Energy Panhandle LP | Houston, TX 77079 | Oil & Gas Operator | Oct 2005 |
| 32 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 33 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 34 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Oct 2025 |
| 35 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 36 | Hunter & Hedrick Production, Inc | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 1995 |
| 37 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 38 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |