| 1 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 2 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 3 | Harleton Oil & Gas Inc. | Tyler, TX 75710 | Oil & Gas Operator | Dec 2024 |
| 4 | Harwood Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 5 | Hawn Brothers Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jan 2003 |
| 6 | Headington Energy Partners, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2024 |
| 7 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 8 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 9 | Herschap Bros. | Bruni, TX 78344 | Oil & Gas Operator | Dec 2024 |
| 10 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Dec 2024 |
| 11 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Dec 2024 |
| 12 | Hugoton Operating Company, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Dec 2024 |
| 13 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2024 |
| 14 | Hunter & Hedrick Production, Inc | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 1995 |
| 15 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2024 |