| 1 | Halbouty, Michel T. | Houston, TX 77056 | Oil & Gas Operator | Aug 1997 |
| 2 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 3 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Dec 2024 |
| 4 | Hampton Resources Corporation | Houston, TX 77010 | Oil & Gas Operator | Mar 1996 |
| 5 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 6 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 7 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 8 | Hardy Oil & Gas USA Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 1996 |
| 9 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 10 | Heisey Ventures, Inc. | Houston, TX 77019 | Oil & Gas Operator | Dec 2024 |
| 11 | Heritage Expl. & Prod. Co., Inc. | Stafford, TX 77497 | Oil & Gas Operator | Dec 2000 |
| 12 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 13 | Highmark Energy Operating, LLC | Poynor, TX 75782 | Oil & Gas Operator | Dec 2024 |
| 14 | Hill Production Co Inc-Wisconsin | Humble, TX 77347 | Oil & Gas Operator | Jun 1993 |
| 15 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 16 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 17 | Hooper, DR. Oil & Royalty Co. | Conroe, TX 77304 | Oil & Gas Operator | Sep 1999 |
| 18 | Hopco Operating, Inc. | Stafford, TX 77497 | Oil & Gas Operator | Dec 2016 |
| 19 | Houston Hydrocarbons, Inc. (A) | Houston, TX 77042 | Oil & Gas Operator | Sep 2004 |
| 20 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2024 |