| 1 | Hall-Houston Oil Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 2 | Harper, Wayne | Dallas, TX 75206 | Oil & Gas Operator | Mar 2008 |
| 3 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | Dec 2024 |
| 4 | Hemco Development, LLC | Dallas, TX 75201 | Oil & Gas Operator | Nov 2020 |
| 5 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 6 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Dec 2024 |
| 7 | Horizon Exploration Company | Houston, TX 77019 | Oil & Gas Operator | Aug 2002 |
| 8 | Houston Hydrocarbons, Inc. (A) | Houston, TX 77042 | Oil & Gas Operator | Sep 2004 |
| 9 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 10 | Houston Oil Prod Enterprises,Inc | Houston, TX 77006 | Oil & Gas Operator | Dec 2024 |
| 11 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 12 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Dec 2024 |
| 13 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 14 | Humphrey, Thos.D. Oil Prop.,Inc. | Gainesville, TX 76241 | Oil & Gas Operator | Aug 1999 |
| 15 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2024 |