| 1 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 2 | Harvest Petroleum Inc. | Frisco, TX 75033 | Oil & Gas Operator | Oct 2025 |
| 3 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 4 | Henderson, Peter Oil Co. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 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 | Oct 2025 |
| 7 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 8 | Houston Energy Operating, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jul 2020 |
| 9 | Houston Gulf Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 10 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 11 | Houston Oil Prod Enterprises,Inc | Houston, TX 77006 | Oil & Gas Operator | Oct 2025 |
| 12 | Houston Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 13 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | Oct 2025 |
| 14 | Howard, Douglas J. | Houston, TX 77070 | Oil & Gas Operator | Mar 2008 |
| 15 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 16 | HRB Oil | Houston, TX 77042 | Oil & Gas Operator | Oct 1998 |
| 17 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 18 | Hunt, Hassie Exploration Company | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |