| 1 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 2 | Hamon Oil Company | | Oil & Gas Operator | Aug 1985 |
| 3 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 4 | Harvest Oil & Gas, LLC | | Oil & Gas Operator | Feb 2012 |
| 5 | Hassie Hunt Expl. Company | | Oil & Gas Operator | Aug 2008 |
| 6 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 7 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 8 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 9 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 10 | Hemco Development, LLC | Dallas, TX 75201 | Oil & Gas Operator | Nov 2020 |
| 11 | Henry Production Company, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Oct 2019 |
| 12 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 13 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 14 | Hilliard Petroleum Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2009 |
| 15 | Hogan Energy Corporation | | Oil & Gas Operator | Oct 1999 |
| 16 | Houston Energy Operating, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jul 2020 |
| 17 | Houston Energy, L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 18 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 19 | Houston Oil Fields Company | | Oil & Gas Operator | Apr 1987 |
| 20 | Huffco Petroleum Corporation | | Oil & Gas Operator | Jul 1988 |
| 21 | Hugh A. Hawthorne, Et Al | | Oil & Gas Operator | Dec 1978 |
| 22 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 23 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 24 | Hunter Oil & Gas, LLC | | Oil & Gas Operator | Oct 2001 |