| 1 | H & O Operating Co | Odessa, TX 79764 | Oil & Gas Operator | Mar 2008 |
| 2 | Hadaway Consult And Engineer,LLC | Canadian, TX 79014 | Oil & Gas Operator | Oct 2025 |
| 3 | Hallwood Energy Corporation | Oklahoma City, OK 73154 | Oil & Gas Operator | Feb 2005 |
| 4 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 5 | Halvey Energy Co. | Midland, TX 79702 | Oil & Gas Operator | Oct 2004 |
| 6 | Halvey Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 7 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 8 | Hamon Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2011 |
| 9 | Hanley Petroleum Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 10 | Hanna Oil And Gas Company | Fort Smith, AR 72901 | Oil & Gas Operator | Jun 2025 |
| 11 | Hannathon Petroleum, LLC | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 12 | Hanson Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2008 |
| 13 | Harvard Petroleum Corporation | Roswell, NM 88201 | Oil & Gas Operator | Dec 2004 |
| 14 | HCM | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 15 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 16 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 17 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 18 | Heights Energy Corporation | Plano, TX 75026 | Oil & Gas Operator | Oct 2025 |
| 19 | Henry Petroleum Corp. | Midland, TX 79703 | Oil & Gas Operator | Mar 2001 |
| 20 | Henry Petroleum LP | Midland, TX 79701 | Oil & Gas Operator | Dec 2008 |
| 21 | HGN Operating Co. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2014 |
| 22 | HGN Operating I, LLC | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 23 | Hi - Mountain Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Oct 2025 |
| 24 | Hibernia Resources IV, LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 25 | High Mountain Oil & Gas | Hobbs, NM 88240 | Oil & Gas Operator | Jan 2019 |
| 26 | High Mountain Oil & Gas, LLC | Hobbs, NM 88240 | Oil & Gas Operator | Oct 2025 |
| 27 | Hillin Simon/Prime Expl., L.C. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 28 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 29 | Holly Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 2008 |
| 30 | Honeck Oil Company | Austin, TX 78716 | Oil & Gas Operator | Mar 2008 |
| 31 | Honeck Oil Company, LP | Austin, TX 78716 | Oil & Gas Operator | Dec 2010 |
| 32 | Hopkins, T. M. Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 33 | HPC Operating, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Mar 2008 |
| 34 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 35 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 36 | HW Operating, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |