| 1 | H-W Operating Company | Oklahoma City, OK 73112 | Gas Operator | Nov 1998 |
| 2 | H.L.S. Energy Co., Inc. | Uvalde, TX 78801 | Oil & Gas Operator | Aug 2003 |
| 3 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 4 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 5 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Oct 2025 |
| 6 | Hallum Construction Inc | Seminole, OK 74868-2427 | Oil & Gas Operator | Sep 2014 |
| 7 | Harbert Energy Corp | Irving, TX 75015-2510 | Oil & Gas Operator | Feb 1993 |
| 8 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Nov 2025 |
| 9 | Harding And Shelton Exploration LLC | Oklahoma City, OK 73101-1557 | Oil & Gas Operator | Nov 2025 |
| 10 | Hargus Irrevocable Trust | Tecumseh, OK 74873-0590 | Oil Operator | Apr 2014 |
| 11 | Henry Petroleum Inc | Oklahoma City, OK 73162-1757 | Oil & Gas Operator | Sep 2019 |
| 12 | Hilliard Oil & Gas, Inc. | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 13 | Himco Oil & Gas Inc | Enid, OK 73702 | Oil & Gas Operator | Nov 2025 |
| 14 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 15 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Dec 2025 |
| 16 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 17 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Nov 2025 |
| 18 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 19 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 20 | Hovas Enterprises | Perkins, OK 74059 | Oil & Gas Operator | Mar 2014 |
| 21 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Feb 2026 |
| 22 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Feb 2026 |
| 23 | Hughes Gas Systems LLC | Oklahoma City, OK 73118-4821 | Oil & Gas Operator | Nov 2025 |
| 24 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |