| 1 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 2 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Jun 2025 |
| 3 | Harbert Energy Corp | Irving, TX 75015-2510 | Oil & Gas Operator | Feb 1993 |
| 4 | Harris Oil & Gas Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2016 |
| 5 | Harrod Leasing | Edmond, OK 73034 | Oil & Gas Operator | Jun 2025 |
| 6 | Hatley Delbert Jr Dba DH Enterprises | Oklahoma City, OK 73129 | Oil & Gas Operator | Jun 2025 |
| 7 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Jun 2025 |
| 8 | HCM | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 9 | Heartland Exploration Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2015 |
| 10 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 11 | Hexagon Oil And Gas Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 12 | High Energy | Cushing, OK 74023 | Oil & Gas Operator | May 2025 |
| 13 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 14 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 15 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Jul 2025 |
| 16 | Hoke Jr J T | Edmond, OK 73034 | Oil Operator | Nov 1998 |
| 17 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 18 | Hollrah Exploration Company | Edmond, OK 73012 | Oil & Gas Operator | Jun 2025 |
| 19 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 20 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 21 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 22 | Hsumy Oil & Gas Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2007 |
| 23 | Huck Farms LLC | Stratford, OK 74872 | Oil & Gas Operator | Jun 2025 |
| 24 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 25 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 26 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |
| 27 | Hunton Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 28 | Hurley Charles B | Santa Ana, CA 92706 | Oil & Gas Operator | Apr 2015 |