| 1 | H2ox Operating LLC | | Oil Operator | Jan 2024 |
| 2 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Nov 2018 |
| 3 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 4 | Ham Oil Company, LLC | | Oil Operator | Sep 2022 |
| 5 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Apr 2024 |
| 6 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 7 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 8 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 9 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 10 | High Sierra Crude Oil& Marketing LLC | Ardmore, OK 73401 | Oil Operator | Nov 2013 |
| 11 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 12 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Dec 2023 |
| 13 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Jan 2024 |
| 14 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 15 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 16 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Dec 2023 |
| 17 | Huitt Joe A | Tulsa, OK 74103 | Oil & Gas Operator | May 2001 |
| 18 | Hulen Operating Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2024 |
| 19 | Hy-Carb Energy Inc | | Oil & Gas Operator | Feb 2009 |