| 1 | H & L Operating Co., L.L.P. | Amarillo, TX 79114 | Oil & Gas Operator | Aug 2022 |
| 2 | H & L Operating Company | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2020 |
| 3 | H2ox Operating LLC | Tulsa, OK 74103 | Oil Operator | Oct 2025 |
| 4 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Oct 2025 |
| 5 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 6 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 7 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 8 | Harris Oil & Gas Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2016 |
| 9 | Harrison-Wright Oil Company LLC | Tulsa, OK 74133-7035 | Oil & Gas Operator | Dec 2025 |
| 10 | Hartman Oil Company Inc | Wichita, KS 67206 | Oil & Gas Operator | Sep 2025 |
| 11 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 12 | HCM Resources LLC | Guymon, OK 73942 | Gas Operator | Mar 2015 |
| 13 | Heat Waves Hot Oil Service LLC | Denver, CO 80202 | Oil Operator | Jun 2011 |
| 14 | Highmark Energy Operating LLC | Dallas, TX 75222 | Oil & Gas Operator | Feb 2026 |
| 15 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 16 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Dec 2025 |
| 17 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 18 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 19 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 20 | Horizon Oil & Gas Co. | Dallas, TX 75221 | Oil & Gas Operator | Jan 2005 |
| 21 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 22 | Hunt Chris Water Hauling Contractor Inc | Keyes, OK 73947-0004 | Oil Operator | Jun 2008 |
| 23 | Hunt Engineering Inc | Norman, OK 73069-4093 | Oil & Gas Operator | Feb 2019 |
| 24 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |
| 25 | Hyperion Energy LP | Dallas, TX 75206 | Oil & Gas Operator | May 2014 |