| 1 | H & L Exploration Company, LLC | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2026 |
| 2 | H & L Operating Co., L.L.P. | Amarillo, TX 79114 | Oil & Gas Operator | Aug 2022 |
| 3 | H & L Operating Co., LLC | Amarillo, TX 79114 | Oil & Gas Operator | Mar 2021 |
| 4 | H & L Operating Company | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2020 |
| 5 | H-S Exploration | Gunnison, CO 81230 | Oil & Gas Operator | Feb 2026 |
| 6 | Hadaway Consult And Engineer,LLC | Canadian, TX 79014 | Oil & Gas Operator | Feb 2026 |
| 7 | Hadaway Engineering Inc | Canadian, TX 79014 | Oil & Gas Operator | Jul 2015 |
| 8 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 9 | Hanshu Production Company | Darrouzett, TX 79024 | Oil & Gas Operator | Apr 2017 |
| 10 | Hanshu Production Company, LLC | Nashville, TN 37215 | Gas Operator | Feb 2026 |
| 11 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 12 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 13 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 14 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 15 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Nov 2025 |
| 16 | Hep Oil Company, LTD. | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 17 | High River Res Operating, LLC | Dallas, TX 75219 | Oil & Gas Operator | Feb 2026 |
| 18 | Highmark Energy Operating LLC | Dallas, TX 75222 | Oil & Gas Operator | Feb 2026 |
| 19 | Highmount Operating LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2014 |
| 20 | Holco Oil & Gas | Borger, TX 79008 | Oil & Gas Operator | Feb 2026 |
| 21 | Holmes Exploration, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2015 |
| 22 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Feb 2026 |
| 23 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 24 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 25 | Horizon Oil & Gas Co. | Dallas, TX 75221 | Oil & Gas Operator | Jan 2005 |
| 26 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2002 |
| 27 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Feb 2026 |
| 28 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 29 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |