| 1 | H & M Petroleum Corporation | Lincoln, NE 68516 | Oil & Gas Operator | May 2025 |
| 2 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 3 | Halde Oil Inc | | Oil & Gas Operator | Jun 2025 |
| 4 | Haley/Hughes Operations | | Oil Operator | Apr 2001 |
| 5 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 2025 |
| 6 | Harsh International Inc | | Oil & Gas Operator | Dec 2013 |
| 7 | Hathaway Operators, Inc | | Oil & Gas Operator | Dec 2000 |
| 8 | Hayes Oil & Gas Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2005 |
| 9 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 10 | Heartland Oil & Gas Company | | Oil & Gas Operator | Jun 2000 |
| 11 | Hec Petroleum, Inc | Midland, TX 79705 | Oil & Gas Operator | Mar 2006 |
| 12 | Helena Resources Inc | Lakewood, CO 80215 | Oil & Gas Operator | Jun 2025 |
| 13 | High Plains Energy LLC | | Oil & Gas Operator | May 2017 |
| 14 | High River Resources Operating LLC | Farmington, NM 87401 | Oil & Gas Operator | May 2025 |
| 15 | Highpoint Energy LLC | | Oil & Gas Operator | Nov 2022 |
| 16 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2025 |
| 17 | Holcomb Oil & Gas Inc | Farmington, NM 87401 | Oil & Gas Operator | Jun 2025 |
| 18 | Homestead Oil Inc | | Oil & Gas Operator | Jan 2018 |
| 19 | Horseshoe Operating Inc | Midland, TX 79701 | Oil & Gas Operator | Jan 2023 |
| 20 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 21 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 22 | HRC Operating, LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2017 |
| 23 | HRM Resources II, LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 24 | HRM Resources III LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2022 |
| 25 | HRM Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2015 |
| 26 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 27 | Hubbard Creek Coal Gas LLC | | Gas Operator | Jun 2025 |
| 28 | Hubbs III, LLC | | Oil & Gas Operator | Mar 2024 |
| 29 | Huber Corporation* J M | | Oil & Gas Operator | Feb 2008 |
| 30 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 31 | Hyndrex Resources | | Oil & Gas Operator | Apr 2018 |