| 1 | H G & G Inc | Edmond, OK 73034 | Oil & Gas Operator | Jan 2006 |
| 2 | H2ox Operating LLC | Tulsa, OK 74103 | Oil Operator | Jul 2025 |
| 3 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Jun 2025 |
| 4 | Halcyon Natural Gas LLC | Oklahoma City, OK 73116-9111 | Oil & Gas Operator | Jun 2025 |
| 5 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 6 | Hamil Oil & Gas LLC | Kingfisher, OK 73750-6500 | Oil & Gas Operator | Jul 2025 |
| 7 | Harding And Shelton Exploration LLC | Oklahoma City, OK 73101-1557 | Oil & Gas Operator | Jun 2025 |
| 8 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 9 | Harrell Petroleum Inc | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Oct 2017 |
| 10 | Harrell Verlan W | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Nov 1999 |
| 11 | Hartman Oil Co., Inc. | Wichita, KS 67206 | Oil & Gas Operator | Jun 2025 |
| 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 | Heartland Exploration Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2015 |
| 15 | Heath Oil Co., Inc. | Washington, OK 73093-4702 | Oil & Gas Operator | Jun 2025 |
| 16 | Helke Exploration Company | Oklahoma City, OK 73112-7201 | Oil & Gas Operator | Feb 2000 |
| 17 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 18 | Henry Gungoll Operating Inc | Enid, OK 73703 | Oil & Gas Operator | Jul 2025 |
| 19 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Oct 2025 |
| 20 | Hess Corporation | Houston, TX 77010 | Oil & Gas Operator | Aug 2017 |
| 21 | Hexagon Oil And Gas Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 22 | Hibbert R E Estate Of | Houston, TX 77002-3211 | Oil & Gas Operator | Apr 2015 |
| 23 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 24 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Jul 2025 |
| 25 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Jun 2025 |
| 26 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 27 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 28 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 29 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Oct 2025 |
| 30 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 31 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 32 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 33 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |