| 1 | H & H Star Energy Inc | Traverse City, MI 49684 | Oil & Gas Operator | Aug 2016 |
| 2 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 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 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 6 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Oct 2025 |
| 7 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Jun 2025 |
| 8 | Harrell Verlan W | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Nov 1999 |
| 9 | Harris Minerals Corp (The) | Oklahoma City, OK 73162-1045 | Oil & Gas Operator | Jun 2025 |
| 10 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 11 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 12 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 13 | Hep Oil Company LTD | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 14 | Hep Oil GP, LLC | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 15 | Hess Corporation | Houston, TX 77010 | Oil & Gas Operator | Aug 2017 |
| 16 | High Sierra Water Services Mid Continent LLC | Denver, CO 80209 | Oil Operator | Feb 2010 |
| 17 | Highland Oil & Gas LLC | Houston, TX 77079-7220 | Oil & Gas Operator | Feb 2015 |
| 18 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 19 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 20 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 21 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Jul 2025 |
| 22 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 23 | Home-Stake Royalty Corp., The | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2014 |
| 24 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 25 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 26 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 27 | Horizon Oil & Gas Co. | Dallas, TX 75221 | Oil & Gas Operator | Jan 2005 |
| 28 | Hull Oil Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Sep 2021 |
| 29 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 30 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 31 | Hunt, H L | Dallas, TX 75202-2785 | Oil & Gas Operator | Dec 2024 |
| 32 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |