| 1 | H&G Petroleum Corporation | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 2 | Halliburton Operating Company | Plano, TX 75093 | Oil & Gas Operator | Oct 2025 |
| 3 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 4 | Hanley Petroleum Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 5 | Hannathon Petroleum, LLC | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 6 | Hanson Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2008 |
| 7 | Harvard Petroleum Corporation | Roswell, NM 88201 | Oil & Gas Operator | Dec 2004 |
| 8 | Harvest Petroleum Inc. | Frisco, TX 75033 | Oil & Gas Operator | Oct 2025 |
| 9 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 10 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 11 | Helms Oil & Gas, LLC | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 12 | Henderson Natural Res, L.L.C. | Crozet, VA 22932 | Oil & Gas Operator | Oct 2025 |
| 13 | Henderson, Peter Oil Co. | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2020 |
| 14 | Hendrix, John H. Corporation | Midland, TX 79705 | Oil & Gas Operator | Sep 2018 |
| 15 | Henry Petroleum LLC | Flower Mound, TX 75028 | Oil & Gas Operator | Oct 2025 |
| 16 | Henson Exploration, L.P. | Abilene, TX 79608 | Oil & Gas Operator | Oct 2025 |
| 17 | HGN Operating Co. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2014 |
| 18 | HGN Operating I, LLC | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 19 | Hickox Oil Texas Company, Inc. | Mobile, AL 36689 | Oil & Gas Operator | Feb 1996 |
| 20 | Highmount Expl & Prod Texas LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2014 |
| 21 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 22 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 23 | Huff, Jack | Midland, TX 79710 | Oil & Gas Operator | Dec 2004 |
| 24 | Huffman, H. L., LTD. | Fort Worth, TX 76113 | Oil & Gas Operator | Sep 1994 |
| 25 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 26 | Hurst Oil & Gas, Inc. | Hillsboro, TX 76645 | Oil & Gas Operator | Dec 2024 |
| 27 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |
| 28 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |