| 1 | H & O Operating Co | Odessa, TX 79764 | Oil & Gas Operator | Mar 2008 |
| 2 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 3 | Hanley Petroleum Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2017 |
| 4 | Hanson Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2008 |
| 5 | Hanvey, Don H. Oil Interests Inc | Cisco, TX 76437 | Oil & Gas Operator | Oct 2025 |
| 6 | Harkey Energy Inc. | Odessa, TX 79762 | Oil & Gas Operator | Feb 2020 |
| 7 | Harmony Drilling Company, Inc. | Denver, CO 80222 | Oil & Gas Operator | Nov 2016 |
| 8 | Hat Oil & Gas, Inc. | Slaton, TX 79364 | Oil & Gas Operator | Feb 2002 |
| 9 | Hawkeye Transmission Company | Dallas, TX 75244 | Oil & Gas Operator | Jun 2000 |
| 10 | Haylan Oil Company | Midland, TX 79710 | Oil & Gas Operator | Jan 2000 |
| 11 | Headington Energy Partners, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 12 | Headline Resources, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Aug 1997 |
| 13 | Heifer Production Company LLC | Houston, TX 77098 | Oil & Gas Operator | Oct 2025 |
| 14 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jun 2025 |
| 15 | Henderson & Erickson, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 16 | Hendrix, John H. Corporation | Midland, TX 79705 | Oil & Gas Operator | Sep 2018 |
| 17 | Henry Resources LLC | Midland, TX 79703 | Oil & Gas Operator | Oct 2025 |
| 18 | Hexagon Oil And Gas Inc. | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 19 | High Desert Resources, L.L.C. | Midland, TX 79704 | Oil Operator | Oct 2025 |
| 20 | Highland Production Company | Midland, TX 79701 | Oil & Gas Operator | Mar 1996 |
| 21 | Highpeak Energy Holdings, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 22 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 23 | Hillin Prod. Co. | Odessa, TX 79760 | Oil & Gas Operator | Apr 2002 |
| 24 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 25 | Hillside Oil & Gas, LLC | Midland, TX 79708 | Oil & Gas Operator | Apr 2016 |
| 26 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 27 | Home-Stake Oil & Gas Company | Plano, TX 75093 | Oil & Gas Operator | Jul 2025 |
| 28 | Hondo Drilling Company | Midland, TX 79702 | Oil & Gas Operator | Nov 1996 |
| 29 | Hopkins, T. M. Operating Co. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 30 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 31 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 32 | Hunter Oil & Gas Co. | Bangs, TX 76823 | Oil & Gas Operator | Oct 2025 |
| 33 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |