| 1 | Earthstone Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2017 |
| 2 | Eclipse Services, Inc. * | La Grange, TX 78945 | Oil & Gas Operator | Jul 2003 |
| 3 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 4 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 5 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 6 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 7 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 8 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 9 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 10 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Oct 2025 |
| 11 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 12 | Encino Exploration, Inc. | George West, TX 78022 | Oil & Gas Operator | Oct 2025 |
| 13 | Endeavor Production Company | San Angelo, TX 76904 | Oil & Gas Operator | Mar 2008 |
| 14 | Energen Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Jan 2021 |
| 15 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 16 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 17 | Ernest Operating Company | Rockdale, TX 76567 | Oil & Gas Operator | Oct 2025 |
| 18 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 19 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 20 | Etoco, L.P. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 21 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 22 | Excalibur E & P, LLC | Johnson City, TX 78636 | Oil & Gas Operator | Oct 2025 |
| 23 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2025 |
| 24 | Expro Engineering, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Oct 2025 |
| 25 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 26 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |