| 1 | Sandel Energy, Inc. | Huntsville, TX 77342 | Oil & Gas Operator | Apr 2004 |
| 2 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Dec 2025 |
| 3 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Dec 2025 |
| 4 | Sem Operating Company LLC | Houston, TX 77042 | Oil & Gas Operator | Dec 2025 |
| 5 | Seneca Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 6 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 7 | Sharon Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Aug 2010 |
| 8 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Dec 2025 |
| 9 | Sikes Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2003 |
| 10 | Silver Creek Oil & Gas, LLC | Flower Mound, TX 75022 | Oil & Gas Operator | Dec 2025 |
| 11 | Silver Creek Resources, LLC | Irving, TX 75038 | Oil & Gas Operator | Apr 2017 |
| 12 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 13 | Smith, L. C. | Jacksonville, TX 75766 | Oil & Gas Operator | Dec 2025 |
| 14 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 15 | Sonat Exploration Company -Tyler | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 16 | South Oil, Inc. | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 17 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 18 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 19 | Southwest Gas Systems, Inc. | Spring, TX 77379 | Oil & Gas Operator | Dec 2025 |
| 20 | Southwest Resources, Inc. | Brenham, TX 77834 | Oil & Gas Operator | Dec 2025 |
| 21 | Square One Corporation | Giddings, TX 78942 | Oil & Gas Operator | Dec 2012 |
| 22 | Stanton Mineral Development Inc | Austin, TX 78759 | Oil & Gas Operator | Dec 2025 |
| 23 | Stoneham Oil Company | Houston, TX 77002 | Oil & Gas Operator | Sep 1995 |
| 24 | Strago Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Aug 1994 |
| 25 | Stratlynn, Inc. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 26 | Stroud Energy, LTD. | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2006 |
| 27 | Stroud Oil Properties, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | May 2013 |
| 28 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Dec 2025 |
| 29 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |