| 1 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 2 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2024 |
| 3 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 4 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 5 | Sandel Operating Company | Huntsville, TX 77340 | Oil & Gas Operator | Dec 2024 |
| 6 | Santa Fe Energy Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 7 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | Dec 2024 |
| 8 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 9 | Slaughter J M Oil Company | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2001 |
| 10 | Smith, L C Production | Jacksonville, TX 75766 | Oil Operator | Dec 2024 |
| 11 | Smith, L. C. | Jacksonville, TX 75766 | Oil & Gas Operator | Dec 2024 |
| 12 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 13 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 14 | Southwest Resources, Inc. | Brenham, TX 77834 | Oil & Gas Operator | Dec 2024 |
| 15 | Spri Oil & Gas, LLC | Houston, TX 77090 | Oil & Gas Operator | Mar 2020 |
| 16 | Stardust Leasing, Inc. | Richmond, TX 77469 | Oil & Gas Operator | Jul 1999 |
| 17 | Stasney, H. R. & Sons, LTD. | Albany, TX 76430 | Oil & Gas Operator | Dec 2024 |
| 18 | Stratlynn, Inc. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 19 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 20 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Dec 2024 |
| 21 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 22 | Sydri Operating, LLC | Dallas, TX 75231 | Oil & Gas Operator | Dec 2024 |