| 1 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 2 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2024 |
| 3 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 4 | Santa Fe Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 5 | Santana Exploration, Inc. | | Oil & Gas Operator | Dec 1985 |
| 6 | Scana Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Dec 1999 |
| 7 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 8 | Sceptre Resources Inc | | Oil & Gas Operator | Dec 2007 |
| 9 | Schmid Properties Inc | Hico, TX 76457 | Oil & Gas Operator | Nov 2024 |
| 10 | Sevarg Company, Inc. | | Oil & Gas Operator | Feb 2016 |
| 11 | Shelf Energy, LLC | | Oil & Gas Operator | Jun 2024 |
| 12 | Shenandoah Oil Corporation | | Oil & Gas Operator | Jun 1979 |
| 13 | Silver Oak Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 2009 |
| 14 | Silver Oak Operating, LLC | Longview, TX 75604 | Oil & Gas Operator | Nov 2024 |
| 15 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 16 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Nov 2024 |
| 17 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 18 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Nov 2024 |
| 19 | South La. Production Co., Inc. | | Oil & Gas Operator | Jun 1982 |
| 20 | Southern G Holdings, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2007 |
| 21 | Southern Production & Expl Co. | | Oil & Gas Operator | Apr 2008 |
| 22 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 23 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 24 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 25 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 26 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |