| 1 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 2 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 3 | Seneca Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 4 | Shell Offshore Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 2008 |
| 5 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 6 | Shenandoah Oil Corporation | | Oil & Gas Operator | Jun 1979 |
| 7 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 8 | Shoreline Offshore LLC | | Oil & Gas Operator | Jun 2017 |
| 9 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 10 | Skelly Oil Co | | Oil & Gas Operator | Mar 2005 |
| 11 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 12 | Soldier Operating LLC | | Oil & Gas Operator | Dec 2024 |
| 13 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 14 | Sonat Exploration Gom Inc. | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 15 | South Oak Production Company | | Oil & Gas Operator | Jun 2010 |
| 16 | Southern Natural Gas Co | Houston, TX 77001 | Oil & Gas Operator | Dec 2011 |
| 17 | Southern Natural Gas Company LLC | | Oil & Gas Operator | Nov 2024 |
| 18 | Spooner Petroleum Company | | Oil & Gas Operator | Jul 2025 |
| 19 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 20 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 21 | Strata Energy, Inc. | | Oil & Gas Operator | Sep 1983 |
| 22 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 23 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |
| 24 | Sugar Bowl Gas Corp. | | Oil Operator | Dec 1983 |
| 25 | Summit Energy Company | | Oil & Gas Operator | Mar 2009 |
| 26 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 27 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 28 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 29 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |