| 1 | Sabco Operating Company | Houston, TX 77056 | Oil & Gas Operator | Oct 2011 |
| 2 | Sabco Operating Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jun 2018 |
| 3 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 4 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 5 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 6 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 7 | Scoggins Oil & Gas Co. | Seabrook, TX 77586 | Oil & Gas Operator | Jun 2000 |
| 8 | Seneca Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 9 | Sentry Exploration, Inc. | Houston, TX 77006 | Oil & Gas Operator | Oct 2025 |
| 10 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 11 | Sierra Minerals, Inc. | Rockdale, TX 76567 | Oil & Gas Operator | Oct 2025 |
| 12 | Silverbrook Operating II LLC | Barker, TX 77413 | Oil & Gas Operator | Oct 2025 |
| 13 | Silverbrook Operating, LLC | Barker, TX 77413 | Oil Operator | Oct 2025 |
| 14 | Sonterra Operating, Inc. | Houston, TX 77060 | Oil & Gas Operator | Oct 2025 |
| 15 | South Bay Resources, L.L.C. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 16 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 17 | Southwest Oil & Land, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 1999 |
| 18 | St. Mary Energy Company | Houston, TX 77079 | Oil & Gas Operator | Aug 2008 |
| 19 | Stanotex, LLC | Katy, TX 77494 | Oil & Gas Operator | Oct 2025 |
| 20 | Sterling Expl. & Prod. Co., LLC | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 21 | Strago Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Aug 1994 |
| 22 | Stroud Production LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 23 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |
| 24 | Sure Flow Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Mar 2008 |
| 25 | Sutton Producing Corp. | San Antonio, TX 78270 | Oil & Gas Operator | Oct 2025 |
| 26 | Synergy Oil & Gas, Inc. (A) | Houston, TX 77024 | Oil & Gas Operator | Aug 2001 |
| 27 | Synergy Production Company | Houston, TX 77024 | Oil & Gas Operator | Jan 1996 |