| 1 | Sable Minerals, Inc. | | Oil & Gas Operator | Nov 1993 |
| 2 | Saline Injection Systems Co. | | Oil Operator | Jan 2025 |
| 3 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 4 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | Aug 2025 |
| 5 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 6 | Sandefer Petroleum Co. | | Oil & Gas Operator | Apr 1994 |
| 7 | Sante Fe Minerals | | Oil & Gas Operator | Dec 1987 |
| 8 | Scurlock Oil Co | | Oil Operator | May 1982 |
| 9 | Se USA Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 10 | Seaboard Pipe & Equip. Co. | | Oil & Gas Operator | May 1977 |
| 11 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 12 | Seal Energy Company | | Oil Operator | Dec 2024 |
| 13 | Sealexco | | Oil & Gas Operator | Jun 1992 |
| 14 | Secondary Recovery, Inc. | | Oil & Gas Operator | Dec 1991 |
| 15 | Sevarg Company, Inc. | | Oil & Gas Operator | Feb 2016 |
| 16 | Shale Energy International, LLC | | Oil & Gas Operator | Nov 2024 |
| 17 | Shelf Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 18 | Shenandoah Oil Corporation | | Oil & Gas Operator | Jun 1979 |
| 19 | Simar Petroleum, LLC | | Oil Operator | Dec 2024 |
| 20 | Simco Oil Company | | Oil Operator | Jul 1990 |
| 21 | Sitwell, Inc. | | Oil Operator | May 2022 |
| 22 | Solatex Resources, LTD | Houston, TX 77257 | Oil & Gas Operator | Oct 2025 |
| 23 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 24 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Oct 2025 |
| 25 | South La. Production Co., Inc. | | Oil & Gas Operator | Jun 1982 |
| 26 | Southern Production & Expl Co. | | Oil & Gas Operator | Apr 2008 |
| 27 | Southwest Gas Producing Co Inc | | Oil & Gas Operator | Nov 1994 |
| 28 | Southwest Oil Properties, Inc. | | Oil & Gas Operator | Feb 1996 |
| 29 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 30 | Speco Oil Company | | Oil & Gas Operator | Feb 1980 |
| 31 | Square Mile Energy, L.L.C. | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 32 | SRP Production Corp. | | Oil & Gas Operator | Nov 1997 |
| 33 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 34 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 35 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 36 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 37 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 38 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 39 | Sunchase Exploration, Inc. | | Oil & Gas Operator | Oct 1997 |
| 40 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 41 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 42 | Synergy Oil & Gas, L.P. | Houston, TX 77024 | Oil & Gas Operator | May 2012 |