| 1 | S. Lavon Evans Jr., Operating Co., Inc. | | Oil & Gas Operator | Aug 2014 |
| 2 | Saga Petroleum Limited Liability Company Of Colorado | | Gas Operator | Dec 2014 |
| 3 | Saga Resource Management LLC | | Gas Operator | Dec 2025 |
| 4 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2025 |
| 5 | Sanford Resources Corp. | | Oil & Gas Operator | Jul 1998 |
| 6 | Shell Oil Co. | Houston, TX 77001 | Oil & Gas Operator | Jun 1985 |
| 7 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 8 | Signal, LLC | | Oil & Gas Operator | Dec 2025 |
| 9 | Skelton Operating Co., Inc. | | Oil & Gas Operator | Aug 1980 |
| 10 | Skelton, D.W. | | Oil Operator | Dec 1952 |
| 11 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Feb 2026 |
| 12 | Smackco, LTD. | | Oil & Gas Operator | Oct 2002 |
| 13 | Smackco, LTD./Bay City Minerals, Inc. | | Gas Operator | May 1990 |
| 14 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2026 |
| 15 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 16 | South Carlton Operating Company, LLC | | Oil Operator | Dec 2025 |
| 17 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 18 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 19 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 20 | Spooner Petroleum Company | | Oil & Gas Operator | Dec 2025 |
| 21 | Staghorn Resources, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2015 |
| 22 | Stetson Petroleum Corp. | Rollins, MT 59931 | Oil & Gas Operator | Feb 2026 |
| 23 | Strago Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Aug 1994 |
| 24 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Feb 2026 |
| 25 | Sunex Production, Inc. | | Gas Operator | Mar 1988 |
| 26 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 27 | Swift Energy Operating, LLC | Houston, TX 77079 | Oil & Gas Operator | Jun 2017 |