| 1 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 2 | S & S Oil Company | Electra, TX 76360 | Oil & Gas Operator | Oct 2025 |
| 3 | S&B Petroleum Corporation | | Oil & Gas Operator | Jun 1994 |
| 4 | S2 Energy Operating LLC | | Oil & Gas Operator | May 2023 |
| 5 | Sackett Oil Company | | Oil & Gas Operator | Oct 1995 |
| 6 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 7 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 8 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | Aug 2025 |
| 9 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 10 | Sandpoint Energy Partners LLC | | Oil Operator | Jan 2025 |
| 11 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Oct 2025 |
| 12 | Secondary Recovery, Inc. | | Oil & Gas Operator | Dec 1991 |
| 13 | Semo, Inc. | | Oil & Gas Operator | Feb 2002 |
| 14 | Senior Drilling & Expl Co Inc. | | Oil & Gas Operator | Apr 1993 |
| 15 | Setex Oil And Gas Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2012 |
| 16 | Shelf Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 17 | Shell Oil Company | Houston, TX 77210 | Oil & Gas Operator | Apr 2015 |
| 18 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 19 | Shocker Energy, Inc. | | Oil & Gas Operator | Oct 1992 |
| 20 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 21 | Sierra Production Company | | Oil & Gas Operator | May 1986 |
| 22 | Singer Fleischaker Oil Op. Co. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2002 |
| 23 | Singer-Fleischaker,Dillon | | Oil & Gas Operator | Aug 1979 |
| 24 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 25 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 26 | Sohio Petroleum Co. | Casper, WY 82602 | Oil & Gas Operator | Apr 1986 |
| 27 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | Oct 2025 |
| 28 | Southern G Holdings, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2007 |
| 29 | Southern Operating, Inc. | | Oil Operator | Dec 2000 |
| 30 | Spartan Petroleum Corporation | Houston, TX 77079 | Oil & Gas Operator | Oct 1987 |
| 31 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 32 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 33 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 34 | Subsurface Resources Inc | Logan, UT 84321 | Oil & Gas Operator | Aug 1990 |
| 35 | Summit Energy, Inc. | Littleton, CO 80127 | Oil & Gas Operator | Aug 2013 |
| 36 | Sun Exploration-Production Co. | | Oil & Gas Operator | Jan 1990 |
| 37 | Sun Texas Company | | Oil & Gas Operator | Jun 1981 |
| 38 | Sunland Production Company, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2025 |
| 39 | Superior Oil Co. | Denver, CO 80217-5444 | Oil & Gas Operator | Feb 2001 |
| 40 | Sutton Joint Account | | Oil Operator | Mar 1988 |
| 41 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 42 | Synergy Oil & Gas, Inc. | Houston, TX 77024 | Oil & Gas Operator | Nov 2019 |