| 1 | S.B. Oil Company, A General Partnership | Hays, KS 67601 | Oil Operator | Sep 2019 |
| 2 | Samson Resources | | Oil Operator | Jan 1994 |
| 3 | Sandlin Oil Corp | Dacono, CO 80514 | Oil & Gas Operator | Aug 2025 |
| 4 | Satchell Creek Petroleum, LLC | Wichita, KS 67205 | Oil Operator | Jul 2024 |
| 5 | Scheck Oil Operation | | Oil & Gas Operator | Jun 2025 |
| 6 | Schlobohm, Starr F. | Wolfeboro, NH 03894 | Oil Operator | Jul 2004 |
| 7 | Sentinel Petroleum Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2020 |
| 8 | Shelby Resources LLC | Denver, CO 80207 | Oil & Gas Operator | Jun 2025 |
| 9 | Shields Oil Producers Inc. | Russell, KS 67665 | Oil Operator | Jun 2025 |
| 10 | Slawson, Donald C. | Wichita, KS 67202 | Oil & Gas Operator | Apr 2025 |
| 11 | Smoky Valley Res | | Oil & Gas Operator | Dec 1995 |
| 12 | Southern States | | Oil & Gas Operator | Jul 1988 |
| 13 | Spiral Energy Corp. | Midland, TX 79705 | Oil & Gas Operator | Dec 2019 |
| 14 | Spring, Harry A. | Ardmore, OK 73401 | Oil Operator | Jul 2012 |
| 15 | Staab Oil Co., A General Partnership | Hays, KS 67601 | Oil Operator | Jun 2025 |
| 16 | Standard Operating Company | Wichita, KS 67205 | Oil & Gas Operator | Jun 2025 |
| 17 | Stratakan Exploration, LLC | Plainville, KS 67663 | Oil & Gas Operator | Jun 2025 |
| 18 | Stull Oil LLC | Natoma, KS 67651 | Oil Operator | Jun 2025 |
| 19 | Sunoco Partners Marketing | | Oil Operator | Apr 2023 |