| 1 | Amer Natural Resources LLC | Rural Valley, PA 16249-0306 | Oil & Gas Operator | Dec 2018 |
| 2 | Ams Energy LLC | Herman, PA 16039-0156 | Oil & Gas Operator | Jul 2025 |
| 3 | Anegada Energy LLC | Canonsburg, PA 15317-0400 | Gas Operator | Jul 2025 |
| 4 | Apollo Gas Co | Pittsburgh, PA 15236-1435 | Gas Operator | Dec 1991 |
| 5 | Apollo Resources LLC | Vintondale, PA 15961-0222 | Oil & Gas Operator | Jul 2025 |
| 6 | Armstrong Gas Co LLC | Kittanning, PA 16201-2269 | Oil & Gas Operator | Dec 2018 |
| 7 | Atlas Resources Inc | Coraopolis, PA 15108-0611 | Oil & Gas Operator | Dec 2007 |
| 8 | Atlas Resources LLC | Pittsburgh, PA 15275-1033 | Oil & Gas Operator | Jun 2018 |