| 1 | Advanced Petro Corp | | Oil & Gas Operator | Dec 1992 |
| 2 | Airdale Oil & Gas LLC | Oil City, PA 16301-3771 | Oil & Gas Operator | Dec 2025 |
| 3 | Allegheny Enterprises Inc | Corsica, PA 15829-3833 | Oil & Gas Operator | Dec 2018 |
| 4 | Alliance Petroleum Corp | Canton, OH 44718-2553 | Oil & Gas Operator | Apr 2026 |
| 5 | Allshouse Terrence L Jr | Grand Valley, PA 16420-1930 | Oil & Gas Operator | Dec 2025 |
| 6 | Amer Natural Resources LLC | Rural Valley, PA 16249-0306 | Oil & Gas Operator | Dec 2018 |
| 7 | Anderson Energy SVC LLC | Clarendon, PA 16313-4238 | Oil & Gas Operator | Dec 2025 |
| 8 | Apex Resources Inc | Allison Park, PA 15101-3838 | Oil & Gas Operator | Dec 1993 |
| 9 | Ardent Resources, Inc. | Upper St Clair, PA 15241-1633 | Oil & Gas Operator | Dec 2018 |
| 10 | Atlas Resources Inc | Coraopolis, PA 15108-0611 | Oil & Gas Operator | Dec 2007 |
| 11 | Atlas Resources LLC | Pittsburgh, PA 15275-1033 | Oil & Gas Operator | Jun 2018 |