| Ameresco Palmetto | Owner/operator | Framingham, MA | | |
| Ameresco Pine Bluff, LLC | Owner/operator | Framingham, MA | | |
| Ameresco San Antonio LLC | Owner/operator | Framingham, MA | | 1 |
| Ameresco Woodland Meadows Romulus LLC | Owner/operator | Framingham, MA | | |
| American Cap Company, LLC | Pipe mill | | | |
| American Central Gas Technologies Inc | Owner/operator | | | |
| American Coastal Energy Inc | Owner/operator | | | |
| American Energies Gas Service, LLC | Owner/operator | Canton, KS | | 1 |
| American Energies Pipeline, LLC | Owner/operator | Canton, KS | | 1 |
| American Gypsum Co LLC | Owner/operator | | | 1 |
| American Hydrovac | Contractor | | 1 | |
| American Midstr Offsh (seacr) LP | Owner/operator | | | 5 |
| American Midstream | Owner/operator | | 1 | 3 |
| American Midstream (Midla), LLC | Owner/operator | | 1 | |
| American Midstream (alabama Gathering) LLC | Owner/operator | Denver, CO | | 1 |
| American Midstream (alabama Intrastate) LLC | Owner/operator | | | |
| American Midstream (alatenn), LLC | Owner/operator | | 1 | |
| American Midstream (bamagas Intrastate) LLC | Owner/operator | | | |
| American Midstream (louisiana Intrastate), LLC | Owner/operator | | 4 | |
| American Midstream (mississippi), LLC | Owner/operator | Houston, TX | | 1 |
| American Midstream (seacrest), LP | Owner/operator | Houston, TX | | 1 |
| American Midstream (sigco Intrastate), LLC | Owner/operator | | | |
| American Midstream (tennessee River) LLC | Owner/operator | | | |
| American Midstream Bakken, LLC | Owner/operator | Houston, TX | | 1 |
| American Midstream C/o Jacobs Engineering | Owner/operator | | 1 | |
| American Midstream Chatom, LLC | Owner/operator | | | 1 |
| American Midstream Gas Solutions, LP | Owner/operator | | | |
| American Midstream Onshore Pipelines, LLC | Owner/operator | | | |
| American Midstream Permian, LLC | Owner/operator | | | |
| American Municipal Power Amp | Owner/operator | Columbus, OH | | 1 |
| American Natural Energy Corp. | Owner/operator | | 2 | |
| American Panther, LLC | Owner/operator | | 1 | |
| American Pipeline Inspection, LLC | Third-party inspection | Louisburg, KS | | |
| American Piping Inspection | NDT | | | |
| American River Transp CO | Owner/operator | | | 1 |
| American Steel Pipe | Pipe mill | | 1 | |
| American Steel Pipe Birmingham | Pipe mill | | | |
| American Water MSG | Owner/operator | | | 1 |
| Americo Energy Resources LLC | Owner/operator | Houston, TX | | 4 |
| Amerigas | Owner/operator | | | |
| Amerigas Propane | Owner/operator | | | 1 |
| Amid Silver Dollar Pipeline LLC | Owner/operator | Houston, TX | | 1 |
| Amoco Exploration And Producing | Owner/operator | | | |
| Amoco Oil Co | Owner/operator | Chicago, IL | | 1 |
| Amoco Production Company | Owner/operator | | | |
| Amoco Producton Company | Owner/operator | | 2 | |
| Amp Angelina, LLC | Owner/operator | Dallas, TX | | 8 |
| Amp Etx Gathering, LLC | Owner/operator | Dallas, TX | | 2 |
| Amp Gathering I, LP | Owner/operator | Dallas, TX | | 1 |
| Amp II Etx Gathering I, LLC | Owner/operator | | | 11 |