This is a list of companies that can be found in Team Fortress 2. Most of these are presumed to be sub-fronts for the intelligence agencies behind Reliable Excavation Demolition and Builders League United.
"Properties" are the maps that the company possesses buildings on. "Team tendency" is the team that the company tends to lean towards in building style. Some companies have no properties, but appear on advertisement posters in-game or in promotional materials.