The following is a list of mentioned organizations in the Alien Swarm universe which miss too much information to justify their own articles.
The Core Systems are the oldest, most powerful, and important worlds in the Interstellar Alliance, they are the founding worlds. Earth, birthplace of the human race and Mars, the first world colonized by the human race, both located in the Sol system.
The Humanist Protectorate are a pro-human hate group.
Spacefarer Inc. is a megacorporation that manufactures Starships. Their long-distance passenger ship the 'Titanic' fell victim to a vicious Swarm attack, despite their best attempts to build an "impenetrable" sleeper ship. Passengers on Spacefarer Inc. ships are traditionally placed in hypersleep.
The Starbase Systems corporation makes the stock trading database software used by the Trade Leagues.
The Chosen are a pro-human hate group.
It appears that the Trade Leagues operate the Interstellar Alliance's Stock Exchange using a trading database built by Starbase Systems. Unfortunately, the database crashed due to the endeavours of a computer hacker by the name of David Murphy, costing the group millions of credits.
Trust Media is a corporate entity. Possibly a media conglomerate.
United Industries appears to be powerful corporate entity like SynTek and Telic. They also appear to traffic in off-world black market goods, exotic alien flora and fauna, and proscribed xenonarcotics which they purchase in the poorer Allied Systems and then sell in the wealthy Core Systems.