Ultor
The Ultor Corporation is the mining company mainly operating on Mars you rebel against in Red Faction and the name of the company which is formed in Red Faction II. It is unknown whether Ultor plays a part in Red Faction: Guerrilla or not. The Ultor symbol has been spotted on propaganda in Red Faction: Guerrilla, and the Nano Rifle features an Ultor symbol; however this is most likely because the nano-forge powering the gun was created by ..., an enemy in Red Faction and an employee of Ultor.
Ultor began as a small-time clothing company, but worked its way up to being an enormous mega-corp, that eventually turned its attention towards Mars. In Volition's Saints Row 2, Ultor owns the city of Stilwater.