The company's name could be a reference to Traxus IV, an AI that went rampant in the Marathon series.
In Halo 3, Traxus has been seen on the cargo crates, similar to the way COBB Industries was referenced on crates in Halo 2. Based on these appearances, it is probably some form of shipping or transport company, or perhaps manufacturing.
Bungie insider backstory: Traxus is SUXART spelled backwards. After repeated denied attempts to get 'Askloun' into the game, Traxus was the second attempt to sneak something sophmoric into the canon. Askloun did make it into a multiplayer map, but you'll never find it, even though it's in the open.