343 Industries is a company made by Wheatley and Bungie rebels because not only did they kill off the Monitor by getting shot by Mr. T's Death Star, but they also paid the former Bungie workers the most petulant thing ever, Cheeseburgers from McDonalds.
This enraged them, so the Monitor, the Bungie rebels, robots and other Forerunner constructs united and created 343 Industries.
How it came to beEdit
Because all the members were Bungie crap, they weren't an independent company yet. Microsoft pissed off Bungie so they ran away from Microsoft. 343 Industries was created in Bungie's place and ran away to Microsoft because Microsoft would've paid them better and not treat them as Cannon Fodder.
Their works in the gaming industry Edit
343 Industries had had many works in the gaming industry, but we can only list the stuff we want because we can.