It's entirely contingent upon the conditions of the contract Bungie and Activision have. Generally speaking, Bungie is essentially under the employ of Activision, they all get paid by them to work, however when it comes to the profit share of the IP, the bulk is likely going to Activision to cover their massive 500 million dollar 10 year investment. There's likely many Key Performance Indicators (KPI's) they established in house with Bungie to determine a profit share based on performance which would have a direct correlation to the value of the intellectual property (if the IP does well it's worth more and gets a bit larger share of the profits, and if it doesn't it gets the contractually stipulated portion if any).

You are a sage of wisdom. I sense formal business/contracts/legal education in your past. If not, the you are just one smart dude. I use KPIs every day ;) part of my job.

I've had a class or two =P I tend not to bring it up. That form of honesty tends to come off as boasting, bragging, or just plain haughty.