Bungie posted about it. (Destiny)

by Xenos , Shores of Time, Wednesday, April 16, 2014, 00:13 (3873 days ago) @ Schooly D

I don't think Activision is as disconnected as Bungie wanted/wants us to think.

They're putting some massive amounts of cash into the franchise, and despite all the "but we're still completely autonomous" reassurances, you had better believe that Activision is keeping a close eye on where/how their money gets spent.

Bear in mind the "we may be owned by Microsoft but we're completely autonomous" reassurances from the thick of the Halo days which, while partly true, have been shown to be very overblown now that the tape is removed from a lot of mouths.

Right but unless Bungie has the worst legal team ever they should have a contract that keeps it that way.

Here's the theory I'm going with:
1. Marty, something close to a genius and responsible for much of Halo's success, commands a high salary
2. Bungie (optional: and/or ACTV) are getting antsy about this salary
3. Marty finishes Destiny's music (or most of it anyway)
4. Bungie (optional: at the behest of ACTV) meets with Marty to discuss compensation going forward
5. Marty asks for a lot, Bungie (optional: and/or ACTV) won't give it to him
6. Marty decides to leave, knowing there are any number of game studios ready to pick him up and pay him mad cash

I think this jibes with the disparate tones of Bungie's news post and Marty's tweet (including the "without cause" qualifier seems like something resembling bitterness).

It's not a bad theory, but Marty's wording tends to suggest he was fired not that he quit. (Not saying your wrong, just pointing it out). Either he is really bitter they didn't pay him enough or there was some kind of falling out that resulted in Bungie being willing to part with one of the most legendary video game composers of all time.