Statement from Bungie's official website.
We have enjoyed a successful eight-year run and would like to thank Activision for their partnership on Destiny. Looking ahead, we’re excited to announce plans for Activision to transfer publishing rights for Destiny to Bungie. With our remarkable Destiny community, we are ready to publish on our own, while Activision will increase their focus on owned IP projects.
Looks like Bungie just got sick of Activision's bullshit demands. This coming hot on the heels of Activision Blizzard losing 2 CFOs in quick succession, and Mike Morhaime leaving Blizzard altogether in April, it looks like Bungie are picking the perfect time to abandon ship.
Couple of juicy tidbits here:
1. This has been in the works for years, apparently due to tensions in their relationship.
2. When this was announced, Bungie devs cheered loudly.
If this is true, it definitely sounds like it was Bungie who jumped and not Activision who pushed.
Good on them. F*** Activision Blizzard.