Halo: the Microsoft darling

After launching Halo 3 in late September, which has already made Microsoft $300 million, game developer Bungie is splitting from Microsoft.

An analyst says the departure will avail more avenues to the developer, though Bungie says it remains committed to Microsoft's Xbox 360.

"We're not in a situation where we're running out the door and grabbing Wii and PS3 development kits," Bungie spokesman Brian Jarrard told Reuters.

Microsoft will retain rights to the successful Halo franchise.