Halo 4 is by far the most expensive game Microsoft has ever made.
Microsoft Studios boss Phil Spencer told Polygon that Halo is a three billion dollar franchise and the "most important entertainment product in the company".
And asked whether Halo 4, the first series entry not to be developed by creator Bungie, was the most expensive game Microsoft has made, he said: "Absolutely. Nothing's even close."
Microsoft has confirmed a Halo 4 release date of November 6.