Halo 4 is the most expensive game Microsoft has ever made, Microsoft Studios head Phil Spencer tells Polygon. It is "absolutely" the most money Microsoft has ever spent developing a game, he says. "Nothing's even close."

Estimates for development costs of Halo 3: ODST average out at $60 million, and that was including a massive marketing budget of about $30 million. Halo 3: ODST ended up bringing in more than $170 million in its first 24 hours on the market. Overall, Halo is a $3 billion franchise, Spencer says.