This excerpt taken from the ATVI 10-Q filed Feb 8, 2006.
Ownership and Goodwill. Publisher acknowledges Microsofts ownership of all Licensed Trademarks and all goodwill associated with the Licensed Trademarks. Use of the Licensed Trademarks shall not create any right, title or interest therein in Publishers favor. Publishers use of the Licensed Trademarks shall inure solely to the benefit of Microsoft.