question re. kernel licenses

Perhaps a silly question, but who actually holds the copyright on the kernel? I know it's released under the GPL, but, for the life of me, I can't find any statement of who is actually granting the licenses (i.e., who holds the copyright), and I can't seem to find any kind of copyright assignment statement that contributors are required to execute. So, how does this all work? Thanks! Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra