My understanding from discussions with an intellectual property lawyer is that everybody who works on creating a recording owns it jointly and nobody can exploit it without everybody else's permission. His impression was that whoever put up the money didn't automatically own the master unless a contract assigned ownership to them.
Incidently, the idea that record labels own the masters of all of their artists' recordings is internet mythology. An amazing percentage of artists actually own their masters and lease distribution rights to a label.
I created an FAQ about a bunch of this stuff:
http://thewombforums.com/showthread.php?t=183