WRC: How is it funded?

This question comes out of my following the Open Letter to Colin Clark thread which I didn't want to include this post in as it was pretty far off...

Source: http://www.motorsportforums.com/wrc/147693-wrc-how-funded.html

Gary Brabham Jack Brabham† Bill Brack Ernesto Brambilla Vittorio Brambilla Toni Branca Gianfranco Brancatelli