http://www.answers.com/topic/alwaleed-bin-talal
The thing is, if he decides to dump his stock, Murdoch becomes significantly less rich. The same thing for the billion or so he's invested in Time Warner, ditto Citicorp, Motorola, Apple etc. etc. etc.
How do you figure? If the Saudi Prince dumps his stock, and Murdoch holds on to his, Murdoch still owns the company. In fact, Murdoch himself might very well be the one to snatch up the shares being dumped.