I thought they owned around 15+ billion worth of it each (if that's not a financial incentive, I don't know what is). Will have to look it up...
edit: Looks like they've been selling some (probably to diversify in other things), but still own a nice chunk: http://www.sec.gov/Archives/edgar/data/1288776/000119312510011019/d8k.htm
And of course, the other part of the 3-headed leader, Eric, owns a bunch too, though not as much.