Is it meant to be money made only in U2? If not, then Bono does the most outside U2 work, think of all the other albums and songs he's popped up in, the films he's been involved in, extra projects etc. On top of that, it could include investments. You have no idea where Bono has put his money and what it's worth, or any of them for that matter. For example, for all we know, maybe Larry dumped his Achtung Baby money into Yahoo shares back in 1995 and is worth 10x the rest of them.... maybe not, but you get the point. These shows/lists are all pretty hit and miss anyway. They'd only know the truth if they got hold of their tax records, and even then it wouldn't be the whole story.