Stark has the most. They destroyed Wakanda last I read. And doesn't Reed give something like 99% of his patent money away? Doom is second, if he even uses money, and Xavier and the rest don't even matter.
Out of the second line up, Wayne got it. Was a time when him and Lex are in a panel that Lex was slick pissed about his money being shorter and pondering about why Bruce played stupid when clearly his earnings weren't those of a stupid man.