You know what’s cooler than a billion dollars? Renouncing your U.S. citizenship not long before the company you co-founded has as IPO, as our pal Eduardo Saverin did. This may be tax-related — Saverin stands to get a bigger chunk of the Facebook IPO pie now that he’s no longer a U.S. citizen, though the Singapore resident won’t avoid taxes entirely — as capital gains for renounced U.S. citizens face exit taxes.