Eduardo Saverin, the billionaire co- founder of Facebook Inc. (FB), renounced his U.S. citizenship before an initial public offering that values the social network at as much as $96 billion, a move that may reduce his tax bill. Facebook plans to raise as much as $11.8 billion through the IPO, the biggest in history for an Internet company. Saverin’s stake is about 4 percent, according to the website Who Owns Facebook. At the high end of the IPO valuation, that would be worth about $3.84 billion. His holdings aren’t listed in Facebook’s regulatory filings. (full story)