Updated May 15, 2012: Eduardo Saverin, the Brazilian-born co-founder of Facebook with a 4 percent stake in the company (worth about $4 billion) reportedly renounced his U.S. citizenship last year to avoid or at least minimize the tax bill from future sales of stock in the company, and other investments. Unlike most countries, the United States imposes income tax on citizens as well as residents, and the capital gains tax on existing investments cannot be avoided entirely just by dropping citizenship, but it can sometimes be reduced. By renouncing his citizenship, Saverin will be taxed on the much smaller estimated gains that likely would have occurred if he had sold his stock last year, well before the initial public offering. For a detailed discussion of the so-called expatriation regime (exit tax), go to CEB’s California Estate Planning §§16.85–16.90A.
Facebook has announced that Mark Zuckerberg will exercise 120 million options to purchase the company’s stock in connection with its planned initial public offering, potentially resulting in a $2 billion tax bill.