Tom Goodman, a spokesman for the former Harvard student who was an early investor in Facebook, said it was "not for tax reason," that Saverin, who was born in Brazil, is renouncing his U.S. citizenship.
"Eduardo recently found it to be more practical to become a resident of Singapore since he plans to live there for an indefinite period of time. He still has very strong ties to Brazil and is extremely passionate about not only his homeland, but also the United States," Goodman said in an e-mail.
CNNMoney reported Saturday that renouncing U.S. citizenship is very rare, but becoming more common.
Only 1,781 people did so in 2011. By comparison, less than 450 did so in 2008.
It is unclear how much of Facebook Saverin still owns, but he was not listed in a regulatory filing as owning more than 5 percent of the company.
How much his share is worth will be decided soon. Facebook is expecting to raise $1.1 billion in its initial public share offering, which is expected to occur Friday with shares priced between $28 and $35 per share.
Facebook said the average tax bill for its employees after the IPO will be $1.1 million.