Facebook's co-founder Eduardo Saverin has renounced his US citizenship ahead of the company going public on Friday.
Brazilian-born Mr Saverin, 30, will avoid paying around $600m (£373m) in tax when he picks up his share of the site's stock offering.
A spokesman said Mr Saverin "found it more practical to become a resident of Singapore since he plans to live there for an indefinite period of time".
He made the move to renounce his citizenship in September 2011.
However, his decision was only made public last week when the US Internal Revenue Service published a list of Americans giving up their citizenship.
Mr Saverin has lived in Singapore since 2009.
He had been sent to Miami in 1993 after his father discovered his name on a list of targets for gangs specialising in kidnapping family members for ransom.
Facebook hopes to raise as much as $10.6bn (£6.6bn) when it makes its initial public offering on Friday, the biggest ever for a technology company.
It is expected to value the company at around $96bn (£60bn).
Mr Saverin holds 4% of the site's stock, the ownership of which is set to put his personal wealth at around $4bn (£2.5bn).
If he were to remain a US citizen, he would be liable for capital gains tax.
Mr Saverin can be credited with much of Facebook's early success.
He was the site's first chief financial officer, putting up the money needed to help Mark Zuckerberg get the social network off the ground.
However, he eventually left the company following mounting disagreements with Mr Zuckerberg - a dispute depicted in the 2010 film The Social Network.