(CNN) – President Barack Obama's nominee to become U.S. trade representative has almost half a million dollars in an investment account registered in the Cayman Islands, according to disclosure documents submitted to the Senate committee preparing to weigh his confirmation this week.
Michael Froman, currently serving as Obama's deputy national security adviser for international economic affairs, was nominated to the trade post last month.
Republicans have already begun to cry foul, saying Obama's choice of Froman – along with his selection of Treasury Secretary Jack Lew and Commerce Secretary-nominee Penny Pritzker – is hypocritical given his vilification of Mitt Romney's offshore accounts during the 2012 presidential campaign.
Before working for the White House, Froman was an executive at Citigroup and was chief of staff to Treasury Secretary Robert Rubin in the 1990s.
A 2011 document submitted to the Senate Finance Committee showed Froman had a little more than $490,800 held in Citigroup's CVCIGP II U.S. Employee L.P. fund, based at the Ugland House in Grand Cayman.
Ugland House is a building given as the legal address for thousands of investment funds and businesses. The islands themselves are known as a tax haven for U.S. investors and companies.
On Tuesday, Sen. Charles Grassley, a Republican member of the finance panel, wrote in a statement that "President Obama's hypocrisy is piling up with his picks for top posts in his administration."
Grassley noted that in 2009, Obama called Ugland House "the biggest tax scam in the world."
The Iowa lawmaker pointed to two past Obama nominees – Lew and Pritzker – as more examples of what he said was hypocrisy. Lew and Pritzker both faced questions about their offshore accounts during confirmation hearings earlier this year.
The issue of offshore tax havens became an issue in last year's presidential campaign, when Democrats repeatedly slammed GOP nominee Mitt Romney for stashing some of his wealth outside of the United States.
Obama's focus has been on wealthy Americans who store money in so-called tax havens to avoid large bills, not specifically on investment funds that are housed offshore.
Bobby Whithorne, a White House spokesman, said Froman "played no role in creating, managing or operating the fund."
"Mike Froman has paid every penny of his taxes and reported all of the income, gains and losses from the investment on his tax returns. The existence of this investment is not news," Whithorne wrote, adding that Froman had agreed to divest from the fund within 90 days of being confirmed as trade representative.
Froman's nomination garnered support from public figures across the political spectrum ranging from union presidents, to the head of the U.S. Chamber of Commerce, a frequent White House foe.
CNN's Jessica Yellin and Kevin Liptak contributed to this report.