According to a 2011 financial document, Mr. Froman held $490,845 in a fund managed by Citigroup and based in Grand Cayman’s Ugland House, a modest whitewashed building that has been widely cited as a symbol of tax avoidance since it is home to nearly 19,000 business entities seeking favorable tax treatment.

In answers to Finance Committee questions, Mr. Froman said on May 17 that he still held those assets but would sell them off within 90 days of confirmation as trade representative.

Mr. Grassley said the president once called the Ugland House “the biggest tax scam in the world.”

“Yet he nominated two top advisers in a row who invested in the Ugland House,” Mr. Grassley said. “He also nominated a commerce secretary with significant offshore income.”

Mr. Froman’s 2009 financial disclosure forms showed holdings in three different Citigroup accounts that maximize profits through “carried interest,” a tax loophole that allows private equity and hedge fund managers to claim compensation as capital gains, thus paying a lower tax rate than if that pay is taxed as income.

Mr. Froman received a $2 million payout from Citigroup to waive his holdings in the India Infrastructure Carried Interest Plan and from another investment called the Sustainable Investments Carry LP. Another account, Citi Infrastructure Investors Carried LP, showed $1 million to $5 million in assets in 2009. Those assets were transferred to his wife, Nancy Goodman, who has promised to divest them as soon as he is confirmed. But White House officials say their value in his latest financial disclosure was revised to zero because of fund performance.

As the financial industry went into a tailspin, Mr. Froman received a bonus in 2008 of $2.75 million, based on his performance the year before. In 2009, his bonus for 2008 work was $2.25 million. The justification for these bonuses given to the committee was “normal industry practice.”