One client, a 60-year-old man who owns a family business with about 500 employees, wants to scale down his company, take a modest salary and move to South America because he feels he is being taxed too much, Adams says. He also fears his employee health care costs are going to go through the roof.

"He feels the current administration has said anyone earning over $250,000 is bad and that they're going to tax them a lot," Adams says. "But that was before November 2. If we now see the Bush tax cuts get extended, that may put a damper on his desire to move."

Adams has another client, a professional baseball player in his early 30s who currently lives in Japan and earns about $1 million a year. The client feels he's being taxed to death in the U.S. Whether that's perception or reality is hard to say, Adams says.

Peter Guang Chen, a CPA and partner at the Chinese law firm DeHeng Chen, says a number of his clients have already given up their U.S. citizenship and moved to Asia, and several more-most of whom earn seven-figure salaries and have at least $20 million in assets-are currently considering it. Several are considering moving to Hong Kong, which has a flat tax rate of 16% and taxes only salary income. Hong Kong also did away with its estate tax in 2006. In the U.S., there was no estate tax in 2010, but it's due to return with a vengeance on January 1, imposing levies of up to 55% on estates valued at more than $1 million (the compromise proposed by President Obama and Republicans in December would lower the rate to 35% on assets of more than $5 million).

"Most of the clients making inquiries already have business or residency in China," Chen says. "It's hard to find someone who will just move there totally out of the blue without having had some connection there."

Relinquishing citizenship is not hard. The person must appear before a U.S. consular or diplomatic official in a foreign country and sign a renunciation oath-though they cannot say they are doing it for tax reasons. Moreover, renunciation does not allow a person to escape pending tax obligations.

The painful part of relinquishing American citizenship is a new exit tax, which basically says if you give up your citizenship it will be deemed to be a sale of all your assets and you must pay the taxes on the capital gains.

Part of the problem for both expats and U.S. citizens with foreign bank accounts is that stringent new banking regulations under the Patriot Act of 2001-intended to prevent money from flowing to terrorist groups-have made it more difficult to keep bank accounts overseas. The law originally had no teeth, but civil penalties were added in the Jobs Creation Act of 2004 and the IRS started to aggressively pursue secret account holders in 2009.

In addition, the Foreign Account Tax Compliance Act (FATCA) was signed into law in March as part of the Hiring Incentives to Restore Employment Act, which, among other things, introduced a 30% withholding tax on certain payments made to foreign entities that fail to comply with specified reporting requirements. The law essentially increased the number of disclosures for U.S. citizens with foreign accounts and assets and increased the penalties for non-compliance.

"The new law made it much more difficult for U.S. citizens and tax residents to hide foreign income," Gluckman says. "These people who had been in nowhere land are all of a sudden saying, 'Now I'm going to have to pay taxes I never paid before. Maybe I'll just give up my U.S. citizenship instead.'"