Almost 50 years after Oscar-winning actor Yul Brynner gave up his passport at the U.S. embassy in the Swiss capital, the number of Americans relinquishing their citizenship jumped 47 percent in the first quarter.

Expatriates giving up their nationality climbed to 1,001 in the three months through March from 679 a year earlier, according to Federal Register figures released May 2. The number tripled to 3,000 in 2013 from the previous year, Internal Revenue Service data shows.

While Brynner, the star of “The Magnificent Seven,” renounced his American citizenship in Bern following a dispute with the IRS, tougher asset-disclosure rules being introduced in July are prompting more of the estimated 6 million Americans living overseas to weigh giving up their passports. The appeal of U.S. citizenship for expatriates dimmed further as 106 Swiss banks prepare to turn over account data on American clients to avoid prosecution for helping tax evaders.

“I feel caught in the battle between the government and the banks,” said John Annen, a 46-year-old American mathematician who has lived for more than decade in Switzerland. “The U.S. government is the biggest threat to my style of living.”

The U.S., the only nation in the Organization for Economic Cooperation and Development that taxes citizens wherever they reside, stepped up the search for tax dodgers after UBS AG, Switzerland’s biggest bank, paid a $780 million penalty in 2009 and handed over data on about 4,700 accounts.

Tax Problem

While Zurich-based Annen said his American citizenship makes him an “unwanted customer” of Swiss banks, he hasn’t considered relinquishing his passport.

That makes him an exception. More than two-thirds of 400 U.S. expatriates surveyed in November by Zurich-based deVere Group said they had considered giving up their passports.

Banks in Switzerland, the largest cross-border financial center with $2.2 trillion of assets, have discovered that thousands of their clients have dual U.S.-Swiss citizenship, obliging them to make voluntary disclosures, said Matthew Ledvina, a U.S. tax lawyer at Anaford AG in Zurich.

“Those banks have been checking through accounts and informing clients they have a big tax problem,” said Ledvina. “The number of people renouncing their citizenship will probably rise as the banks enforce U.S. tax rules.”

Risk Evaluation

The U.S. has allowed some Swiss banks seeking to avoid prosecution for handling undeclared American money a two-month extension until the end of June to deliver account data.

Some institutions reject certain American clients “for reasons of risk or cost evaluation,” said Sindy Schmiegel, spokeswoman of the Basel-based Swiss Bankers Association, which represents more than 300 banks.

Both UBS and Credit Suisse Group AG, the biggest Swiss banks, said they offer Americans checking and savings accounts. UBS also will grant mortgages, though not accounts for securities transactions.

While it’s fair for the U.S. to pursue tax evaders, the Foreign Account Tax Compliance Act, which will compel foreign banks to share the account details of American clients, is “causing a lot problems,” said Marylouise Serrato, executive director of Geneva and Washington-based American Citizens Abroad, which campaigns for taxation based on residency. The more than 20,000 Americans living in Switzerland have faced particular challenges, given the country’s tradition of bank secrecy, she said.

Fatca Misunderstanding

The July 1 implementation of Fatca “is a reflection of the misunderstanding in Washington what it means to be an average American living and working overseas,” she said.

Fatca requires U.S. financial institutions to impose a 30 percent withholding tax on payments made to foreign banks that don’t agree to identify and provide information on U.S. account holders.

When Zurich’s Iowa-born mayor, Corine Mauch, gave up her U.S. passport last year, she said that while the move wasn’t motivated by U.S tax rules, she wouldn’t “miss the U.S. tax bureaucracy either.”

The U.S. Embassy in Bern declined to comment for this story.

Brynner, who won an Academy Award for his role in “The King and I,” renounced his American citizenship in 1965, saying he wanted to be closer to his family who lived in Switzerland, according to the 1989 biography -- “Yul: The Man Who Would be King” -- by his son, Rock Brynner.

Not Welcomed

“It’s really simple to run afoul of the law,” said Martin Naville, chief executive officer of the Swiss-American Chamber of Commerce in Zurich. While most banks have some kind of offer for Americans, “you’re not really welcomed with opened arms,” he said.

The additional compliance costs for companies to ensure that Americans they hire are filing the correct U.S. tax returns and asset-declaration forms are $7,000 per person, according to Ledvina. For individuals, U.S. accounting costs are about $4,000 per year.

“For every person who has actually given up their citizenship there are 100 Americans abroad who are throwing up their hands at their tax situation,” said David Kuenzi, founder of Madison, Wisconsin-based Thun Financial Advisors. “Its not about people not wanting to pay their taxes -- it’s about the infuriating difficulty of paying your taxes.”