Under new IRS disclosure regulations, details about U.S. bank accounts held by foreign nonresident depositors could be shared with their home governments. As a result, bankers say hundreds of millions of dollars have left Florida since April.

Miami’s position as a hemispheric banking capital could be weakened as some foreign depositors close their accounts in U.S. banks to avoid new disclosure regulations.

The new rules, set to go into effect early next year, require U.S. banks to report interest information on accounts held by nonresident foreign nationals to the Internal Revenue Service, which could then share it with depositors’ home countries. To protect their financial privacy, some international clients have already moved their money to more discreet havens like Panama and the Cayman Islands. “Since April 19 [when the regulation was passed], we’ve heard that several hundred million dollars have left Florida for foreign jurisdictions,” said David Schwartz, executive director of the Florida International Bankers Association. “Customers have said ‘we’re aware of what’s going on, and we prefer to take our money overseas.’”

At play is more than $14 billion in South Florida banks that comes from offshore individuals according to a 2011 survey by the Florida Office of Financial Regulation. That breaks down to 41 percent of total deposits in Florida-chartered banks — generally community banks — plus 90 percent of total deposits in foreign-owned financial entities regulated by the state. Those numbers do not include foreign funds in nationally chartered or federally regulated institutions — a figure that likely would “substantially’’ exceed the $14 billion, according to the survey.

Banking and business groups have opposed the rule, continuing the fight this week by convincing lawmakers to include the tax rule in a Congressional bill that would freeze all “significant regulatory action’’ until the unemployment rate drops to 6 percent. Though the measure passed the House of Representatives Thursday, it is not expected to become law.

The stakes are especially high for South Florida banks because of the concentration of foreign deposits in the region. The Florida OFR survey indicates that 11 of 16 South Florida’s locally based banks could risk failure if faced with a deposit run-off. For 16 of the region’s 22 state-regulated foreign institutions, foreign deposits account for at least 90 percent of holdings. The survey does not name the institutions surveyed.

The impact could go beyond the institutions that are directly involved. Fewer deposits translates into less money to lend; the OFR study shows that a 20 percent decrease in foreign deposits would result in a $25 billion decrease in funds available for community lending.

And if withdrawals were to cause banks to fail, U.S. taxpayers would be stuck with at least part of the tab. The // taxpayer-funded Federal Deposit Insurance Corporation insures $250,000 for each account in a qualifying institutions, regardless of whether the depositor is a resident.

Local business people worry that if the foreign bank accounts go, other types of invetment could go too.

“I don’t see why we would want to make any of these offshore depositors nervous, because they bring tremendous value to us,” said Richard Dailey, president and CEO of Apollo Bank where about 40 percent of accounts are held by foreign nationals. “We use that money to make loans, and they buy real estate and make other investments here.”

Yet some local experts doubt the new disclosure rule will cause a massive outflow of cash from South Florida. Few banking systems are as secure as that of the U.S. Plus, the trend toward increased transparency isn’t limited to U.S. banks. Governments around the world are starting to crack down on tax evasion, which is responsible for up to $280 billion in uncollected income tax globally, according to a report from the Tax Justice Network.

“The effect of this regulation may not be as onerous as some people unfortunately fear,” said Miami-based banking lawyer Bowman Brown. Foreign depositors are “looking at the same thing world wide,” he said, so even those who who want to take their money out of the U.S. may have few alternatives.

Defenders of the new regulation say it’s a necessary gesture so the IRS can access information on accounts held by American nationals in other countries.

“The IRS is not just doing something because they want to penalize banks. They don’t want to waste their time and resources saying that the bankers are the bad guys,” said Ken Thomas, an economist and Miami banking expert. “They must believe that there’s a significant amount of lost revenue to pass something as controversial as this. The banking lobby is very strong.”

Bill Sharp, a tax lawyer with offices in Tampa, San Francisco and Zurich, has been watching what he calls the “mega-trend of global compliance” unfold for more than two decades, beginning in the late 1980s with a trickle of voluntary disclosure campaigns allowing Americans to declare offshore wealth without facing penalties. When authorities started cracking down on funding for terrorism after September 11, 2011, they also uncovered rampant tax evasion that had long gone unchecked.

A major shift came in February of 2009, when the U.S. Department of Justice reached an agreement with the Swiss government that breached the famous secrecy of Swiss banks. The catalyst was a federal case against banking giant UBS that alleged, among other things, that UBS bankers courted wealthy clients at Art Basel Miami Beach, pitching ideas for offshore accounts. UBS entered into a deferred prosecution agreement, agreeing to pay a $780 million penalty and to disclose information on hundreds of U.S. taxpayers who had accounts with the Zurich-based bank.

The IRS saw this case as “the poster child for why we need to attack bank secrecy,” said Sharp, not just for the penalty collected, but also for the thousands of Americans who voluntarily came forward to confess their offshore tax transgressions.

Critics of this recent IRS rule argue that while the new standard of transparency makes sense for countries in Europe and the Caribbean that harbor hidden accounts, few Americans keep their money in Pakistan or Portugal. In total, almost many of the 80 countries are included on the list of countries with which the IRS has promised to share information.

“What American has a banking account in Peru? In Chavez’s Venezuela?” asked Alex Sanchez, president and CEO of the Florida Bankers Association and an outspoken critic of the regulation. “You know what is the No. 1 extortion and kidnapping country in the world? Mexico. What American is going to keep their money there?”

Those dangers are one reason international clients want their finances to remain private. The regulation does include a clause that gives the IRS the option of withholding// financial information in certain situations, but Miami bankers say that this vague promise is not enough to reassure clients. worried about their financial privacy and physical safety.“[Reciprocity] is a great concept if authorities on both sides are reputable, adhere to standards of confidentiality and have a government structure that controls this information,” said Carlos Fernandez-Guzman, president of Miami-based Pacific National Bank, where more than 70 percent of depositors are foreigners. “But that is not necessarily the case in all these countries.

“I have Latin American customers who say ‘don’t send me any bank statements; keep them in the U.S. and I’ll pick them up when I come.’ All of that is for security reasons,” he said. “They don’t want people knowing the extent of their wealth, especially what’s in the U.S., because in their home country it’s a volatile political and criminal environment.”

At the very least, the new rules are causing jitters. His larger depositors, “especially the top 5 to 10 percent,” Fernandez-Guzman said, are “actively beginning to do due diligence.’’

One option for international clients is to put their money into noninterest-bearing accounts that are not subject to the disclosure requirements. Savings accounts are earning little interest at current low rates, and the full amount in checking accounts is insured under the FDIC’s Transaction Account Guarantee program. Though that is set to expire at the end of the year, observers say it could be extended.

The potential loss of foreign deposits comes at the same time that banks face higher capital reserve requirements and a slew of new regulations requiring extensive — and expensive — compliance efforts.

“All of this kind of adds up to the whole regulatory puzzle that we’re all trying to navigate,” said Raul Valdes-Fauli, president and CEO of Professional Bank in Miami. “There’s a lot of uncertainty, and it’s hard to make sure you’re getting your arms around it and implementing the necessary measures. This is a huge burden, especially on smaller banks.”

Still, Miami’s advantages of language and geography— factors that originally helped develop the city’s banking and business culture — will most likely continue to attract foreign depositors, especially from Latin America.

“Miami will continue to be Miami,” said Thomas, the banking expert. “Just at a greater cost.”