A record number of Americans are giving up their U.S. citizenship. The Wall Street Journal reports that 1,130 Americans renounced their citizenship in the second quarter of 2013, more than did so in all of 2012.

To my surprise, the list of new ex-Americans is publicly available; I didn't recognize any of the names on a quick scan.

According to the Journal, the surge in expatriations seems to be driven by the upcoming implementation of the Foreign Account Tax Compliance Act (FATCA), a 2010 law that forces foreign financial institutions to disclose more information to the IRS about Americans' accounts and investments. Starting in 2014, foreign financial institutions will have to tell the IRS about income accruing to American clients (or businesses owned by Americans), and they'll have to withhold American income tax as appropriate.

In other words, it's going to become a lot harder to hide your income with a Swiss bank account.

The IRS can't directly tell foreign banks what data to turn over. But it has a pretty big stick — it can impose a 30% withholding tax on payments from the U.S. to foreign financial institutions unless they cooperate. As a result, many foreign banks and foreign countries have been entering into agreements with the IRS to comply with FATCA.

If you're an American living in the U.S. and your strategy for hiding income abroad isn't working anymore, you may have few options but to pay up. But if you live abroad, you have another choice available: Renounce your U.S. citizenship so you're not liable for American income tax.

That's one driver of the surge in renunciations. Another likely factor is the increase in capital gains and income tax rates in 2013, meaning that wealthy American expatriates can get a bigger tax saving by renouncing citizenship than they used to.

But a third factor is that FATCA creates compliance headaches apart from the actual tax bills it leads to. As the WSJ describes:

Some U.S. citizens say they are exasperated by a growing raft of paperwork that forces U.S. citizens living abroad to declare the minutiae of their financial holdings and other assets. That has increased the attraction of becoming a citizen in places such as Hong Kong, where the individual tax rate is capped at 15%.

"My decision was less about the actual amount of taxes I had to pay, and more about the system," said one investment banker, who renounced his U.S. citizenship and is now a Hong Kong citizen. "I'm not an ultrawealthy dude. It was the hassle with all the paperwork."

A few months ago, I attended a dinner where I sat between two Americans living abroad who complained that FATCA has made foreign banks less willing to provide American expatriates with checking accounts, credit cards and mortgages. This has been a major point of complaint for organizations representing American expatriates.

FATCA also complicates matters for foreign businesses with American investors (and for Americans who want to invest in foreign businesses) since American ownership makes a business subject to FATCA reporting.

If you intend to move back to the U.S., you're probably not going to renounce your citizenship because it was hard to get a checking account, or even because you had to forego an investment opportunity. But if you're a dual citizen with weak ties to the U.S. and the law is materially interfering with your financial dealings, it might be a reason to go ahead and quit being an American.

Marie Sapirie, the legal editor at Tax Notes, even says the IRS proposed renouncing citizenship as an option for an American with a complicated tax situation who had long resided abroad.

Last fall, I attended an American Swiss Foundation trip to Switzerland and FATCA was the number one hobby horse for the Swiss participants. The difficulty in evaluating the Swiss complaints is that the Swiss have a combination of good and bad reasons for hating FATCA. The law creates compliance burdens for Americans living in Switzerland and Swiss who do legitimate business with Americans. But it also undermines tax evasion strategies that are the key reason that some Americans were interested in banking in Switzerland in the first place.

Of course, every law has compliance costs, and it's not even clear that it's such a big problem if more Americans, presumably dual citizens living abroad with relatively weak ties to the U.S., are renouncing citizenship. But the benefits of FATCA may also be relatively modest: It's expected to raise $7.6 billion in added taxes over 10 years.

In 1999, the State Department estimated that there are between three and six million Americans living abroad; if those numbers are similar today, that means FATCA will generate about $170 in extra annual taxes per expatriate.

The revenue estimate for FATCA may prove incorrect in either direction; it's based on a guess about how much unreported foreign income will be discovered when the new reporting and withholding requirements come into effect. As the law is implemented next year, we'll start to see how much revenue actually rolls in — and whether the law is worth the compliance costs and expatriations that it causes.