Imagine being excluded from the financial services industry because of your passport.

That happened to Carrie Walczak, an American living in Germany, in May. She received a letter from Deutsche Bank informing her that her bank account was going to be closed because she is an American.

Walczak, a 37-year-old from upstate New York, lived in Brussels for seven years with her Belgian husband before moving to Bad Homburg, Germany, where she has resided for the past 18 months. Walczak says the letter informed her of new tax regulations required by the U.S. government, and because of that she is being dropped as a customer.

She says that a second bank account, from a financial institution based in Brussels, remains open -- but only because she signed two documents allowing the bank to disclose all of her banking information to the IRS. She has a third bank, based in Germany, which hasn't sent any letters to her.

"So that seems safe for now," Walczak says, admitting that she is rattled. "The problem is that to get paid and to have a normal life, one does need a bank account. If eventually other or all banks follow Deutsche Bank's lead, it could make my life very difficult."

Not to mention for all American expats, who number between 5 million and 6 million. In 2010, the Foreign Account Tax Compliance Act (FATCA) became law in the United States, making it harder for American taxpayers to hide assets.

Foreign banks and other financial institutions are required to give information to the Internal Revenue Service about Americans' accounts worth more than $50,000. There is a slight reprieve - in 2014 and 2015 the law is in a "transitional period," with the IRS not taking punitive measures if a bank appears to be making a good-faith effort to comply.

Many of the account-closing complaints are coming from Americans living in Switzerland, according to David McKeegan, co-founder of Greenback Expat Tax Services, headquartered in Hong Kong.

That is due to Switzerland's banking troubles in recent years. In 2009, UBS paid a $780 million fine to the IRS for helping American taxpayers hide money abroad. In May, Credit Suisse was fined $1.2 billion for similar charges.

Neither firm made executives available for comment.