All "US persons", including everybody subject to US taxation. ("the term 'United States person' means (1) a citizen or resident of the United States, (2) a domestic partnership, (3) a domestic corporation, or (4) a domestic estate or trust." http://www.irs.gov/businesses/small/...148849,00.html )

As with the draconian penalties for failure to file forms 5471 (foreign company) and 3520 (foreign trust, Stiftung, Anstalt, etc.) the new law hits hardest those who live abroad, are low-paid and happen to be American citizens. People who couldn't possibly pay the fine.

The last time this sort of vicious anomaly happened -- under the Carter administration when the Sec. 911 foreign earned income exclusion was abolished -- the IRS simply didn't look for cases where (generally because of overvalued exchange rates, as in Nigeria, or excessive cost of living, as in Japan) housing, car and similar allowances would lead to US tax exceeding cash income. (I met a US teacher working in Nigeria whose tax would have exceeded his $25,000 salary.)

It's a shame when Congress, out of hostility (all of this relates to the Forbes series years ago about expatriation to avoid tax as well as a general perception that expatriate Americans are disloyal and that the only reason to have private foreign assets is to cheat on taxes) has created a law that is unenforceable. Such laws lead to disrespect for law in general, and public tolerance of disobedience.

The Philippines was a US protectorate from 1905 to 1946. Its income tax law mirrored the US one following the 16th Amendment and thus Philippines was the only other country taxing its expatriate citizens. By 1999 with repeated devaluations Filipino manual workers abroad fell into the highest tax band. Few could, or did, pay. In that year the Philippines abolished taxation of its overseas citizens. (Prior law: Richard D. Pomp, The Experience of the Philippines in Taxing Its Nonresident Citizens, 17 N.Y.U. J. Int'l L. & Pol. 245 (1985))

Within Switzerland there is an increasing tendency among those with a US connection to use cantonal and private banks with no operations in the USA. This is because the IRS has been known to avoid treaty procedures and to seize assets, or subpoena records, relating to tax investigations for foreign income and assets of US persons by proceeding against the US branch of a foreign bank, or an official of a foreign bank visiting the USA. Here's one interesting case where the bank had to pay twice: to the IRS and then to the Canadian depositor. http://uniset.ca/other/cs6/68OR2d379.html For a subpoena case, see http://www.uniset.ca/other/css/691F2d1384.html