Here are some of the other categories of foreign workers subject to special taxation rules:
Athletes & Entertainers
Foreign athletes and entertainers generally must pay US income tax on their US source income. This includes compensation for performances, endorsements, the sale of merchandise, and royalty, or other, income closely related to the event. These taxpayers are generally subject to special withholding rules. They are required to file a U.S. federal income tax return to report and pay any US tax. See Taxation of Foreign Athletes and Entertainers for more details.
Foreign agricultural workers temporarily admitted into the United States on H-2A visas are exempt from U.S. Social Security and Medicare taxes on compensation paid to them for services performed in connection with the H-2A visa. This is true whether they are resident aliens or nonresident aliens. In addition, compensation paid to H-2A agricultural workers for services performed in connection with the H-2A visa is not considered to be "wages" for purposes of federal income tax withholding, and thus is not subject to mandatory withholding of U.S. federal income tax unless Backup Withholding applies. See Foreign Agricultural Workers for more details.
Governments and Organizations
U.S. investment income earned by a foreign government is not included in the gross income of the foreign government and is not subject to U.S. withholding tax. U.S. investment income means income from investments in the United States in stocks, bonds, or other domestic securities, financial instruments held in the execution of governmental financial or monetary policy, and interest on money deposited by a foreign government in banks in the United States. See Foreign Governments and Certain Other Foreign Organizations for more details.
International organizations are exempt from U.S. tax on all U.S. source income. This income is not subject to NRA withholding. International organizations are not required to provide a Form W-8 or documentary evidence to receive the exemption if the name of the payee is one that is designated as an international organization by executive order.
"Au pair" is a French phrase meaning "the par" or "the peer" [level], and is used to describe someone who boards temporarily in someone else's home. In the United States the term has come to have a narrow, technical meaning which describes a class of Exchange Visitors who come to the United States under the auspices of a program administered initially by the United States Information Agency (USIA), and more recently by the Bureau of Educational and Cultural Affairs (ECA) of the Department of State. At any one time, there are approximately 12,000 au pairs in the United States. An au pair is always admitted into the United States on a J-1 visa, and is not allowed to remain in the United States longer than one year. An au pair must be between the ages of 18 and 26. They are usually students who participate in the program in the United States for the educational and cultural experiences it provides them.
Most au pairs are nonresident aliens, and therefore will be required to file Form 1040NR or Form 1040NR-EZ to report their au pair wages. As a nonresident alien, an au pair is not eligible for the Earned Income Tax Credit, the American Opportunity Credit and the Lifetime Learning Credit. An au pair is not really a "student" in the United States, and therefore is not eligible to exclude his/her au pair wages from gross income under the student article of any U.S. income tax treaty. An Au Pair who is a nonresident alien is not required to file a U.S. federal individual income tax return if his only U.S. source income is wages in an amount less than the personal exemption amount. See Au Pairs for more details.
Dual Status Aliens
You are a dual status alien when you have been both a resident alien and a nonresident alien in the same tax year. Dual status does not refer to your citizenship, only to your resident status for tax purposes in the United States. In determining your U.S. income tax liability for a dual-status tax year, different rules apply for the part of the year you are a resident of the United States and the part of the year you are a nonresident. The most common dual-status tax years are the years of arrival and departure. See Taxation of Dual Status Aliens for more details.
The expatriation tax provisions under Internal Revenue Code (IRC) sections 877 and 877A apply to US citizens who have renounced their citizenship and long-term residents (as defined in IRC 877(e)) who have ended their US resident status for federal tax purposes. Different rules apply according to the date upon which you expatriated. See Expatriation Tax for more details.