As per the invest-faq.com, a non-resident alien is able to enjoy holding some investments in this nation (USA) while at the same time getting numerous tax exempts upon income gained from the investments. A good example is the situation where a citizen of the US does his job in the USA for a considerable time period and gets a good portfolio of securities while in the USA. This person can hold on to that portfolio perfectly regardless of whether she/he stays in the USA afterwards.
The term or expression non-resident alien also encompasses such nationals from foreign countries who happen to reside in the USA such as students. These non-resident aliens who have US holdings are obliged to comply with the rules of the USA taxation system as the taxation authority of the US enforces such, the IRS. Since the taxation laws of the USA seem complicated, non-resident aliens need to consult tax advisors who have all taxation issues on their finger tips.
Fundamentally, a non-resident in USA, for taxation purposes, has to spend a period of lesser than 183 days in the USA. The rule governing this is complex in a way since it considers the previous years as well, as per the publication number 519 of the IRS. (Invest-faq.com, 2009)
Several court cases for non-resident alien taxation cases have been heard and resolved in court. Examples include Storerios and Catherine Hantzis versus CIR and Michel versus Commissioner among others.
In the case of Storerios and Catherine Hantzis versus CIR, the initial circuit of the court of appeal for the USA stated that a full-time student of law who is unemployed and is residing in Boston and at the same time attending classes in the Harvard Law School which is in Cambridge, who decided to take up a job for summer in the New York for 10 weeks got a tax home in New York alone since New York was her employment location. Thus, being an employed full-time student kind of status in his residence, Boston was not enough to take that as her