H. Teacher and Researcher Treaty Benefits 1. Most treaties include an exemption from tax income incurred as a result of teaching at an educational institute. Some treaties include researchers as well. All treaties include limitations on the length of the benefit period, typically two years, but not limitations on the benefit amount. Many treaties combine the benefit period limitation under the teacher article with the benefit period limitation under the student article and typically limit the combined benefit period to five years.
Some treaties impose tax retroactively if the individual overstays the treaty period.
Newer treaties allow the treaty benefit one time only. Some older treaties allow multiple benefits if the individual reestablishes his or her tax residency and physical presence in the treaty country for a substantial period, typically one year, before claiming benefits again. The character of the entity for which teaching or research is performed. Whether or not the individual qualified for treaty benefits previously. In the case of researchers, whether or not the research is for public or private benefit.