Suppose an individual who is a resident of the United States has resided and worked within the country from January 1st until May 15th. On the morning of May 15th, they travel to Canada and, in the afternoon, promptly begin a new chapter of their life.
In Canada, for the sake of argument, they immediately secure employment with a new Canadian company and cease to have any income or expenses associated with the United States. Furthermore, let's assume that this individual is not a U.S. citizen. As a result, they are not subject to ongoing U.S. taxation regardless of their geographical tax residency status.
How would the taxation periods be delineated then? Specifically of interest is the overlapping day of May 15th.
Jan 1 - May 15 (US tax resident) + double taxed on May 15th
May 15 - Dec 31 (Canadian tax resident) + double taxed on May 15th
Jan 1 - May 15 (US tax resident)
May 16 - Dec 31 (Canadian tax resident)
Jan 1 - May 14 (US tax resident)
May 15 - Dec 31 (Canadian tax resident)