An introduction to “tax residency” …
Most people equate residency with physical presence. They assume that where you are physically presence determines where you live. They further assume that where you live is where you pay your taxes. Conclusion: The country where you live is the country where you must be “tax resident”. Not necessarily!
There is no necessary correlation between where one lives and where one is a “tax resident”. In fact, “residency for tax purposes” may be only minimally related to “residency for immigration (where you live) purposes”. It is possible for people to live in only one country and be a tax resident of multiple countries. The most obvious example is “U.S. citizens residing outside the United States”.
— John Richardson – lawyer for "U.S. persons" abroad (@ExpatriationLaw) December 15, 2016
The concept of “tax residency” is fundamental to all systems of taxation. The fundamental question, at the root of all tax systems is:
“what kind of connection to a country is required to assume tax jurisdiction over an “individual”, over “property” or over an “entity”?”