Tax residency rules determine treaty residency using permanent home and centre of vital interests, with habitual abode and nationality tests. Defines resident as any person liable to tax in a Contracting State by domicile, residence, place of management or similar criteria, including the State and its subdivisions but excluding persons taxable only on source income. Dual resident individuals are subject to sequential tie breaker tests: permanent home, centre of vital interests, habitual abode, nationality, and finally mutual agreement. Dual resident non individuals are deemed resident where their place of effective management is situated, with unresolved cases to be settled by mutual agreement of the competent authorities.