Fiscal domicile tie breaker: residency determined by permanent home, centre of vital interests, habitual abode, then nationality. Article 4 defines fiscal domicile by treating as a resident any person liable to taxation by reason of domicile, residence, place of management or similar criteria. For individuals dual resident in both Contracting States a hierarchical tie breaker applies: permanent home, centre of vital interests, habitual abode, nationality, and, if unresolved, mutual agreement between competent authorities. For non individuals dual resident in both States residency is determined by the location of the place of effective management.