The goal of this thesis is to suggest the amendment of the Inheritance and Gift Tax (ISD) as to the accrual date, tax deductions based on kinship, age and disability, tax brackets, and the multiplier applicable to the preexisting wealth of the beneficiary so as to improve compliance with the proportionality principle which is a requirement of tax fairness.

La presente tesis doctoral tiene por objeto proponer una modificación del ISD en la ordenación de su devengo y en las reducciones por parentesco, edad y discapacidad, las tarifas y el coeficiente del patrimonio preexistente, en busca de una mayor adecuación al principio de proporcionalidad que se exige en términos de justicia tributaria.