From Commonwealth, p7:

Property, which is taken to be intrinsic to human thought and action, serves as the regulative ideal of the constitutional state and the rule of law. This is not really a historical foundation but rather an ethical obligation, a constitutive form of the moral order. The concept of the individual is defined by not being but having; rather than to a “deep” metaphysical and transcendental unity, in other words, it refers to a “superficial” entity endowed with property or possessions, defined increasingly today in “patrimonial” terms as shareholder.