WordNet sense 1 (characterized by the principle of ownership by the state or the people of the means of production):

collectivized

WordNet sense 2 (forming a whole or aggregate):

collective

WordNet sense 3 (subscribing to the socialistic doctrine of ownership by the people collectively):

collectivist, collectivistic, state-controlled

WordNet sense 4 (advocating or following the socialist principles):

socialist, socialistic