The Collaborative International Dictionary of English v.0.48:

collectivized \col*lec"tiv*ized\ a.
   brought under collective ownership and operating under
   collectivist principles; -- used especially of organizations
   operating under the ownership by the state.

   Note: [Narrower terms: socialistic (vs. capitalistic),
         socialist; communistic]

   Syn: collective, collectivised, state-controlled.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

collectivized
    adj 1: characterized by the principle of ownership by the state
           or the people of the means of production [syn:
           collectivized, collectivised]
    2: subscribing to the socialistic doctrine of ownership by the
       people collectively [syn: collectivist, collectivistic,
       collectivized, collectivised, state-controlled]