The literature on both entry deterrence and the influence of special interest groups is extensive. In this paper we attempt to marry these strands of literature by developing a model of entry deterrence through interest group influence in an entry re-regulation context. In contrast to other entry deterrence models, we are able to investigate how product market rivalry affects the regulator's equilibrium entry decision, firms' output decisions, entry deterring activities and equilibrium welfare. We find that in equilibrium more collusive industries tend to lobby more but that the regulator attempts to compensate for weak price rivalry by allowing greater entry. The latter effect tends to offset the former, possibly entirely so that the overall welfare effect is ambiguous.
entry regulation entry deterrence incumbent lobby group Quasi-Cournot conjectural variation.