Free entry and social inefficiency under co-opetition

We investigate the social desirability of free entry under co-opetition where firms compete in a homogeneous product market while sharing common property resources that affect industry-wide demand. Our findings indicate that free entry leads to socially excessive or insufficient market entry, depending on the commitment of investment in common property resources. In the non-commitment case, where quantities and investment are simultaneously chosen, there is a possibility of insufficient entry. However, in the pre-commitment case, where investment is chosen at a prior stage, free entry leads to excess entry and a reduction in common property resources. Interestingly, in this case, the excess entry results of Mankiw and Whinston (RAND J Econ 17:48-58, 1986) hold even without entry costs or economies of scale. These results have important policy implications for entry regulation.