Do cost efficiency gap and foreign competitors matter concerning optimal privatization policy at the free entry market?

In this paper, we demonstrate that in contrast to the case with exogenous number of foreign private firms, partial privatization is always the best policy for the public firm in long-run equilibrium, which casts doubt on the robust result in Matsumura and Kanda (J Econ 84(1):27–48, 2005) who argued that welfare-maximizing behavior by the public firm is always optimal in mixed markets. Critical cost gap determines that long-run degree of privatization is larger than the short-run one. In particular, regarding the scenario wherein one public firm competes with domestic private firms and foreign private firms, equilibrium price is lower than marginal cost of public firm instead of being equivalent to marginal cost of the public firm, and that public firm’s outputs, profit, and social welfare is the smallest in the concerned mixed oligopoly models.