Entry and Welfare in General Equilibrium With Heterogeneous Firms and Endogenous Markups
分析了单部门和两部门封闭经济Melitz-Ottaviano模型中市场进入的效率，发现单部门模型下市场进入是有效的，但两部门需求不对称时会导致高需求部门过度进入。
ABSTRACT We analyze market entry efficiency in single‐ and two‐sector closed‐economy Melitz–Ottaviano (MO) models without an outside good. Comparing market and second‐best outcomes, we find that market entry is efficient in the single‐sector model. This efficiency also holds in a symmetric two‐sector setting. When sectors have asymmetric demand and the level of asymmetry is sufficiently small, the market yields excessive entry into the “high‐demand” sector. This inefficiency arises from the presence of an additional aggregator in MO preferences.