More on Middlemen: Equilibrium Entry and Efficiency in Intermediated Markets
扩展了Rubinstein和Wolinsky的中间商模型，引入生产和搜索成本，研究均衡进入、效率及动态问题，发现中间商在某些情况下是市场运行的必要条件，且均衡效率取决于议价能力。
This paper generalizes Rubinstein and Wolinsky's (1987) model of middlemen (intermediation) by incorporating production and search costs, plus more general matching and bargaining. This allows us to study many new issues, including entry, efficiency, and dynamics. In the benchmark model, equilibrium exists uniquely and involves production and intermediation for some parameters but not others. Sometimes intermediation is essential: the market operates if and only if middlemen are active. If bargaining powers are set correctly equilibrium is efficient; if not there can be too much or too little economic activity. This is novel, compared to the original Rubinstein–Wolinsky model, where equilibrium is always efficient.