This paper develops a dynamic general equilibrium model with heterogeneous firms that face search complementarities in the formation of vendor contracts. Search complementarities amplify small differences in productivity among firms. Market concentration fosters monopsony power in the labor market, magnifying profits and further enhancing high-productivity firms’ output share. Firms want to get bigger and hire more workers, in stark contrast with the classic monopsony model, where a firm aims to reduce the amount of labor it hires. The combination of search complementarities and monopsony power induces a strong “Matthew effect” that endogenously generates superstar firms out of uniform idiosyncratic productivity distributions. Reductions in search costs increase market concentration, lower the labor income share, and increase wage inequality.

本文开发了一个动态一般均衡模型，其中异构公司在供应商合同的形成过程中面临搜索互补性。搜索互补性放大了公司之间生产力的微小差异。市场集中促进劳动力市场的垄断力量，扩大利润并进一步提高高生产率企业的产出份额。公司希望扩大规模并雇用更多工人，这与经典的垄断模式形成鲜明对比，后者的目标是减少雇用的劳动力数量。搜索互补性和垄断力量的结合产生了强烈的“马太效应”，这种效应从统一的特殊生产力分布中内生地产生了超级明星公司。搜索成本的降低提高了市场集中度，降低了劳动收入份额，并加剧了工资不平等。